Why NOT to use Buffers or LOW LOSS HEADERS! The Low Loss header explained.
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- Опубліковано 19 гру 2024
- Domestic heating seems to be finally coming out of the bronze age. With it however, and in a healthy contest to give the customers the best solution possible, we can fall foul to products being sold to us we just don't need. Here's some thoughts on why a low loss header is not going to improve your job if you don't need one, probably...
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in my opinion, the correct answer to whether we should use a buffer tank in an installation is that it depends. The buffer tank offered us several advantages (however, it also has some disadvantages such as increased installation cost, the requirement for additional installation space, and installation complexity) All heat pumps have a minimum volume of water required for their smooth operation (take into account, for example, an installation with a fan coil units where the volume of water they take is smaller compared to the radiator heat radiator). This volume, depending on the model and size of the heat pump, ranges from 60~160lt (mass flow rate, correct pipe size, correct dimensioning of heating radiator, 55C in the inlet, ΔT 5). If I have this volume in the system, it is not deemed necessary to place a buffer tank, neither in the supply nor in the return. If we consider that the pump works 24 hours a day, we will understand that the inertness offered by a buffer tank is important. let's include in the positives that in snowy conditions it will prevent the many defrosting functions of the pump (less operating cost)
Thank you Heat Geek for sharing your knowledge.
I think I found the holy grail for my heat pump system by adding a buffer on the return only.
This allows you to run radiators and underfloor etc. without loosing efficiency.
I achieved a delta t 4C advantage on my heat pump.
You sir are amazing giving so much information, we almost install boilers etc with our eyes closed.
Thanks Ranjit! Merry Xmas!
absolutely brilliant, never seen so much value on a UA-cam heating video...
Cheers Shaun
There are quite a few errors in the thinking here. Has nobody else spotted them ? C'mon guys, I can't be the only one.
@@claudiahamminger-stone3274 stop trolling, and spill the beans. as far as I'm concerned, it all made sense
Great video. I’ve just left the heating industry to move into electrical/mechanical but still love my old trade, videos like yours really keep me in touch and your videos are even more in-depth. So thank you.
No problem! Thanks for commenting
Thanks!
I love your videos but that music in the background is really distracting!
Well, I’ve just watched it again two years later and I didn’t find it distracting so I must’ve been a bit grumpier back then!😂
Lots of charm in the older, less polished videos!
Definitely irritating! I mean what IS the point of it?
Love that! Quick and simplified! I’m a 63 year old enlightened heating engineer now😊👍
Hi Adam, thanks for this video explaining the disadvantage of buffer tank. I'm using a LG Therma V Monobloc 9kw heatpump and manufacturer is suggesting installing a buffer tank of minimum 50lt and a circulation pump (controlled by a third party thermostat) to circulate the secondary system water to radiators. Why would LG suggest this if it's causing efficiency losses?
Is it wrong to get so excited about latent heat?!? One of the great blessings of the earth! Great video! Thanks for your work!
It's perfectly natural
Brilliant, I especially found the last part informative. I also call myself a bit of a geek, I kinda feel like you are in this video, when I'm explaining to customers why their PRV is dripping coz their Engineer hasn't even looked at the Expansion vessel for the last 5 years. I often get my pens out to explain. Not a fan of the usual way of just saying its buggered! subscribed!
I’ve just released a course detailing everything you need to know to become a heating genius! What’s more it’s been recognised by the UK government department BEIS which have offered to heavily subsidised the first 300 spaces!
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We do low temp gas systems designed @ 50 -3 and they work amazing, keep the videos coming mate
Much more to come..
Thankyou thar was a great video. Please do all the others that you were tslking about as well. Your Knowledge of it all is absolutely amazing!
Thanks Matthew really kind!
Yes UFH piped directly to a large combi makes it all so much simpler. Best to have a boiler that modulates very low to eliminate or vastly reduce boiler cycling.
Geminox had a boiler that modulated down to 1kW to a max of 12kW. It was so unreliable though. I think it has now been discontinued.
I once fitted a low modulating system boiler directly onto UFH, that is all it did. For DHW, a Rinnai multi-point was fitted *externally* on the outside wall - yes they can be, as can Navien boilers these days. Worked like a dream. Cost effective to install. Rinnais can really throw out the DHW flow rates.
No cylinder or complex zone valves, etc. Saved a ton of internal space.
American's wouldn't think twice about installing one gas heater for the hot water and another for space heating...
@@edc1569
We do not have teh space they have, as we have rabbit hutch houses, in a country with only 7.7% of the land settled.
Appreciate taking the time to explain it 👌
Mr Heat Geek ..... Best presentation ever on LLH. I have a stupid question that I couldn't find an cogent answer in spite of searching the web for a week. I think my questions relates to people who upgrade from cast iron boilers to hi-efficiency boilers. I have a 1980s 4700 sf house with finned baseboards. Baseboards are too expensive to replace, so in spite of needing more, it is uneconomical to replace them. Having a modulating boiler with low water temps, and near constant flow seems like a good way to maintain a comfortable temperature. There are 2 zones upstairs, 6 zones in main floor living area, and 1 zone in basement. The main floor is ½ heated with in floor heating. It faces the south, and so heats up much faster than the rest of that floor, and it stays warm longer because it has tile floor with larger thermal mass.. Hence the zones. I am replacing my 40 year old cast iron boiler with a high efficiency Lochinvar KHB110. My contractor tells me it will costs $22,000 for the upgrade which includes all valves, pumps, etc. he wont just replace the boiler. I replaced all the ball valves and zone valves a couple of years ago, so I know they are good. So I am planning to DIY and keep as much of the existing valves/plumbing as possible. Parts and materials will be less than $7000. I have have to spend another $2000 to get a friend to do the actual work. The questions is: why do I want or need a primary/secondary loop? I thought the biggest reasons for P/S were to 1) reduce the temp of the inlet water (shock to the heat exchanger), and also create a path for the boiler circulator. Well, if I ran the system temp as low as possible (based on the fact that I have 40 year old baseboards tha are not something I will replace), why do I need to reduce thermal shock? Ultimately the goal is to have boiler/system pump should run 4 hours or more without start/stop. Also, Low outlet temps = low Delta T. So no worries of thermal shock to the heat exchanger. Also , If I turn OFF the included boiler pump, and have a variable system circulator that runs only if there is demand from the thermostat, why do I NEED a primary loop? Balancing the primary/secondary for all system demands with 8 zones would be virtually impossible with a low loss header. Even if I were to power multiple zones on my main floor from a single thermostat to increase heat dissipation, the system circulator would either be overpower or under powering the boiler circulator based on heat demands (single or multiple zones demanding heat). As long as the goal of a homeowner is to provide fuel efficiency over matching instant heat supply to demand, it seems the P/S loop doesn't make sense. Or am I missing something?
Low loss headers serve greatest benefit in cascaded boiler setups, in these situations, each boiler has its own pump that could well be inverter driven to optimise heat transfer through the heat exchanger. Cascades will have different sequencing to balance load and wear on the cascade. It may also be the case that consideration might have been given to seasonal demands of the installation, winter and summer are only 3months losing each, as are spring and autumn, the result is that in summer only the water may need heating (3-10kw coil) a couple of hours a day. In autumn and spring larger energy source may be required, for spells in the depth of winter even more. Running a large boiler may not prove economical, running 3 or more boilers of different sizes extends both the life of and the performance of the system as a whole. Low loss headers stabilise boiler water flow, like buffer vessels - properly sized, prevent boiler short cycling which wastes gas, or on the case of heat pumps electricity and compressor start stop wear.
Excellent presentation and very thought provoking.
Are you going to explain buffer tanks ?.
Vailant said that I can install there low loss header up to a distant of 5 meters away from boiler. This will solve a installation place for fitting. I see diagrams where there is nothing connected in-between the header and the boiler for circulation purposes, then everything is connected from the header to different zones. My question is I want to keep zone 1 ch/dhw, ground level circulating . Upper floor zone 2 and loft area and additional circulation pump connected to LLH. Will flow and return. From zone 1 interfere with zone 2 and keep separation when both zones are operating and calling for heat. Flow rate from boiler is 17.1 Lpm . 25/80 pump flow rate of up to 5.7M3/h, your views will be much appreciated
Just discovered this channel. Amazing content. Thank you
I’ve just released a course detailing everything you need to know to become a heating genius! What’s more it’s been recognised by the UK government department BEIS which have offered to heavily subsidised the first 300 spaces!
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Excellent video, whether on viessmann vitodens 050 the pump modulates without weather control sensor.? Pump inside is upm3 15-75
Good technical video.
I do a fair bit of double boiler LLH work in big houses in N London.
Max you can get out of boilers these days is 70°C.
Sometimes it's not enough especially in winter.
Good to know where to take off for UFH.
Got to install UFH in future job.
Top vid 👍
Adam, so obvious now you pointed it out, great video by the way.
Glad you followed it greg. It's hard to explain in person but taking the time to do a vid makes you hopefully put it in a more clear way.
Now you are getting to the nite gritty, wonderful stuff 😀
Thanks pal, very easily digestible information there, subscribed 👍
Thanks bud appreciated 👍
I’ve got an existing system with a 500l thermal store heated by a wood burning boiler and a gas boiler.
I’m replacing the gas boiler with a heat pump. I would like to retain the thermal store as a giant buffer to store off peak heat from the heat pump - and to retain the wood burning boiler.
Most heat pumps are not set up for high low temps when electricity is 4x cheaper.
This is getting complex before solar and batteries are added…
(Hot water will be a new separate cylinder preheated by the thermal store…)
Suggestions
What about if you have an ASHP with a required flow rate of 9L/m (Vaillant Areotherm) and the flow rate in a house heated by 100% UFH and the total flow rate of the UFH is 10,34 L/m?
great video nicely explained. be really good to see those other videos you mentioned in this
Thanks bud
Very helpful to a trainee such as myself, keep em coming. Thanks
I’ve just released a course detailing everything you need to know to become a heating genius! What’s more it’s been recognised by the UK government department BEIS which have offered to heavily subsidised the first 300 spaces!
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Great video, I been a heating engineer for 15 years but it rarely come across low loss headers, but a customer of mind has ask me to look at a system put in there new build house. The have a low loss header running 2 big underfloor systems one towel rail/rad Circuit and unvented cylinder
When it’s very cold outside the hot water stops work and the pipe to it is Luke warm. It is the bottom take off on a 4 taken off vertical header, if you shut off the other circuit it heat. It have 2 30kw boilers connected to it.
Any help would be great Thanks
The ufh is taking all the flow. This is a common problem with llh with multiple take offs
Thank you . This is awesome. Would love a more detail on the CCT near the manifold . Mentioned about 12.17 .
I’ve just released a course detailing everything you need to know to become a heating genius! What’s more it’s been recognised by the UK government department BEIS which have offered to heavily subsidised the first 300 spaces!
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Is it more advantageous to include a buffer tank in a scenario where only underfloor heating is used with a heat pump? The power output of the heat pump is specifically matched to the requirements of the underfloor heating system (so it's not 1/3 or 1/2 od the heatpump power output).
install Low Loss Header, but because of lack of space to install LLH vertical, what distance from the boiler can I position the LLH, the boiler would operate normally ground floor, install LLH on second floor use 15/60 pump instead of 25/80 pump to circulate flow to second floor and loft area
Explained so bloody well love it.
My dilemma is how to get enough flow to the loft area in an old Victorian house. (12ft high ceilings) An 8m pump will do the trick as the boiler 42kw cdi 2 zone S. plan, was positioned incorrectly for the 15/60 pump to deliver enough flow to heat the radiators on a part of second floor and loft. (1) If I can get a 8m pump head only replacement to fit the boiler casing. (would this work on the boiler as it is only affecting flow) (2) reposition boiler higher to compensate for poor flow rate. (3) install Low Loss Header, but because of lack of space to install LLH vertical, what distance from the boiler can I position the LLH, the boiler would operate normally ground floor, install LLH on second floor use 15/60 pump instead of 25/80 pump to circulate flow to second floor and loft area. I have seen LLH fitted horizontally yet you say not advisable. Use a Blanking plate on boiler pump then install an external 25/80 pump, without the need for a LLH . your thoughts would be helpful thanks
An 8m head pump does not mean it circulates 8m high. This is a common misconception
Are you not just adding a full bore 22mm bypass by using a close coupled tee before a manifold?
Hi Joe. Great point! This would ideally have some sort of balancing valve on the feed to the CCT and epending on the control type you may also require a 2 port aswell. However this is a whole subject in its self. There is no one answer for all the different system types and so we are doing a video on this very subject (hydraulic seperation for manifolds) very soon!
Yes !
Great video really well explained looking forward to more 👍
So much more to give!!! Thanks! Spread the word!
I’ve just released a course detailing everything you need to know to become a heating genius! What’s more it’s been recognised by the UK government department BEIS which have offered to heavily subsidised the first 300 spaces!
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What goes 'into a tee" , comes 'out of a tee', right?.
I read a couple of interesting books by Dan Holohan a few years ago. Great video by the way 👍
What about buffer tanks? Do I need one?
Is it the same as these low loss headers explained here?
Hi Adam, I notice you seem to have solar water heating arrays on the side of your office building, similar to the evacuated tube type? What is your opinion of the so called Bunsen Water heaters which are similarly mounted black panels, but which use a refrigerant to transfer the heat to a heat pump, and then the water cylinder? Nick
Really interesting stuff. Thanks!
Great video, thank you!
Absolutely brilliant. Keep them coming.
Thanks Jess! What else would you like to see?
Thanks . Really informative. Love CCTs. Be interesting to see your vid on this .
Thanks for commenting 😄
Great explanation, I've never met a plumber who would begin to do the calcs you have shown on a domestic prop. I wouldn't feel anyone would set the pumps correctly without knowing some of this info. I've just been recommended to put in a low loss header on a brand new 5 bed house with new install, new 35kw system boiler with tank and NO underfloor heating. Also suggesting a second pump. Am I right in thinking that a boiler will have a pump rated for its output so will "generally" be good enough for the job without the extras.
Genrally good enough ino matey!!
Check out our course btw!
Courses.heatgeek.com
On domestic it is all wet finger in the air. Some awful inefficient systems out there.
Excellent info. Very helpful.
Thanks bud
I’ve had a LLH installed as part of my HT Daikin ASHP, without a doubt none of these calculations were done by my installer. I was told I just needed one as I have a zone for upstairs and a zone for downstairs heaters, is this incorrect?
Not necessarily, it depends what each zone flow rate is. If they both can be at the same flow rate then it's pointless having separation.
Excellent video, keep content coming mate 👍
Thanks Jamie.. Loads on our website too! www.heatgeek.com.. boring text and images though im afraid
I’ve just released a course detailing everything you need to know to become a heating genius! What’s more it’s been recognised by the UK government department BEIS which have offered to heavily subsidised the first 300 spaces!
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Question: if you put the CCT in front of the UHF, boiler pump will run only through the CCT and water won't flow through the radiators due to resistance?
Wicked video brv....subbed
Fantastic, please continue with these. Would like to know what degree/ courses you gained this knowledge.
Thanks! Its litrally just from debate on the internet for hours.. I have a passion for finding out the truth..
I’ve just released a course detailing everything you need to know to become a heating genius! What’s more it’s been recognised by the UK government department BEIS which have offered to heavily subsidised the first 300 spaces!
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Well done Adam I like the style long time coming!
Thanks Bret 👍
What about primary-secondary loops with closely spaced tees? You do need two pumps or more, but the pumps don't ever fight one another.
You get the same mixing. Not good
Hello Adam, I’m really enjoying your videos.👍
Just a thought, do you undertake site visits.
I work in a large university which incorporates 40+ plant rooms and as far as I’m concerned nothing has been done correctly.
Kind regards,
Les.
What would you recommend for a 4 storey house with 23 radiators and 1 hot water cylinder? Each floor would have its own heating circuit. I am thinking of using a 48kw boiler and the IMI Zeparo Low Loss Header and fit 5 Grundfos circulator pumps for each circuit. Do you think there would be distortion and low heat distribution towards the heating circuits during high demand?
The first thing i would reccomend is doing a proper heat loss survey... how did you arrive at 48kw? That sounds very high. What's the m2 floor space?
5 pumps for each circuit is also a little over the top. 1 each max.
And yes there will always be distortion with any hydraulic seperation.
@@HeatGeek Thanks for the quick reply. Yes I meant 1 pump on each of the circuits. 5 pumps in total.
This is a very large house with massive rooms and high ceilings. 4.5 bathrooms, 5 bedrooms, 2 living rooms, very large kitchen and dining area, gym room, 2 more rooms in the basement and garage too. There are 23 big radiators each needing about 3.5k - 4k in BTUs. 300l unvented cylinder. The old boiler there was 37kw and it only heated up half of the house, the rest was cold. So I am thinking of using the 48kw and if need be I can rate the kW output down a bit to suit the system. And the reason for the Low Loss Header is to increase the flowrates to each floor and make sure all rads get hot.
@@veniamindoychev1634 what you are saying will work. Over specking any system will always work however wont be as efficient. It sounds like the low loss header might be used for additional pump head, but using it to increase flow rates is not a great idea as your delta t will shrink and lessen the condensing effect.
Regarding the size of the rooms etc and description, this isnt really how heat loss is done. The main variable is insulation. Yes you can select an oversized boiler and range rate it down but you also then reduce your modulation ratio. If you can give me the age of the building and m2 floor space I will give you an idea of what I think the heat loss is of you like?
@@HeatGeek
I will calculate it all and get back to you. Cheers for the solid advice!
@@veniamindoychev1634 no problem bud!
Great video, thanks 👍
Thank you
Really helpful explanation. ***
Im interested in two boilers installed in series in a large domestic house
Series is not a suggested installation method. It gives uneven wear and tear.
Really interesting and made a lot more easier to grasp! P.s where do you learn this info ?
Thanks Mark imand I'm glad mate. Alot of debate and reading..
I’ve just released a course detailing everything you need to know to become a heating genius! What’s more it’s been recognised by the UK government department BEIS which have offered to heavily subsidised the first 300 spaces!
courses.heatgeek.com/
Hi, is it possible to use a splitter with two heating circuits and two pumps, or is it also a problem for normal operation? Thanks
fantastic video mate!! please keep them going really enjoy this stuff!!
Thanks Stephen
Great video. Subscribed. Thanks
Thanks tom!
Blimey mate. I've been an installer for 35 years with a reputation for good technical ability I'm way ,way behind you, I shall be checking out your vids to get my skills back up to speed,thanks and what is your background if you dont mind?
Hi Roland. Thanks much appreciated!! 😁Just a normal apprenticeship and too much time on forums!! Check our our course!! Courses.heatgeek.com
I use a Nibe UKV 100 as a low loss header ;)
Great video!
Quick question: new installation was suggested with modern wall gas condensing unit with automatic modulation and inverter. System has 3 zones which are made with a kit that consists of a hydraulic separator with 3 circulators. All zones are with radiators and all in one floor/apartment.
This way don’t we lose all the smart features of the unit?
Isn’t it more efficient - if the unit’s circulator is sufficient for the system flow - to install a manifold with 3 gate valves and create the zones?
Thanks, looking forward to your response!
Your absolutely correct.. they're installing crap they don't need to and reducing efficiency in thr process.. engineers love doing this in the US.. all about power and not about efficiency..
@@HeatGeek same thing here.. overcomplicating everything..
do you have a video about calculating head and flow rate in a two pipe system with collector manifolds (each radiator has its own 2 dedicated lines)? I saw somewhere that as a rule of thumb the calculation is Q=Kw/dt in m3/h at 2-3m head for a two pipe system.
@@Speedmaster5445 not yet
Does it matter if a pump is on the flow or return?
That depends on a few other things.. you should always pump away from the neutral point and thr llh is usually neutral.. however you want to keep a pump cool.. so return of you can put an expansion vessel behind it .. theres other complexities too
Really good stuff.👍
Great stuff.
Out of curiosity, where did you go to get these pearls of wisdom ?
Andrew riley hours of debate on the internet and facebook 😂 distortion is my theory though.. you wont find much in text books about it.. caleffi talk about 'blending and mixing' but dont seem to see the issue with it for condensing boilers which there absolutely is. I think this is because they arent driven by efficiency in America but more 'power'.
The ironic thing is that it may give more pump power. But not more heating power as the boiler is more likely to max out and modulate down.
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Can the cylinder flow and return be fitted before the header when its a system boiler ?
I have a radiator system fed by a microbore network supplied by a heat pump. I have a small vertical low loss header installed, to which the primary circuit is connected to both supply and return ports, as normal. However, on the other side of the LLH, only the supply (top) outlet port to the secondary circuit is connected, the secondary return (bottom) port being sealed off. Instead the secondary return is connected directly to the primary circuit at some point further back downstream towards the heat pump, so bypassing the LLH altogether. On the face of it this seems like a good solution as it gives some hydraulic separation but avoids any mixing of the supply and return flows within the LLH. What is your view?
I thinks that's a fool's game.
In the case of a buffer tank in parellel, depending on the flow rate, the mixing can be more of an issue even in the case of closely matching primary and secondary flow rates, but there are solutions (with various succes rate) for that, one is similar to your setup, but preferably adding a T before the primary input to the buffer. 3-pipe setup in some nomenclature.
HOWEVER:
If the primary and the secondary flow rates match, there shouldn't be much mixing in a proper LLH.
If the flow rates have mismatch between the two side, that T it won't do any good. For example: the secondary doing higher rate, it will have to suck back from that described tee to the LLH (the differential volume has to come from somewhere), and it will mix in the LLH anyway.
If the primary is doing higher rates (the worse scenario) then the mixing will happen at that where the secondary joins the differental rate of the primary coming from the LLH.
So you have no gains either the rates differ or don't.
But you have disadvantages both cases: you get more pressure loss than if it were a simple LLH: you can imagine the flow hitting the your small T's upper wall, and part of it going left, part of it going right. The LLH is a better desinged vessel, actually, it is designed for this specific job: only the differential rate should be going up or down.
And you have more straight tubing distance, but if the T is not meters away, then it adds less pressure loss.
Either the installer was a fool IMO, or the LLH port had some issue, but they didn't want to buy another one...
@@KrisztiánSzegi thanks for the info. My house is 2 storey, 130sqm floor area. there are 16 oversize radiators fed by 8mm copper microbore. The small (c. 2 litre) LLH is in 3 port config, separating the primary and secondary circuits. The primary pump is a Grundfoss UPS2 25-80 180 on speed 2. The secondary pump is a Grundfoss UPS3 15/50-65 130 on speed 2. What is your view of the effectiveness of this setup?
@@lumbarsupport First of all, I am NOT a heating engineer.
I learnt chemical engineering, and part of the course is chemical operations, with jacket and coil heated tank chemical reactors, fluid dynamics, etc.
I'd say I understand heating as well as a good heating technician when I want to, and as I am planning the heating of our family house currently, I very much DO want to understand it :)
I wouldn't be too much worried about your LLH, although my wording maybe did imply otherwise. It's just that I don't, of more precisely, I fail to see ANY benefit. The circulation losses could be lower than with that separate T junction, but that would be equal to a few meters of additional pipe length of pressure loss.
Regarding your described setup: as long as the flow speed is around 0.3-1 m/s (given by: dividing the flow rate by pipe inner diameter), it would be right, the lower, less the pipe wall erosion, noise, and friction losses are.
I would need more data (the available head of heat pump's circulation pump, all of your pipework layout (with number of elbows, height difference of lowest/highest point), the assumed/required flow rate to meet the heating losses) to say that it would have been possible without that LLH: doing the heat pump all the circulation work. I'd say, maybe.
Zoning and regulation between the the floors is a topic in itself, and that could be a good point to optimize without changing much of your setup, given you already have separation between the primary and secondary.
But I am not versed in the latter part, as our house will have UFH (just got the screed a month ago) on a single floor, and at first, it won't have any zoning.
Great explanation but I need more time in the class room 😂👍
The more you watch it.. the more you'll understand 👍
Are you familiar with Dunsley neutralizer? Same principal?
@@davidkneale7455 You are better off using a thermal store.
As always , quality video
Great video Sir. I am wondering if you may give me an advise for my UFH system, since l am really appreciate your knowledge.
I am having a biomass boiler of 15kw for 100m2 UFH. Boiler is having an integrated pump Willo Star RS25/6. Last winter was the first season for us to use it. What I have noticed is that l am not having good flow of hot water in the farthest room form manifold. Floor never gets hot enough, just in case if boiler is working in full capacity (5.speed which is 15kw).
I would like to ask, according to your experience and knowledge, do l need to add one more pump in order to increase flow rate?
Thank you.
Hi. Have you balanced the system? Will the room get got if you turn off the other zones?
@@HeatGeek Well l am having manifold with no flow meters, so l tried to balance but it's hard if you don't actually have a measurement, so l keep all vents fully opened. It's in plan to change it for the one with flow meters. YES it's getting warmer when l close other zones and flow is much better. Thank you for your answer.
@@vladimirradenkovic4413 Your pump head must be good enough if the furthest loop heats so you just need to balance. You don't need flow meters though!.. a much more accurate way is to balance for the same temperature drop across each loop.
@@HeatGeek l am not sure how to do it that way according to temperature drop. Sorry, maybe it's a language barrier since English is not my native language.
How to deal with multiple heating zones with mixer that have there own schedule and flow temps?
Use zone valves instead.
One important aspect of UFH you did not touch on, and is the most important, would be the floor surface temperature when it is being heated, and is the UFH being done through a 10cm slab. Also, is the boiler a condensing boiler or not. If it is not meant to condense than you are dealing with sulfur condensation on the inside of the boiler that will rot the boiler in a few years. I don't believe you should mix UFH in lesson with standard baseboard or cast heating. It tends to cause more problems than solutions.
Non condensing boilers were banned 16 years ago in the UK so safe to assume a condensing i would say for new installs which this is for. Lots of extra things I could have put in here but if I dont cut stuff out i could go in forever!!
@@HeatGeek it was a brilliant video. I am in Canada, and the east coast still uses oil boilers, which the majority is still condensing. Your video has crossed the pond, and I just wanted to remind you that you are global. Keep up the great videos.
Having had a discussion today with my heating engineer he has suggested installing a LLH as part of the system expansion. All the reasons he gave seemed to be valid and he had convinced me it was worth paying for... until I watched your video, now I am utterly confused. LLH or No LLH? That is the question. The current system consists of a 10 year old Vaillant ecotec plus 637 system boiler and 260 litre unvented uniSTOR cylinder. The house is 5 bed, 3 bath over 3 floors and there are 12 radiators (mainly medium in size) and 3 large towel rails. 5 years ago, the system was expanded to include a UFH zone for a large dining/sitting/kitchen area extension. The system now has 3 zones; CH over 3 floors, UFH (3 port manifold has its own pump) and DHW. Last year I had flow issues with the 3 loft radiators and had to flush the pipes to clean out the silt, which resolved the issue. I'm in the process of having bathroom UFH installed with a 1 port manifold including pump and the heating engineer has recommended installing a Spirotech LLH, an additional pump (on the system side of the LLH), a new 22mm supply/return to the new bathroom UFH. Part of the reason for introducing the LLH was due to the 2 UFH zones and large CH zone which may now struggle to be supplied by the boiler pump. A new Vaillant VR 71 wiring centre (4 zones) + controls will also be installed. Is this the type of system you think will benefit from a LLH due to the differing heat requirements of the CH & UFH or do you think this system would suffer if a LLH was installed?
Hello bud. It is almost certainly the type of system you would put a llh on. However of your not getting issues now then I fail to see what issues 1 small bathroom will add? Can you bot explain to the customer that you would try the simple option and if flow issues are experienced you can upgrade to a llh for an extra x£?
Most customer will appreciate the honesty and the fact your are trying to save money
Brilliant video 👍
Thanks Dale
Excellent video, very helpful and informative! I can continue to pretend that I actually know what I am talking about at work 😉😂
😂😂😂 do the right thing and share 😉
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Great video thanks....I'm not sure I've got why the 1/3 rule. Is it experience? I'm in a close situation (26 kW boiler and 10 kW flat) and cannot set the design flow rates for the UFH. Still the delta T is getting to 7C and even lower...do I need anyway to install an additional pump + LLH in your opinion? Confused....
Isn't the primary and secondary balancing not really a problem if using fixed speed pumps?
No because the primary pumps aren't fixed speed. Also.. you haven't been able to buy fixed speed pumps in the uk for years.
@HeatGeek Hi thanks for the reply. I'm confused. Im sure my heat pump has a selectable 3 speed pump and my boiler pump is a Grundfos 15-60-130 , again 3 speed selectable?
I'm building a bivalent system with LLH and hoping to balance primary and secondary using those 3 speed pumps . Both sides will be running on a dT10.
@Matt Cole erp pumps use foxed pressure or proportional pressure. Not speed. They vary the speed to obtain the selected pressure and have 3 settings. 3 speeds is just left over lingo from the old.
@HeatGeek yes but most good pumps also have constant speed settings as well as PP and CP. If that's the case, there's nothing stopping the designer using a constant speed setting, allowing the pump to remain on a constant curve and thus, balancing the primary and secondary circuits.
Hi dude, thanks for the great video. I'm having a new sealed system oil boiler installed (grant vortex 26-46) and trying to work out if I need an LLH. It's a big old house (kind of a maisonette + a flat) with rads on two heating zones already + one old vented cylinder, no UFH. Rads T off in 10mm copper from 22mm main feed so flow a bit low perhaps. Does the zoning stipulate LLH as the way to go or is it wasted cash and efficiency. Your opinion is much appreciated!
wow how did you even learn all this !!!
Basic bits from cibse design guide.. after that alot of Thought experiment!
Hello, I have a small technical question regarding my setup, which consists of 2 heating appliances in cascade, and 2 circuits directly connected to the LLH (one for radiators with 4 floor pumps, and one for a 800L DHW tank). I am constantly monitoring temperatures on each input and output flow (via ebusd, openhab and grafana), and I noticed it is really inefficient (given the variable flow rate on the heat consumers side). Is it feasible to replace the LLH with a plate heat exchanger? Thanks a lot, Cristian
Excellent .. 9kw Under Floor driven by 28Kw Boiler ? I didn't understand that .. Is the boiler a modulating boiler running on 1/3th throttle ? Is it that size boiler come with a big flow rate, so is pumpable ?
Ufh requires flow 3 times the rate of a gas boiler. If the boiler is oversized by 300 % some installers are connecting direct. I've not done this myself as I'm uncomfortable with the idea but those who do report success.
Great video 👍
12:32 Interesting to see you say an UFH manifold without hydraulic separation and on a radiator system needs a close-coupled tee. If the flow the UFH manifold takes from the primary flow (once heated through) is not enough to rob the radiators, and the sum of the startup UFH flow + radiator flow does not exceed the boiler maximum, I'm a bit confused as to why you'd need a close-coupled tee. My concern would be that just putting in a close-coupled tee as you suggest at 12:40 would throw 70°C water back into the boiler return as well as throw the system out of balance.
Any chance you could tell me what it is that I am misunderstanding please?
Hi. The cct leg would need a balancing valve and be balanced to delta t 20 drop.
@@HeatGeek Thanks. That makes sense. I like your video, by the way: nice to see someone else putting some serious thought going plumbing and you explain it well. I look forward to watching more of your stuff.
@@johnbull5394 thanks. Check put heatgeek.com too.. lots of articles there
@@HeatGeek Ha, that's where I found your videos :)
Great channel👍
great vid. i want to install a monoblock heat pump but the companies tells me i have to need install at least 100 liter tank , (hydrolic separation) so the pump can defrost outside.. today i have a split system and the pump outside defrost when the pump is off not like a monoblock hp. Anyway i dont have a tank on this system today, i guess its because its a split and dont need defrost,? my house had floor heat only 250 m2 , but i wanted to skip tank? it seems when i listen to you i can , my house need 9 kw to 0c outside and 15 if its colder.. so what do i do , maybe a smaler hydrolic separator like the ones you talk about?
If the volume is in the pipework younwknt need additional
A few years ago I attended a school which had had a new boiler and LLH installed in a particular block. I had to go several times as there was a pressure fault, but I never caught the system “in fault”, it would always reset and run up no problem. I came to the conclusion that the LLH pump which was a substantial one, under certain conditions was adversely working against the boiler pump causing a low pressure alarm which I could reset upon arrival because the “conditions” had reverted back to “normal”. I submitted my report but, as with large companies, engineers never get involved with problems after that, so I don’t know what was the outcome ( which I hate because many engineers had been there before I was asked to take a look, and I believe in job ownership and I like to see jobs through ). Has anyone ever experienced similar issues 😁
checking bad boiler installation so now i am not getting enough circulation to loft area (fitted is a worcester bosch 42kw) bosch recommends adding another pump, but did not mention LowLoss header . in the past it was easy to replace just the pump head but WB do not do a 8m head, i can get an 8m head from grundfos BUT are they still interchangeable (bosch pump head to grundfos 8m head on boiler housing hopefully you can help
Wouldn't an increase in temperature difference mean a more efficient heat transfer?
Great video 😎👍
Thanks bud
Does the pump on the underfloor heating put less presure on the main pump ?
Additional pumps always help reduce the load
Awesome mate 👍
Thanks 😁
Brilliant video! I had to watch it twice as the humans at the top of your tshirt kept distracting me!😁😁😁
Cheers Doug!
Hello mate just a quick question for u am doing and install 5 120 kw boilers I have 4 vt circuits off low loss there is no bms being installed what’s the best way to wire the mixing valve can I wire the vt valves of a weather comp as can’t weather comp boilers as have 3 cylinders off this
Well your going to have to wire them in somewhere so you either need a native controller or you use autonomous valves that have the controller built in. Who specked it?
Was speck by outside company thanks mat il look for those valves with built in controls thanks
A low-loss header can eliminate boiler interlock control, having TRVs on all rads. No central thermostat space heating control switching out rooms when they are calling for heat. Two radiator heating zones with each having its own time clock, flow switch, and smart variable speed pumps - no zone valves. The combi boiler loop pump is on a fixed speed (with ERP may not be possible on many boilers these days).
There will be temperature _distortions_ when TRVs close and say a timeclock switches off a zone. The boiler always gets more than adequate flow - with only one TRV slightly open the flow may be too little through the boiler without a header, the header prevents that. Auto-by-pass valves are a cludge. It is simple, effective and reliable using the header with superior comfort control.
Liquid is coming out of the air hole (?) at the top. How can we stop this?
Nice one 👍🏻