I like the concept of this video allan, also helps the client to understand what we reccommend is for best results not always guaranteed workmanship but by doing it here, i believe he would avoid a cowboy coming in and making a disaster of it 👍
Great advice! Thanks! I am considering replacing a 30+ year old Potterton Kingfisher RS 50 CAT 1N boiler. The hot water tank iis gravity fed with an overhead tank. Thermostatically controlled power shower require such a tank. OJ Gas & Heating (a WB Accredited installer!) said that he will fit a combi, remove the hot water tank and replace the shower with another type. After watching videos and reading the forums, I am planning to fit a Greenstar 12/15Ri boiler. I can not fathom why a WB Accredited installer recommended fitting a combi
I’m a qualified gas engineer enjoy your videos keep up good work, I would personally would install a combination boiler for me I prefer ideal logic or I would install a Worcester as they are good boilers if install correctly all depends on how much they want to spend!!
Combis are so convenient.....and easy to install....but to me a Rolls Royce system is a system boiler with an unvented cylinder as long as you have space for the cylinder. No header tank is needed, but the biggest benefit is that if it breaks down you still have hot water via the Immersion, and you use a fan heater for temporary heat. If a combi breaks down its a crisis, if a system boiler breaks down its an inconvenience. I had two Elans, one installed in 1983 and the other (new house) in 1985. I have a heat only Logic on Y plan in current house. It was an Ideal turbo 2 condenser previously and that gave very little trouble over 25 years. As to make of boiler...just choose a reputable make with a decent guarantee. I think you are aware of the current best buys.
As a company and incredited installers, we always fitted Worcester's , but many years back I fitted an Ideal for a customer and was really impressed. Long gone are the regular burnt out pcb,'s of old. I fitted a logic + in my house five years ago and can't fault it. Much better price than a Worcester too
Hi Allen i am a GSI on the East coast i think in this situation i would be advising another modern open vent boiler , and replace the old cylinder afterall it is as old as the boiler ? the pipework can then be tidied up in the airing cupboard , the radiator valves would need changing and throughly clean the system and fit a magnetic filter , clean out the storage tanks and replace the ball valves, and upgrade all the contols to a Honeywell s plan system . I would not want to pressurise the old pipework and exsisting system changing like for like is the safer option . Regards Wayne
Hi Wayne, thanks for your input. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I agree there is a real risk of introducing higher pressure to the existing pipework.
Wow, back to the 70s! Do you provide the flared pants as well? :) An intergas can be run open vented with an F&E tank. They advise to keep the internal pressure vessel connected, even though open vented. Keeps local pressure away from heat exchanger A few years back fitted an Intergas to a 40 years old open vent system. Kept the F&E tank to avoid the rads popping. Working brilliantly since. See my post.
Both my hot and cold supply into the bathroom are tank fed ,it's a bungalow and there is no problem with the cold pressure,I am just wondering if there is a problem with say the gate valve not fully open or sheared so you are moving the wheel head but the gate is not opening ,I have had this a couple of times with old gate valves obvious if it's snaped when you have closed the valve for some reason not so if it is half way open.The chap is obviously quiet handy so moving to a condensing boiler would knock that one on the head. There might well be an issue with spare parts for the old boiler although a lot of stuff is still available as it was common to many boilers . If you must I would change like for like ,He can continue to maintain everything but the boiler.but consider you are swapping these new boilers every 10 years he would be on his fourth condensing boiler now ,and they make out this is progress!
Hi John thanks for your input. The cold feed to the bathroom works fine with good pressure, I just want drinking water at the sink tap rather than tank fed water. The old boiler has been great, but is really noisy some days on startup (sounds like a Jumbo coming in to land). I was advised it was the heat-exchanger, but these have been obsolete for 8 years plus, so I running on borrowed time really, and its also a bit of a gas guzzler by modern standards. So I'm looking to upgrade over the summer.
Hot water tanks are only inefficient if old and you keep the hot water on 24 hours. I am an energy surveyor and modern tanks are fine if you only heat once a day. It can easily do three 10 minute showers. Heat for 2 hours a day, enough to get to shut of temp of 60 Celsius and just have that repeat daily. If you need more showers, top up once for an hour. It just needs some planning. Keeping a water tank on 24 hours costs twice that as once a day, purely because of heat loss from the tank. Having said that, with more insulation, the issue of timing the water to come on is less of an issue and doesn't affect your gas usage. I've also seen some bare copper cylinders in my time and the cupboard it is in is a sauner.
This is a great video Allan well done. I would go for Ideal combi 35kw. Obviously I would powerflush the system first, then I would definitely upgrade the gas pipe that’s very very important running the right size from the meter all the way to the boiler taking in consideration other gas appliances in the house, pressure loss less than 1mbar. With the clean system I would install a 22mm fernox filter, acidic neutraliser and descaler on the mains. By installing the combi you would get rid of both tanks gaining some space. Like Allan said there might be a need for changing the shower because of the mains pressure.
Hi Alan, I'm also an Electrician, I installed an open vent system powered by a Potterton Netaheat Mk IIF in my house back in 1984 which is still going strong - no problems. Of course the boiler will eventually have to be replaced which will put me in the same situation as Dave here. But I will be staying with an open vent system. Why not? reliable! cheaper! no messing around the place altering pipework etc! I don't like Combi boilers, I've heard too many complaints about them from customers whilst I was working for a central heating company, although that was quite a while ago and they no doubt have got better. Anyway I thought I would throw that in here as a different outlook to all the Combi fanboys here. Love your videos!
It’s all about how it’s installed, I have never heard a complaint about a boiler that’s been specified correctly, I wouldn’t have an open vent in my own house but sometimes there are no choice.
Viessmann 111 W Storage Combi or Saunier Duval Combi ( Vaillant) I think and I think the old copper and all can deserve to remove and replace to bew MLCP manifold system... I know is very pricey job but worth on long run... Nice video Allan
Hmm As a non Plummer I would want to check out the pipe work in the bathroom first to see just what was put in , and do a flow test , if it was more than 15 on the water and then do a gas feed check. the tank being old should be replaced given the cost of doing both , given the limited water usage , with just 1 bathroom I would say go high end combi or an in between such as a vittadenns 111f that should cope with the property for when the kids visit. If there are plans to add a second bathroom/on suite I would say go system and free up the loft
Hi Alan Assuming there is good water flow, customer is ok spending a little bit more I would go with a 30kw to 35kw ideal logic max combi. It should fit inside the cupboard unless thee is a better place for it. It gives enough hot water flow and you can sort out the bathroom at the same time killing 2 bird and all that. Phill.
I'd loved to have had my new English oil boiler fitted, but the guy ran off with thousands of our pounds, left us with a new boiler that won't work with the French domestic heating oil, so no one will touch it. So in answer to your question, what system to have. I'd say, just one that works would be great. BTW, I love your videos. Invalid living in France.
I've got a copper cylinder with a potterton condensing Gold H15,whilst my plumber was here exchanging 2 automatic air vents he told me that my pump is now discontinued because of EU regulations so if it goes wrong I'm screwed is that correct because my system is gravity fed fully pumped system,do you think there is a pump I can purchase allowing me to continue with my present boiler which has just reached its tenth year,I googled the manufacturers and they said that boiler should run efficiently for a minimum of 15 years,my plumber did it's tenth year check on it 2 weeks ago and he said his readings were good
I'm going to update my open vent system this summer, it's ancient but going strong. The biggest dilemma for me is hot water cylinder with system boiler or combi. Combi would be marginally more efficient to run (small one bathroom property) but removes all other heating options like immersion for hot water. Trying to judge what will happen in the lifetime of the new system with the way tariffs/green policies are going is hard, if the gov. put up gas more than electric, heating water off-peak could be cheaper (already within pennies per tank full) Anyone regretting ditching a cylinder, putting one back after a combi expires.
Fit new vented boiler as not necessarily good idea to increase water pressure on old system. Good idea to also replace that cylinder with new unvented hot water cylinder on mains pressure providing the incoming flow rate is good enough. At the same time the low pressure feed to the bathroom can be converted to mains pressure and joined in after the pressure reducing valve for the cylinder to ensure an equal pressure on hot and cold. At least the big tank will then be gone from the loft. The pipework tidied up. Check the ensuite showers suitability for mains pressure
Hi Nick, thanks for your input. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I agree there is a real risk of introducing higher pressure to the existing pipework.
Hi Alan love the videos. I am not a plumber but love heating technology. I had 10 years of grief with an oil combi boiler. I now have a thermal store which gives mains pressure hot water and can fill a bath in 3 mins!!! My advice purely as a consumer would be think very carefully about getting rid of a hot water storage system. The government want to reduce Co2 and are not if favour of gas existing fossil fuel boilers. I still have a simple condensing oil boiler which works perfectly and have the option of heating my water with electricity . Today I am actually being payed to use electricty!!! look to the future and the way we are going to heat our homes. The replacement for my oil boiler will probably be as air source heat pump. Just my thoughts Alan. Keep up the great videos and love the Model 3 by the way.
Yes Alan the content is great and I am sure many trainees value your advice and experience. The videos are down to earth cover what people want to know. Keep up the good work. cheers Keith.
Hi Keith, thanks for your input. I agree keeping the tank would offer more options for the future, and does give me a backup option to use the immersion, on the other hand I've not used the immersion in 15 years and the tank is over 40 years old, so there are quite a lot of things to consider. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution.
Excellent videos! I have a question: I’m refurbishing a 2 bedroom, 2 bathroom property; shall I install a combi or a system boiler? I want to keep costs as low as possible but at the same time I want good hot water supply to both bathrooms and the kitchen. For example: I don’t want to lose hot water in the bathroom while someone is using the hot water in the kitchen. What’s the best and cheapest option? Thanks 🙏
Not a plumber, just a customer of Worcester Bosch combi. This choice I regret & would never advise or recommend this boiler to anyone. Fitted 3 years ago & there's so many reasons why it would take to much space to add complaints.
I'm in need of a new heating system soon, all electric heating at the moment, I'm not on gas so oil is my only option, do you have any experience with oil combi, or is oil better suited for system boiler? I'll be having new pipework everywhere, overlay ufh downstairs and 4 rads on separate zone upstairs, 1 bath. Thanks in advance for your advice.
.....Hello Allen, My old primatic, indirect system has stopped heating the copper cylinder, can I replace the cylinder with a new one with built in coil exchanger if I also fit a bleed valve on the top pipe from the gas boiler ? Hope you can help, love your vids.
Nobody has mentioned customer wanting to do pipework etc himself. Regardless of skill set could open a can of worms for engineer taking the job on board
Hello sir thank you for good explain but I have one question from long time I watch your vedeio look I learn a lot from u me question is if u have any vedeio make vedeio its me more god combi boiler converter to system boiler it’s possible? As we do systems boiler to combi
Hi Alan Wonder if you could advise me? What would you swap like for like with a Glow Worm Ultimate BF50? Interested in a like for like not a combi...what do you think? Cheers for your ever relevant videos and expertise 👍👍
Depends on a number of things, If you wanted to send me a video I will upload here and try and answer. I need to see things like, Where the gas is? What size, flue location, how is it piped.
Hi Alan I am not a plumber but love your talks I think I should have tried it Bit late now 66 If you ever get time explain low loss headers are they needed or just 2 x tee and why! Keep up good shows
Low loss headers are good where there a multiple zones (inc cylinder) and/or large gas rate boilers. The zones on separate time clocks. The boiler pumps around a loop then the zones tap off this loop, pumping out of the loop then pump back into the loop. The boiler is working on a constant flow through its heat exchanger in a more ideal hydraulic environment. The low loss header can have a pipe stat/sensor to ensure no cycling. The low loss header can be on weather compensation. Using a low loss header means no central wall stat and thermo rad valves on all rads can be used. Each room in 100% independent in its temperature control. I have used them on largish homes using smart pumps and thermo rad valves on all rads. If all rads close off the pump winds down automatically. If all rads valves wind down on all rads, the boiler only pumps through the loop. If loop up to temp the boiler switches out. Does not matter how many thermo rad valves close up, the boiler will always have the right flow through its heat exchanger.
Hi Allen, thank you for putting up such informative videos. Very interesting. I hope if you can help me. I am house owner and confused if I have a Combi boiler or leave the system as it is. Current system - Gravity fed, 10 year old condensing heat only boiler. All working well, no problem. We are planning to upgrade the common bathroom with an extra shower. Thus, removing the hot water tank will give us some extra space in the bathroom (if do not get the space we can still squeeze a shower). So, after the upgrade we will have 1 x existing bath, 1 x new shower and 1 x shower in the en suite. Garden tap water flow is between 20-22 L/min. I have some advise from a local boiler installer and he suggested 35-40 KW combi boiler with small twin shower expansion vessel. My worry is, if my kitchen tap is open and two person are having a shower simultaneously, a) would it reduce the pressure? b) would it reduce the hot water supply. Also, we will have new gas from the meter to the boiler location.
I don't know if this will help, but we had the same system as you. We changed to a fully pumped S plan system. This enabled much more control over the HW and heating to split them out. We also had the hot water tank replaced and had a pumped shower put in. It has been really good.
@@rtyrtyrtyus Hi Rob, I think i have a S plan, as I can control HW and radiator separately, they are turned on the different time of the day via Hive. But for the HW we still need the tank which is taking up space near the bathroom in the airing cupboard. How did you remove the tank? did you just replaced it with a new tank in the loft? or are you are talking S plan on Combi boiler.
@@umi2884 We switched from gravity fed HW which doesn't run off a pump to S plan and switched the HW tank in the airing cupboard to a modern, insulated foam copper tank and plugged a Stuart Turner pump direct to it to feed a shower plus the HW taps. The tank in the loft is still there. We needed the pipes tested to make sure they could take the power of the new central heating pump, plus the gas pipe was leaking so had gas re routed to the boiler in new pipe. Severed the gas pipe in the concrete floor. A HW tank is efficient in an airing cupboard if you time them correct and ensure the thermostat on it works with the boiler. As an energy surveyor, expensive HW with a tank is based on poor timings, not inefficiency. I'm not a fan of combi boilers. Sealed pressure systems are OK for commercial but don't like them for domestic purposes. 2 hours a day for HW stays hot 24 hours, gets to 65 degrees for legionella and costs half keeping it on 24 / 7. I did my checks. And that runs 3 showers for 10 minutes hot, even if you shower 23 hours after the HW cut off and is just about to come on again. Our HW is only 7 kWh of gas a day and does 3 peoples daily showers. Open vented, S plan feed and expansion is efficient if used right.
I have the same question! But more of an if you were doing it for the first time and don't want to regret later on, should i use a combi boiler or a dedicated boiler with a closed system mega flo? A house i'm looking to buy currently had a gas hot air system which is ancient from the home report, the whole house will need major renovations done to make it liveable, hence if there was a time to upgrade the heating system now is the time to do it! again, a combi boiler (standard town pressure, the house is in Erskine so it will be standard mains pressure, not a out in the middle of nowhere type house that uses a dedicated pump) or a dedicated boiler with a maga flo, i tend to side on the mega flo option for pressure and reliability alone, however the house is a 3 bedroom with one bathroom, so there's no massive need for a maga flo? saying that, there is room at the back to extend the house years down the line and maybe add an ensuite onto the master bedroom, but the would a big enough combi boiler be suitable for 2 showers in the future? i suppose if it really came to it a decent electric shower could be used instead?
Nope. First get a combi that can take hot water via the cold inlet. Intergas can do that, amongst others. If having solar PV panels and pre-heat cylinder, no problem. just install the new solar cylinder in the loft or in the existing location later, adjust pipework to suit. That cylinder is old. I would not use that for a solar pre-heat.
Hi Alan hows about a video of the pros and cons of being employed or self employed, I'm employed and earn good money and could earn more but hate the regimental hours and rules. What's it like on the other side???
If possible I would put in a/pressurized cylinder megaflow type. And a system boiler or combi can u run gas out side to loft then all pipes/would work .hope condense would be easy .
If the old boiler complies with regs and is safe to use, the open vent cylinder is leak free, all valves work, simple if its not broken leave well alone. end of story.
Except it will cost a fortune to run and will not give high pressure showers unless an appalling, and expensive, house shaking, power shower pump is fitted. It is at the end of its live span, as is the cylinder, so now prone to breakdown. Going for a state of the art combi for e.g., will drop his gas bills by 25-30%. The bigger the house (4 beds) and the more it is poorly insulated (as are most) the bigger the savings, as they consume more gas. Then figure out the return on investment. He is a competent tradesman able to do most of the work himself. While he is fit and has the money, it is good idea to replace antiquated equipment that is expensive to run, and get out of the 1970s.
Keep the old boiler, just sort out the bathroom plumbing. I keep my old Baxi back boiler going and it is far better than this modern junk. But on the other hand my next door neighbors had a like-for like new wall hung open vented boiler (Glow Worm) installed and it cost £1800 which included the fitting of a condensate pipe to an outside drain and a full system clean and flush.
I recently went from a vented system boiler to a vv100w 35kw combi. Heating engineer tried to persuade me to stay on the system boiler and just replace like for like. My header tank was c. 1.25m head above the shower head. I calculated out the head pressure set against flow rates and mains pressure. Armed with following Allen and his reasoning on his videos i stuck with my evaluation and told my heating engineer I wanted the Viessmann vittodens 100w 35kw to max out on hot water capacity. On test i got 12 litres a min at delta 25 c not the 14 at delta 35. That said the shower is a new beast on both temperature and pressure/flow. Now the bad bit. I did the wet work removing the system bits. Repaired the wall it was hung on. Gas was fine 22mm with a 3m run to the meter heating engineer did the gas and boiler install. Delighted with the Viessmann performance. Added Honeywell evohome TRVs etc. love the control. Economy to be determined but has to be an improvement just a Q on how much.. I am not a heating engineer though I am an engineer and scientist so able to evaluate these things. Allen's videos worth trawling through for his words of wisdom and his experience. It was Allen that put me onto Viessmann as I was thinking worcesterbosch before I watched Allen's videos. Strange I still watch them after my heating is sorted - he is not even that pretty....🤐 sorry Allen hope you are not too sensitive for Scottish humour and back handed compliments.
I would either suggest keeping it as a heat only or system boiler and probably find out more about the length of the 15mm gas supply. Maybe a test on the existing boiler would give some idea as least (but not conclusive) Having said that, with the small hot water demand, providing the incoming water pressure and flow rate is decent, maybe a combi would be beneficial. Just bare in mind that if you seal the system, you are risking possible leaks on any weak pipework.
Hi, thanks for your input. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I agree there is a real risk of introducing higher pressure to the existing pipework. The house floor is beam and block, with half of it covered with a wooden sub floor on 3" beams, the other half (kitchen and utility) sand and cement screed with pipes buried within. So the gas run is about 9M, but 3M or so passes through the screed so not easy to replace. There is the option of an external pipe run as boiler is on the same side of house as the gas meter, but I'm not really keen one external pipes.
Hi Allen/Dave. I'd be considering a storage combi or normal combi if low water use installed in the loft Assuming there's a gable end or even in the airing cupboard. Get the gas through the house up there. Convert the bathroom supply to mains etc too 👍
@@AllenHart999 me neither but was considered the noise/vibrating boiler if installed on internal walls I'm airing cupboard. So a brick gable end might be a better option
My first question to the customer would be how much hot water do you use a week aprox? as if this is a lot it will be cheaper and more energy efficiant in the long run to stay away from a combi. The next question would be water pressure and volume of water at the house. as a unvented clinder may be an option.
Hi Robert, thanks for your comment. I don't use a real lot of hot water, one shower a day, 4 or 5 bath full a week and a couple of wash loads. The house is empty during the day when I am at work, so at the moment I do seem to be keeping a tank of hot water just sat there. The water pressure and flow is good, but I haven't had it measured so can't give you a figure.
@@DaveC3350 Hi Dave first can i say i am not in a position to do your Job i am in Manchester. But quite a few years ago now I did an energy efficiancy corse and what i learned and what I allways say to my customers is if you are having more than 3 baths a week then it will be more efficiant to look at stored hot water, unvented ect. Comb/Boilers are great but use a lot of gas when generating hot water . A bath can hold anywhere from 150-300ltrs of water and if you times that by your 5 a week, that is a lot of gas usage aprox £1.10-£1.30 per bath, over the year £400-£450. Thant does not include any heating. With stored hot water you can have mains pressure hotwater all the time at I would say a quarter of the cost. But it is more expensive to install. Just my humble opinion. sorry for the spelling hope this helps you to decide. Rob RMB Plumbgas Ltd
Interesting video as I have the same dilemma. Currently I have an open vent system like Dave in this video. British Gas quoted me £2500 to replace with another open vent boiler. Since then I’ve often wondered about moving to a combi?
Combi,s only real plus is that they are ideal if you have a lack of space. If you do fit one then I would install an electric shower. The reason being is that if the boiler went down/packed up you have hotwater. For me I am not a lover of Combi,s.
A high flow combi will do it. *No need for tanks and cylinders in the averages British home these days.* Combis can do the lot., providing the main water flow & pressure is fine. OK, if it was my house what would I do. ♦ Get rid of the cylinder and loft tank. ♦ Intergas Xtreme combi giving over 14 litre/min. Great for a one bath house. Not cheap but quality with only 4 moving parts. Super reliable. Built like tanks. ♦ They are _quiet_ in operation. ♦ The Extreme modulates the burner to a very low kW rating. This avoids/vastly reduces inefficient boiler cycling. ♦ Have an outside weather compensator sensor fitted - £25-£30. Intergas come with weather compensation as standard. ♦ Have an _Opentherm_ stat on the wall. ♦ Opentherm stat and outside sensors keep the burner as low as possible _modulating_ the burner down as much as possible - the Extreme burner modulates very low. If the house only need an input of say 3 kw, the burner just ticks over slowly and silently. No inefficeint on-off. ♦ Uprate the gas pipe to 22mm all the way. Find out where the 22mm of the gas pipe ends, there may not be a lot of 15mm pipe there, as the existing boiler is quite a high gas rate. If the cooker pipe is on a separate pipe direct from the meter and is adjacent, this can be teed into the 15mm gas pipe at the boiler creating a gas ring, similar to an electric ring, which may prevent problems in getting a larger bore pipe to the boiler. ♦ The intergas can still be open vented, in keeping the small F&E tank in the loft. The only combis that can be open vented. I would make it a sealed system - unless the rads are very old. High pressures may pop them, then more needless expense. If old, it may be worth keeping the F&E tank until new rads are fitted then get rid of it making it sealed (pressurised). ♦ Replace main water stop tap with a full bore tap to improve water flowrate. ♦ Take combi hot draw off pipe up to cylinder position connecting onto hot pipe there. ♦ Tee onto hot pipe in room where combi is, so hot water does not come from upstairs to downstairs. ♦ As Allen says, connect cold main in loft to old cold feed from tank in loft. ♦ Fit a magnetic/solids filter. ♦ Fit scale reducer. See my post. Could also fit the Intergas smart phone control system, if that floats your boat. Based on what I gleened from the vid. ♦ You will not look back. I would fit either the Intergas or a Navien as second choice. The Navien gets the outside temperature for the control system off the cell phone network so no wiring or outside sensor to be fitted. A touch screen control panel. Navien are the biggest combi makers in the world. Quality product.
I found that the house has a bathroom and an ensuite. I assume only a shower in the ensuite. If it was mine. A Viessmann 111 stored water combi as 1st choice. A quality product that will deliver the hot water providing the mains flow and pressure is adequate and the pipework is sized and designed properly (Have a _dedicated_ 22mm pipe from the stopcock to the combi). Saves space by removing tank and cylinder. Can have heat in the airing cupboard by having a small rad in there on the back wall. Alternative: ♦ An Intergas Rapid 32kW combi (well priced) connected to the *showers* and hot sink tap in kitchen, to give high pressure showers and instant hot water at the kitchen tap. ♦ Try to have Handsgrohe Raindance type of shower heads (aerated) at they consume far less water. ♦ To fill the bath and serve the rest of the hot water, a low pressure combination cylinder (cold tank incorporated). like this: www.tradeplumbing.co.uk/gle...ffz_Dp2is5Px0Bqxmbst9EaAl1zEALw_wcB&sel=47082 ♦ Cylinder can provide hot water to the bath and all other hot outlets. This will be heated by the combi as a system boiler would do. ( a combi is a system boiler with a water section). ♦ Combination cylinder can be in the existing cylinder's location, or in the loft - providing it can get up there and it is supported well enough. ♦ Having a vented combination cylinder means no expensive pressure valves, annual service, explosion risk, expensive G3 approved plumbers only to work on it, as on unvented cylinders. ♦ I would have the Intergas Rapid on a vented loft F&E tank as pressurising the rad circuit may bust a few old rads giving more expense. When rads are replaced pressurise the system removing the F&E tank. ♦ So, the cylinder can be off, except when you want baths or hot water at the bathroom basin taps (very rare). Then lower running costs, as you are not heating hot water unnecessarily.
@@johnburns4017 Hi John, thanks for your additional reply much appreciated. I've been a bit busy with work, so only just collating everyone's views and recommendations. I agree with your thoughts and points of caution, there is quite a lot to take into account. I will let everyone know what I choose as soon as I can via Allen. The biggest pain is going to be the gas pipe, there is a possible route through, but its the living room floor up and then chopping out in the under stairs screed to get the pipe through! Thanks again for your valuable input, Cheers, Dave.
Hi Alan if flow and pressure on the mains is up to scratch, I'd be going 35kw combi, upgrade the gas I tend to go 28mm to within a couple of metres of the boiler if possible. Decent manufacturer flush the system well, allow for an electrolytic or magnetic descaler on the mains, a good central heating filter and always fit a shock arrestor as standard. Another good video mate you're like the Steven Spielberg of the plumbing and heating industry ha ha 👍
Sorry Richard should of explained myself better, what will do a lot will do a little, obviously I wouldn't fit a 35kw in a flat or terraced property, but looking at the gentleman's video he said he'd also got an en suite besides his bathroom and kitchen so potential for three hot water draw offs simultaneously. The heating not a problem, most manufacturers you can adjust that load through the settings menu. It was purely through my experience and knowledge I suggested the 35kw option and just my own opinion, I've been to plenty of 24kw combis in 4 bedroom, 2 bathroom and ensuite properties and well say no more
Hi Mark, thanks for your input. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I haven't considered a shock arrestor, so will put that on my list of items. The water pressure here is quite good with a good flow, but I haven't had it measured so can't give you a figure.
@@DaveC3350 Hi Dave I'm guessing you know a decent plumber/gas engineer in your neck of the woods to test the pressure, it's just a guage you screw on to a 3/4 bsp thread either outside tap or washing machine tap will be fine, if it's over 7bar it will need a pressure reducing valve but it's very rare the water mains will be over that👍
Never consider a Combi boiler if you have the option, why? The amount of fresh water you will waste whilst waiting for hot water to come through (not to mention frustration) might be acceptable in some parts, but having lived in areas of the country often suffering a water shortage you can bet you right arm water costs will rise in future. Im not registered plumber, just engineer, but for my former farmhouse i designed and installed unvented system with large water cylinder. Always had virtually instant hot water in 3 bathrooms, including showers. Sold property 6 years later, never had single problem during interim.
Hi, thanks for your reply. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I agree I should consider water wastage, as I've not had any real hands on experience of a combi, so it would be good to get an idea of how many litres need to pass through the boiler before the output reaches temperature?
Yes and Yes. I did a live video to ask for feedback or input into the next video but it ended up been over 2 hours long 😂No body wants to watch me for 2 hours
Think a Baxi 836 fitted in place of existing with up grade to gas supply or maybe fitted in cylinder cupboard upstairs .Only small family so why go to extreme expense or unvented or even keep open vented cylinder for small hot water requirement Definitely not a Worcester combi tho Richard Williams been in trade now for 55 years
Hi Richard, thanks for your reply. I've been a bit busy with work, so only just collating everyone's views and recommendations. I agree with your thoughts, and will let everyone know the outcome as soon as I can. Cheers, Dave.
Combi and existing hw tank, use the combi to feed the shower in the ensuite and the existing tank for the bath. If they don't mind juggling by filling Bath first and then someone using shower once full then straight combi. And replace bath and shower valves with thermostatic ones.
BTW the HW relay works the opposite way around on a intergas so on /closed contact is off. Also I have a tank stat and room stat to override the Internet ones just in case they loose connection.
Combi nothing but trouble, fit like for like with a cold water mains feed to the bathroom sink tap/ toilet along with a thermostatic mixer valve for the hot side of the sink.
Never a combi boiler for me system boiler and megaflow if u have the water flow. Mains water everywhere no pumps and if u have a problem with your boiler u can turn immersion on for hot water.
Megaflo? Are you serious? The one with the internal air bubble that dissolves and the internal plastic baffle disintegrates? Made by Satan himself. Then all the unvented pressure reducing and protection valves, that when they fail cost and arm and a leg to replace. That also need an annual service with only G3 approved men to work on them? Give them a wide berth. Fit one of these (low pressure) with a combi heating it with _only_ the high pressure shower off the combi. It does exactly the same as an unvented cylinder, not costing a fortune to run. And will not explode. www.tradeplumbing.co.uk/gle...ffz_Dp2is5Px0Bqxmbst9EaAl1zEALw_wcB&sel=47082
Hi Alan my god this gentleman has confused me what's the story here first of all how many bedrooms bathrooms and and for a start no combination for a house only for flats and then take it from there confusing video long story I think there is a catch to this the way he's talking he knows a bit about this thank you
Hi, thanks for your comment. The video was originally intended just for Allen, but he thought by sharing it it would help me with my decision / system choice. The property is a detached house, 4 bedrooms, one bathroom, one en-suite, living room-dining room and a kitchen. I'm an electrician by trade, and wired up many systems and also done quite a lot of plumbing in the past 40 years for myself, so I am familiar with the various system choices, just struggling to decide what is best.
@@johnburns4017 Hi John, 1 shower in en-suite, 1 bath with show mixer (only used to rinse down), other than that typical 4 bed house. We are in a hard water area, so I will add a scale reducer to my list. Thanks again for your input. Cheers, Dave.
Combi boiler are very finicy. No really competent engeneers in uk who can maintain it either. The good old oil radiators on electricity is way better and cheaper
I like the concept of this video allan, also helps the client to understand what we reccommend is for best results not always guaranteed workmanship but by doing it here, i believe he would avoid a cowboy coming in and making a disaster of it 👍
Great advice! Thanks!
I am considering replacing a 30+ year old Potterton Kingfisher RS 50 CAT 1N boiler.
The hot water tank iis gravity fed with an overhead tank.
Thermostatically controlled power shower require such a tank.
OJ Gas & Heating (a WB Accredited installer!) said that he will fit a combi, remove the hot water tank and replace the shower with another type.
After watching videos and reading the forums, I am planning to fit a Greenstar 12/15Ri boiler.
I can not fathom why a WB Accredited installer recommended fitting a combi
System boiler + unvented cylinder is always my preference.
Gas - Viessmann
Oil - Grant
Cylinder - Megaflo or Range Tribune XE
I’m a qualified gas engineer enjoy your videos keep up good work, I would personally would install a combination boiler for me I prefer ideal logic or I would install a Worcester as they are good boilers if install correctly all depends on how much they want to spend!!
Thanks for the tips!
Combis are so convenient.....and easy to install....but to me a Rolls Royce system is a system boiler with an unvented cylinder as long as you have space for the cylinder. No header tank is needed, but the biggest benefit is that if it breaks down you still have hot water via the Immersion, and you use a fan heater for temporary heat. If a combi breaks down its a crisis, if a system boiler breaks down its an inconvenience. I had two Elans, one installed in 1983 and the other (new house) in 1985. I have a heat only Logic on Y plan in current house. It was an Ideal turbo 2 condenser previously and that gave very little trouble over 25 years. As to make of boiler...just choose a reputable make with a decent guarantee. I think you are aware of the current best buys.
Thank you. Very good answer. 👍👍👍
As a company and incredited installers, we always fitted Worcester's , but many years back I fitted an Ideal for a customer and was really impressed. Long gone are the regular burnt out pcb,'s of old. I fitted a logic + in my house five years ago and can't fault it. Much better price than a Worcester too
Hi Allen i am a GSI on the East coast i think in this situation i would be advising another modern open vent boiler , and replace the old cylinder afterall it is as old as the boiler ? the pipework can then be tidied up in the airing cupboard , the radiator valves would need changing and throughly clean the system and fit a magnetic filter , clean out the storage tanks and replace the ball valves, and upgrade all the contols to a Honeywell s plan system . I would not want to pressurise the old pipework and exsisting system changing like for like is the safer option . Regards Wayne
Hi Wayne, thanks for your input. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I agree there is a real risk of introducing higher pressure to the existing pipework.
Wow, back to the 70s! Do you provide the flared pants as well? :) An intergas can be run open vented with an F&E tank. They advise to keep the internal pressure vessel connected, even though open vented. Keeps local pressure away from heat exchanger A few years back fitted an Intergas to a 40 years old open vent system. Kept the F&E tank to avoid the rads popping. Working brilliantly since. See my post.
Both my hot and cold supply into the bathroom are tank fed ,it's a bungalow and there is no problem with the cold pressure,I am just wondering if there is a problem with say the gate valve not fully open or sheared so you are moving the wheel head but the gate is not opening ,I have had this a couple of times with old gate valves obvious if it's snaped when you have closed the valve for some reason not so if it is half way open.The chap is obviously quiet handy so moving to a condensing boiler would knock that one on the head. There might well be an issue with spare parts for the old boiler although a lot of stuff is still available as it was common to many boilers . If you must I would change like for like ,He can continue to maintain everything but the boiler.but consider you are swapping these new boilers every 10 years he would be on his fourth condensing boiler now ,and they make out this is progress!
Hi John thanks for your input. The cold feed to the bathroom works fine with good pressure, I just want drinking water at the sink tap rather than tank fed water. The old boiler has been great, but is really noisy some days on startup (sounds like a Jumbo coming in to land). I was advised it was the heat-exchanger, but these have been obsolete for 8 years plus, so I running on borrowed time really, and its also a bit of a gas guzzler by modern standards. So I'm looking to upgrade over the summer.
Hot water tanks are only inefficient if old and you keep the hot water on 24 hours. I am an energy surveyor and modern tanks are fine if you only heat once a day. It can easily do three 10 minute showers. Heat for 2 hours a day, enough to get to shut of temp of 60 Celsius and just have that repeat daily. If you need more showers, top up once for an hour. It just needs some planning. Keeping a water tank on 24 hours costs twice that as once a day, purely because of heat loss from the tank. Having said that, with more insulation, the issue of timing the water to come on is less of an issue and doesn't affect your gas usage. I've also seen some bare copper cylinders in my time and the cupboard it is in is a sauner.
Thank You
This is a great video Allan well done.
I would go for Ideal combi 35kw.
Obviously I would powerflush the system first, then I would definitely upgrade the gas pipe that’s very very important running the right size from the meter all the way to the boiler taking in consideration other gas appliances in the house, pressure loss less than 1mbar.
With the clean system I would install a 22mm fernox filter, acidic neutraliser and descaler on the mains. By installing the combi you would get rid of both tanks gaining some space. Like Allan said there might be a need for changing the shower because of the mains pressure.
Hi Alan, I'm also an Electrician, I installed an open vent system powered by a Potterton Netaheat Mk IIF in my house back in 1984 which is still going strong - no problems.
Of course the boiler will eventually have to be replaced which will put me in the same situation as Dave here.
But I will be staying with an open vent system. Why not? reliable! cheaper! no messing around the place altering pipework etc!
I don't like Combi boilers, I've heard too many complaints about them from customers whilst I was working for a central heating company, although that was quite a while ago and they no doubt have got better.
Anyway I thought I would throw that in here as a different outlook to all the Combi fanboys here.
Love your videos!
It’s all about how it’s installed, I have never heard a complaint about a boiler that’s been specified correctly, I wouldn’t have an open vent in my own house but sometimes there are no choice.
Viessmann 111 W Storage Combi or Saunier Duval Combi ( Vaillant) I think and I think the old copper and all can deserve to remove and replace to bew MLCP manifold system... I know is very pricey job but worth on long run... Nice video Allan
He only has one bathroom, so I would say no to the stored water combis. Two bathrooms? Then yes.
Hmm As a non Plummer I would want to check out the pipe work in the bathroom first to see just what was put in , and do a flow test , if it was more than 15 on the water and then do a gas feed check. the tank being old should be replaced given the cost of doing both , given the limited water usage , with just 1 bathroom I would say go high end combi or an in between such as a vittadenns 111f that should cope with the property for when the kids visit. If there are plans to add a second bathroom/on suite I would say go system and free up the loft
Hi Alan
Assuming there is good water flow, customer is ok spending a little bit more I would go with a 30kw to 35kw ideal logic max combi. It should fit inside the cupboard unless thee is a better place for it. It gives enough hot water flow and you can sort out the bathroom at the same time killing 2 bird and all that.
Phill.
Cheers Phil, thanks for your input.
I'd loved to have had my new English oil boiler fitted, but the guy ran off with thousands of our pounds, left us with a new boiler that won't work with the French domestic heating oil, so no one will touch it. So in answer to your question, what system to have. I'd say, just one that works would be great. BTW, I love your videos. Invalid living in France.
My name Ismael Pedro, Plumber/heating engineer I love you videos, its really helpful, keep posting I really appreciated ur wrk
I've got a copper cylinder with a potterton condensing Gold H15,whilst my plumber was here exchanging 2 automatic air vents he told me that my pump is now discontinued because of EU regulations so if it goes wrong I'm screwed is that correct because my system is gravity fed fully pumped system,do you think there is a pump I can purchase allowing me to continue with my present boiler which has just reached its tenth year,I googled the manufacturers and they said that boiler should run efficiently for a minimum of 15 years,my plumber did it's tenth year check on it 2 weeks ago and he said his readings were good
an interesting video, i think this could be a very popular format for you Allen, get to see what issue someone has then get your expert opinion on it.
For me system boiler every time, Viessmann 200 boiler, Viessmann unvented tank, and weather compensation
Working on one Monday.
2 bathrooms
depending on incoming mains flow rate i would say
170 lt unvented
18 to 24 kw system boiler
100% machine flush
I'm going to update my open vent system this summer, it's ancient but going strong. The biggest dilemma for me is hot water cylinder with system boiler or combi. Combi would be marginally more efficient to run (small one bathroom property) but removes all other heating options like immersion for hot water. Trying to judge what will happen in the lifetime of the new system with the way tariffs/green policies are going is hard, if the gov. put up gas more than electric, heating water off-peak could be cheaper (already within pennies per tank full) Anyone regretting ditching a cylinder, putting one back after a combi expires.
Fit new vented boiler as not necessarily good idea to increase water pressure on old system. Good idea to also replace that cylinder with new unvented hot water cylinder on mains pressure providing the incoming flow rate is good enough. At the same time the low pressure feed to the bathroom can be converted to mains pressure and joined in after the pressure reducing valve for the cylinder to ensure an equal pressure on hot and cold. At least the big tank will then be gone from the loft. The pipework tidied up. Check the ensuite showers suitability for mains pressure
Hi Nick, thanks for your input. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I agree there is a real risk of introducing higher pressure to the existing pipework.
Hi Alan love the videos. I am not a plumber but love heating technology. I had 10 years of grief with an oil combi boiler. I now have a thermal store which gives mains pressure hot water and can fill a bath in 3 mins!!! My advice purely as a consumer would be think very carefully about getting rid of a hot water storage system. The government want to reduce Co2 and are not if favour of gas existing fossil fuel boilers. I still have a simple condensing oil boiler which works perfectly and have the option of heating my water with electricity . Today I am actually being payed to use electricty!!! look to the future and the way we are going to heat our homes. The replacement for my oil boiler will probably be as air source heat pump. Just my thoughts Alan. Keep up the great videos and love the Model 3 by the way.
Thank you so much Keith for still watching after all this time. Have my video’s improved 😂
Yes Alan the content is great and I am sure many trainees value your advice and experience. The videos are down to earth cover what people want to know. Keep up the good work. cheers Keith.
Hi Keith, thanks for your input. I agree keeping the tank would offer more options for the future, and does give me a backup option to use the immersion, on the other hand I've not used the immersion in 15 years and the tank is over 40 years old, so there are quite a lot of things to consider. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution.
Excellent videos!
I have a question: I’m refurbishing a 2 bedroom, 2 bathroom property; shall I install a combi or a system boiler? I want to keep costs as low as possible but at the same time I want good hot water supply to both bathrooms and the kitchen. For example: I don’t want to lose hot water in the bathroom while someone is using the hot water in the kitchen. What’s the best and cheapest option? Thanks 🙏
Allen your videos get better and better love watching your channel honest advice as always. I'd go with combi a baxi.
Hi Ricky you are so kind. Thank You.
Not a plumber, just a customer of Worcester Bosch combi. This choice I regret & would never advise or recommend this boiler to anyone. Fitted 3 years ago & there's so many reasons why it would take to much space to add complaints.
I'm in need of a new heating system soon, all electric heating at the moment, I'm not on gas so oil is my only option, do you have any experience with oil combi, or is oil better suited for system boiler? I'll be having new pipework everywhere, overlay ufh downstairs and 4 rads on separate zone upstairs, 1 bath. Thanks in advance for your advice.
.....Hello Allen, My old primatic, indirect system has stopped heating the copper cylinder, can I replace the cylinder with a new one with built in coil exchanger if I also fit a bleed valve on the top pipe from the gas boiler ? Hope you can help, love your vids.
Nobody has mentioned customer wanting to do pipework etc himself. Regardless of skill set could open a can of worms for engineer taking the job on board
Customers that have watched too much UA-cam are a nightmare.
Defo go for a baxi combi, may need to check 15mm gas pipe at the source if can be changed
Needs to be 22mm on Baxi👍
Hello sir thank you for good explain but I have one question from long time I watch your vedeio look I learn a lot from u me question is if u have any vedeio make vedeio its me more god combi boiler converter to system boiler it’s possible? As we do systems boiler to combi
Hi Alan
Wonder if you could advise me? What would you swap like for like with a Glow Worm Ultimate BF50? Interested in a like for like not a combi...what do you think?
Cheers for your ever relevant videos and expertise 👍👍
Depends on a number of things, If you wanted to send me a video I will upload here and try and answer. I need to see things like, Where the gas is? What size, flue location, how is it piped.
Hi Alan I am not a plumber but love your talks
I think I should have tried it
Bit late now 66
If you ever get time explain low loss headers are they needed or just 2 x tee and why!
Keep up good shows
Low loss headers are good where there a multiple zones (inc cylinder) and/or large gas rate boilers. The zones on separate time clocks. The boiler pumps around a loop then the zones tap off this loop, pumping out of the loop then pump back into the loop. The boiler is working on a constant flow through its heat exchanger in a more ideal hydraulic environment. The low loss header can have a pipe stat/sensor to ensure no cycling. The low loss header can be on weather compensation.
Using a low loss header means no central wall stat and thermo rad valves on all rads can be used. Each room in 100% independent in its temperature control. I have used them on largish homes using smart pumps and thermo rad valves on all rads. If all rads close off the pump winds down automatically. If all rads valves wind down on all rads, the boiler only pumps through the loop. If loop up to temp the boiler switches out. Does not matter how many thermo rad valves close up, the boiler will always have the right flow through its heat exchanger.
Hi Allen, thank you for putting up such informative videos. Very interesting. I hope if you can help me. I am house owner and confused if I have a Combi boiler or leave the system as it is. Current system - Gravity fed, 10 year old condensing heat only boiler. All working well, no problem. We are planning to upgrade the common bathroom with an extra shower. Thus, removing the hot water tank will give us some extra space in the bathroom (if do not get the space we can still squeeze a shower). So, after the upgrade we will have 1 x existing bath, 1 x new shower and 1 x shower in the en suite. Garden tap water flow is between 20-22 L/min. I have some advise from a local boiler installer and he suggested 35-40 KW combi boiler with small twin shower expansion vessel. My worry is, if my kitchen tap is open and two person are having a shower simultaneously, a) would it reduce the pressure? b) would it reduce the hot water supply. Also, we will have new gas from the meter to the boiler location.
I don't know if this will help, but we had the same system as you. We changed to a fully pumped S plan system. This enabled much more control over the HW and heating to split them out. We also had the hot water tank replaced and had a pumped shower put in. It has been really good.
@@rtyrtyrtyus Hi Rob, I think i have a S plan, as I can control HW and radiator separately, they are turned on the different time of the day via Hive. But for the HW we still need the tank which is taking up space near the bathroom in the airing cupboard. How did you remove the tank? did you just replaced it with a new tank in the loft? or are you are talking S plan on Combi boiler.
@@umi2884 We switched from gravity fed HW which doesn't run off a pump to S plan and switched the HW tank in the airing cupboard to a modern, insulated foam copper tank and plugged a Stuart Turner pump direct to it to feed a shower plus the HW taps. The tank in the loft is still there. We needed the pipes tested to make sure they could take the power of the new central heating pump, plus the gas pipe was leaking so had gas re routed to the boiler in new pipe. Severed the gas pipe in the concrete floor. A HW tank is efficient in an airing cupboard if you time them correct and ensure the thermostat on it works with the boiler. As an energy surveyor, expensive HW with a tank is based on poor timings, not inefficiency. I'm not a fan of combi boilers. Sealed pressure systems are OK for commercial but don't like them for domestic purposes. 2 hours a day for HW stays hot 24 hours, gets to 65 degrees for legionella and costs half keeping it on 24 / 7. I did my checks. And that runs 3 showers for 10 minutes hot, even if you shower 23 hours after the HW cut off and is just about to come on again. Our HW is only 7 kWh of gas a day and does 3 peoples daily showers. Open vented, S plan feed and expansion is efficient if used right.
@@rtyrtyrtyus Thank you so much. This is exactly the answer I needed.
I have the same question! But more of an if you were doing it for the first time and don't want to regret later on, should i use a combi boiler or a dedicated boiler with a closed system mega flo? A house i'm looking to buy currently had a gas hot air system which is ancient from the home report, the whole house will need major renovations done to make it liveable, hence if there was a time to upgrade the heating system now is the time to do it! again, a combi boiler (standard town pressure, the house is in Erskine so it will be standard mains pressure, not a out in the middle of nowhere type house that uses a dedicated pump) or a dedicated boiler with a maga flo, i tend to side on the mega flo option for pressure and reliability alone, however the house is a 3 bedroom with one bathroom, so there's no massive need for a maga flo? saying that, there is room at the back to extend the house years down the line and maybe add an ensuite onto the master bedroom, but the would a big enough combi boiler be suitable for 2 showers in the future? i suppose if it really came to it a decent electric shower could be used instead?
Liam Scott if you want to send a full video I would be happy to upload it
Sealed system for sure, sounds like a combi would best suit him. Old system could be an old one pipe C plan needing a complete change?
Do you consider to install solar panels in the future? If so you need to keep tank...
Nope. First get a combi that can take hot water via the cold inlet. Intergas can do that, amongst others. If having solar PV panels and pre-heat cylinder, no problem. just install the new solar cylinder in the loft or in the existing location later, adjust pipework to suit. That cylinder is old. I would not use that for a solar pre-heat.
Hi Dave Chapman - what did you opt for in the end sir??
I am intrigued as well.
Hi Alan hows about a video of the pros and cons of being employed or self employed, I'm employed and earn good money and could earn more but hate the regimental hours and rules. What's it like on the other side???
Sounds like a great idea 💡 Thanks
If possible I would put in a/pressurized cylinder megaflow type. And a system boiler or combi can u run gas out side to loft then all pipes/would work .hope condense would be easy .
If the old boiler complies with regs and is safe to use, the open vent cylinder is leak free, all valves work, simple if its not broken leave well alone. end of story.
Except it will cost a fortune to run and will not give high pressure showers unless an appalling, and expensive, house shaking, power shower pump is fitted. It is at the end of its live span, as is the cylinder, so now prone to breakdown.
Going for a state of the art combi for e.g., will drop his gas bills by 25-30%. The bigger the house (4 beds) and the more it is poorly insulated (as are most) the bigger the savings, as they consume more gas. Then figure out the return on investment.
He is a competent tradesman able to do most of the work himself. While he is fit and has the money, it is good idea to replace antiquated equipment that is expensive to run, and get out of the 1970s.
Funny north of the Midlands Ideal and Baxi and Ravenheat.South of Midlands Worcester and Vaillant the great north south divide 😂
wonder how many people, in 35 years time, will be using the boiler they use today??
I'd advise a system boiler and unvented cylinder. It just don't get better. Than that.
Thank you for the comment.
Combi for me assuming flow ok, but new gas run needed or as min danage uograde to unvented and heat only boiler - can logics be run on 15mm gas? 🤔
Keep the old boiler, just sort out the bathroom plumbing. I keep my old Baxi back boiler going and it is far better than this modern junk. But on the other hand my next door neighbors had a like-for like new wall hung open vented boiler (Glow Worm) installed and it cost £1800 which included the fitting of a condensate pipe to an outside drain and a full system clean and flush.
i agree if it aint broke whats the point, and as for a combi it would take ages with the pipe runs to get any hot water to upstairs
If the combi breaks down, you have nothing; no heat no hot water. Shower flow rate could be less, something to consider.
I recently went from a vented system boiler to a vv100w 35kw combi. Heating engineer tried to persuade me to stay on the system boiler and just replace like for like. My header tank was c. 1.25m head above the shower head. I calculated out the head pressure set against flow rates and mains pressure. Armed with following Allen and his reasoning on his videos i stuck with my evaluation and told my heating engineer I wanted the Viessmann vittodens 100w 35kw to max out on hot water capacity. On test i got 12 litres a min at delta 25 c not the 14 at delta 35. That said the shower is a new beast on both temperature and pressure/flow. Now the bad bit. I did the wet work removing the system bits. Repaired the wall it was hung on. Gas was fine 22mm with a 3m run to the meter heating engineer did the gas and boiler install. Delighted with the Viessmann performance. Added Honeywell evohome TRVs etc. love the control. Economy to be determined but has to be an improvement just a Q on how much.. I am not a heating engineer though I am an engineer and scientist so able to evaluate these things. Allen's videos worth trawling through for his words of wisdom and his experience. It was Allen that put me onto Viessmann as I was thinking worcesterbosch before I watched Allen's videos. Strange I still watch them after my heating is sorted - he is not even that pretty....🤐 sorry Allen hope you are not too sensitive for Scottish humour and back handed compliments.
I would either suggest keeping it as a heat only or system boiler and probably find out more about the length of the 15mm gas supply. Maybe a test on the existing boiler would give some idea as least (but not conclusive)
Having said that, with the small hot water demand, providing the incoming water pressure and flow rate is decent, maybe a combi would be beneficial. Just bare in mind that if you seal the system, you are risking possible leaks on any weak pipework.
Thank you for the comment.
Hi Allan
My name is faruk i am gas engineer on this situation i will install vitodens 100w 30kw combi
Regards
Faruk
Hi, thanks for your input. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I agree there is a real risk of introducing higher pressure to the existing pipework. The house floor is beam and block, with half of it covered with a wooden sub floor on 3" beams, the other half (kitchen and utility) sand and cement screed with pipes buried within. So the gas run is about 9M, but 3M or so passes through the screed so not easy to replace. There is the option of an external pipe run as boiler is on the same side of house as the gas meter, but I'm not really keen one external pipes.
Hi Allen/Dave. I'd be considering a storage combi or normal combi if low water use installed in the loft Assuming there's a gable end or even in the airing cupboard. Get the gas through the house up there. Convert the bathroom supply to mains etc too 👍
Oh and seriously consider the ideal vogue boilers👍
I am not keen on installing boilers in lofts but thank you so much for the comments.
@@DBPLUMBING Ideal Vogue is a great boiler. Thanks.
@@AllenHart999 me neither but was considered the noise/vibrating boiler if installed on internal walls I'm airing cupboard. So a brick gable end might be a better option
My first question to the customer would be how much hot water do you use a week aprox? as if this is a lot it will be cheaper and more energy efficiant in the long run to stay away from a combi.
The next question would be water pressure and volume of water at the house. as a unvented clinder may be an option.
Hi Robert, thanks for your comment. I don't use a real lot of hot water, one shower a day, 4 or 5 bath full a week and a couple of wash loads. The house is empty during the day when I am at work, so at the moment I do seem to be keeping a tank of hot water just sat there. The water pressure and flow is good, but I haven't had it measured so can't give you a figure.
@@DaveC3350 Hi Dave first can i say i am not in a position to do your Job i am in Manchester. But quite a few years ago now I did an energy efficiancy corse and what i learned and what I allways say to my customers is if you are having more than 3 baths a week then it will be more efficiant to look at stored hot water, unvented ect. Comb/Boilers are great but use a lot of gas when generating hot water . A bath can hold anywhere from 150-300ltrs of water and if you times that by your 5 a week, that is a lot of gas usage aprox £1.10-£1.30 per bath, over the year £400-£450. Thant does not include any heating. With stored hot water you can have mains pressure hotwater all the time at I would say a quarter of the cost. But it is more expensive to install.
Just my humble opinion. sorry for the spelling hope this helps you to decide.
Rob RMB Plumbgas Ltd
Interesting video as I have the same dilemma. Currently I have an open vent system like Dave in this video. British Gas quoted me £2500 to replace with another open vent boiler.
Since then I’ve often wondered about moving to a combi?
Feel free to send me a fully detailed video and I will add it on here and others will also help you. Thanks.
Combi,s only real plus is that they are ideal if you have a lack of space. If you do fit one then I would install an electric shower. The reason being is that if the boiler went down/packed up you have hotwater. For me I am not a lover of Combi,s.
Firstly id always do a Heatloss calc.
Then whats your budget?
A high flow combi will do it. *No need for tanks and cylinders in the averages British home these days.* Combis can do the lot., providing the main water flow & pressure is fine.
OK, if it was my house what would I do.
♦ Get rid of the cylinder and loft tank.
♦ Intergas Xtreme combi giving over 14 litre/min. Great for a one bath house. Not cheap but quality with only 4 moving parts. Super reliable. Built like tanks.
♦ They are _quiet_ in operation.
♦ The Extreme modulates the burner to a very low kW rating. This avoids/vastly reduces inefficient boiler cycling.
♦ Have an outside weather compensator sensor fitted - £25-£30. Intergas come with weather compensation as standard.
♦ Have an _Opentherm_ stat on the wall.
♦ Opentherm stat and outside sensors keep the burner as low as possible _modulating_ the burner down as much as possible - the Extreme burner modulates very low. If the house only need an input of say 3 kw, the burner just ticks over slowly and silently. No inefficeint on-off.
♦ Uprate the gas pipe to 22mm all the way. Find out where the 22mm of the gas pipe ends, there may not be a lot of 15mm pipe there, as the existing boiler is quite a high gas rate. If the cooker pipe is on a separate pipe direct from the meter and is adjacent, this can be teed into the 15mm gas pipe at the boiler creating a gas ring, similar to an electric ring, which may prevent problems in getting a larger bore pipe to the boiler.
♦ The intergas can still be open vented, in keeping the small F&E tank in the loft. The only combis that can be open vented. I would make it a sealed system - unless the rads are very old. High pressures may pop them, then more needless expense. If old, it may be worth keeping the F&E tank until new rads are fitted then get rid of it making it sealed (pressurised).
♦ Replace main water stop tap with a full bore tap to improve water flowrate.
♦ Take combi hot draw off pipe up to cylinder position connecting onto hot pipe there.
♦ Tee onto hot pipe in room where combi is, so hot water does not come from upstairs to downstairs.
♦ As Allen says, connect cold main in loft to old cold feed from tank in loft.
♦ Fit a magnetic/solids filter.
♦ Fit scale reducer.
See my post. Could also fit the Intergas smart phone control system, if that floats your boat.
Based on what I gleened from the vid.
♦ You will not look back.
I would fit either the Intergas or a Navien as second choice. The Navien gets the outside temperature for the control system off the cell phone network so no wiring or outside sensor to be fitted. A touch screen control panel. Navien are the biggest combi makers in the world. Quality product.
I found that the house has a bathroom and an ensuite. I assume only a shower in the ensuite. If it was mine. A Viessmann 111 stored water combi as 1st choice. A quality product that will deliver the hot water providing the mains flow and pressure is adequate and the pipework is sized and designed properly (Have a _dedicated_ 22mm pipe from the stopcock to the combi). Saves space by removing tank and cylinder. Can have heat in the airing cupboard by having a small rad in there on the back wall.
Alternative:
♦ An Intergas Rapid 32kW combi (well priced) connected to the *showers* and hot sink tap in kitchen, to give high pressure showers and instant hot water at the kitchen tap.
♦ Try to have Handsgrohe Raindance type of shower heads (aerated) at they consume far less water.
♦ To fill the bath and serve the rest of the hot water, a low pressure combination cylinder (cold tank incorporated). like this:
www.tradeplumbing.co.uk/gle...ffz_Dp2is5Px0Bqxmbst9EaAl1zEALw_wcB&sel=47082
♦ Cylinder can provide hot water to the bath and all other hot outlets. This will be heated by the combi as a system boiler would do. ( a combi is a system boiler with a water section).
♦ Combination cylinder can be in the existing cylinder's location, or in the loft - providing it can get up there and it is supported well enough.
♦ Having a vented combination cylinder means no expensive pressure valves, annual service, explosion risk, expensive G3 approved plumbers only to work on it, as on unvented cylinders.
♦ I would have the Intergas Rapid on a vented loft F&E tank as pressurising the rad circuit may bust a few old rads giving more expense. When rads are replaced pressurise the system removing the F&E tank.
♦ So, the cylinder can be off, except when you want baths or hot water at the bathroom basin taps (very rare). Then lower running costs, as you are not heating hot water unnecessarily.
@@johnburns4017 Hi John, thanks for your additional reply much appreciated. I've been a bit busy with work, so only just collating everyone's views and recommendations. I agree with your thoughts and points of caution, there is quite a lot to take into account. I will let everyone know what I choose as soon as I can via Allen. The biggest pain is going to be the gas pipe, there is a possible route through, but its the living room floor up and then chopping out in the under stairs screed to get the pipe through! Thanks again for your valuable input, Cheers, Dave.
Hi Alan if flow and pressure on the mains is up to scratch, I'd be going 35kw combi, upgrade the gas I tend to go 28mm to within a couple of metres of the boiler if possible.
Decent manufacturer flush the system well, allow for an electrolytic or magnetic descaler on the mains, a good central heating filter and always fit a shock arrestor as standard.
Another good video mate you're like the Steven Spielberg of the plumbing and heating industry ha ha 👍
Thank you so much for taking your time to comment.
35kw? What's the justification for such a large boiler?
Sorry Richard should of explained myself better, what will do a lot will do a little, obviously I wouldn't fit a 35kw in a flat or terraced property, but looking at the gentleman's video he said he'd also got an en suite besides his bathroom and kitchen so potential for three hot water draw offs simultaneously.
The heating not a problem, most manufacturers you can adjust that load through the settings menu.
It was purely through my experience and knowledge I suggested the 35kw option and just my own opinion, I've been to plenty of 24kw combis in 4 bedroom, 2 bathroom and ensuite properties and well say no more
Hi Mark, thanks for your input. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I haven't considered a shock arrestor, so will put that on my list of items. The water pressure here is quite good with a good flow, but I haven't had it measured so can't give you a figure.
@@DaveC3350 Hi Dave I'm guessing you know a decent plumber/gas engineer in your neck of the woods to test the pressure, it's just a guage you screw on to a 3/4 bsp thread either outside tap or washing machine tap will be fine, if it's over 7bar it will need a pressure reducing valve but it's very rare the water mains will be over that👍
Cant brush my teeth in there... Here is me who has brushed with water from the loft tank for 33 years...
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Never consider a Combi boiler if you have the option, why? The amount of fresh water you will waste whilst waiting for hot water to come through (not to mention frustration) might be acceptable in some parts, but having lived in areas of the country often suffering a water shortage you can bet you right arm water costs will rise in future.
Im not registered plumber, just engineer, but for my former farmhouse i designed and installed unvented system with large water cylinder. Always had virtually instant hot water in 3 bathrooms, including showers. Sold property 6 years later, never had single problem during interim.
Hi, thanks for your reply. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution. I agree I should consider water wastage, as I've not had any real hands on experience of a combi, so it would be good to get an idea of how many litres need to pass through the boiler before the output reaches temperature?
Can I still use my old dial thermostat for a new combi?
Hi alan.. Have you removed the xtra long video.. As can't find it.. And will you be doing another video on the 2 boilers..
Thanks
Yes and Yes. I did a live video to ask for feedback or input into the next video but it ended up been over 2 hours long 😂No body wants to watch me for 2 hours
I would say you have to install a combi boiler
Think a Baxi 836 fitted in place of existing with up grade to gas supply or maybe fitted in cylinder cupboard upstairs .Only small family so why go to extreme expense or unvented or even keep open vented cylinder for small hot water requirement
Definitely not a Worcester combi tho
Richard Williams been in trade now for 55 years
Hi Richard, thanks for your reply. I've been a bit busy with work, so only just collating everyone's views and recommendations. I agree with your thoughts, and will let everyone know the outcome as soon as I can. Cheers, Dave.
Combi and existing hw tank, use the combi to feed the shower in the ensuite and the existing tank for the bath. If they don't mind juggling by filling Bath first and then someone using shower once full then straight combi. And replace bath and shower valves with thermostatic ones.
Hi, thanks for your comment. I'm going to give it a week or so and then review all comments and way up the pros and cons of each solution.
BTW the HW relay works the opposite way around on a intergas so on /closed contact is off.
Also I have a tank stat and room stat to override the Internet ones just in case they loose connection.
Hi Allen, what's your thoughts on electric combi boilers?
Only the rich can afford to run one
great video
Just had an Intergas boiler fitted only 4 moving parts, no plastic bits. Economical and quiet don't waste your time on anything else.
Why do you think a boiler with less parts is better?
@@AllenHart999 less moving parts less to go wrong, diverter valves, no separate DHW heater, no plastic parts in contact with water.
Combi nothing but trouble, fit like for like with a cold water mains feed to the bathroom sink tap/ toilet along with a thermostatic mixer valve for the hot side of the sink.
Storage boilers will save space In airing cupboard
Vailent, 937 storage boilers
But I would get rid of Boilers so much wasted heat sol air pannel heaters in each room
Boiler hut website
Someone said if you remove water from loft it reduces home insurance
Definitely change to 22mm no matter what and go for a Baxi..
If he has low water pressure and wants to install a pump for the shower, you cant have a combi, no?
You're the best
wouldn't dismiss the worcester, most breakdowns are caused by bad installation.
👍👍👍
Easy , combi due to low hot water demand , logic max
Ideal are also in Hull, Thanks for the comments.
Throw a bit more on because there's no way you're getting any scrap
Never a combi boiler for me system boiler and megaflow if u have the water flow. Mains water everywhere no pumps and if u have a problem with your boiler u can turn immersion on for hot water.
Megaflo? Are you serious? The one with the internal air bubble that dissolves and the internal plastic baffle disintegrates? Made by Satan himself.
Then all the unvented pressure reducing and protection valves, that when they fail cost and arm and a leg to replace. That also need an annual service with only G3 approved men to work on them? Give them a wide berth. Fit one of these (low pressure) with a combi heating it with _only_ the high pressure shower off the combi. It does exactly the same as an unvented cylinder, not costing a fortune to run. And will not explode.
www.tradeplumbing.co.uk/gle...ffz_Dp2is5Px0Bqxmbst9EaAl1zEALw_wcB&sel=47082
Hi Alan my god this gentleman has confused me what's the story here first of all how many bedrooms bathrooms and and for a start no combination for a house only for flats and then take it from there confusing video long story I think there is a catch to this the way he's talking he knows a bit about this thank you
Hi, thanks for your comment. The video was originally intended just for Allen, but he thought by sharing it it would help me with my decision / system choice. The property is a detached house, 4 bedrooms, one bathroom, one en-suite, living room-dining room and a kitchen. I'm an electrician by trade, and wired up many systems and also done quite a lot of plumbing in the past 40 years for myself, so I am familiar with the various system choices, just struggling to decide what is best.
@@DaveC3350
How many showers? how many baths? Hard water area? *Important.*
Combis are only for flats? You really should get up to speed at what is on the market these days.
@@johnburns4017 Hi John, 1 shower in en-suite, 1 bath with show mixer (only used to rinse down), other than that typical 4 bed house. We are in a hard water area, so I will add a scale reducer to my list. Thanks again for your input. Cheers, Dave.
Eney boiler fitters nr Chester on here sorry to ask Alan
No problem. Merry Christmas
I will be a plumber soon but not Yet I'm at college
Good luck with it all. If you need any help let me know. Thanks.
Combi boiler are very finicy. No really competent engeneers in uk who can maintain it either. The good old oil radiators on electricity is way better and cheaper
Hate combi boilers. System boiler and unvented cylinder for me
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@@AllenHart999 already subscribed for ages!
@@idmax Thank You