I used to love wiring heating systems, did them for several plumbers who just left the wires dangling. Made my own terminal boxes up back in the 80's with fixed terminal blocks numbered and ALL the terminals were big enough to get all the required cables in, plenty of wiring space. The neutral was the issue, for each separate part of a control, pump, valve, boiler or whatever else there was a neutral so sometimes there was almost 10 neutral wires and any manufactured terminal box never had a big enough connector, same with the earth. I did an underfloor heating system once with its dedicated controller, 15 terminals outgoing for various parts, stats, etc, and only 1 earth and neutral terminal. Terrible design with no thought for the person installing it or fault finding. I have to say you were brave attempting to wade into that birds nest of wiring, that is an atrocious job, you did well. 🎉
Not too bad really, 4 outputs would control the zone valves turning on and the relays on the valve would be wired in parallel providing the power for the pump and boiler assuming it’s a 240v switched output to the boiler. The 4 zone controls would either be thermostats or relays from something a bit more advanced like a evohome or other computer based control system. I’ve used Wago topjob S din rail units to keep things neat and tidy. They have bridging connectors if you need to parallel connect and are highly flexible for whatever you need to make up. Added a din rail to a recessed box and flush mounted mine. Nice neat and documented.
The three terminals on the micro switch will be a common, normally open, normally closed. That give the choice of the switch turning flow-off or on when actuated. 👍👍
Great to see roger highlighting the all to appallingly bad standard of wiring of heating controls. No wonder the public barley understand them if the trade just jam all the wires into too small a terminal block and hide it in a plastic box. Out of site out of mind. I’m surprised there isn’t an industry stand wiring terminal block that can cope with the most common heating system plans and has everything labelled and tidy. It’s been done for mains wiring for years. If the work was photographed and logged then I’m sure the work would be finished to a much higher standard and cost only a bit more. I used to work in HVAC commercial and you knew your work would be judged so you made an extra effort to make it look smart and tidy. Some pipe work and wiring install I saw were works of art!
Hi Roger As a retired electrical contractor , I can’t for the life of me understand why a qualified electrician can’t work out how a simple bit of kit like a motorised heating valve works . And as for the mess of wires that you showed , it’s beyond belief . There will be 240 / 230 volts rummaging around in that rats nest , even if it was in some sort of enclosure . You would spend half your time working out what did what . I’m sad to say that there is a lot of incompetent individuals still out there . And the only reason people are not dropping like flies , is the advancement of RCD technology . God only know what these people would do , if involved with a three phase installation . Probably they would be burnt as crispy by the end of their shift . 230 / 240 v usually you get up and walk away , 400 / 415 v and it’s usually good night Vienna . Best wishes and kind regards as always
and why folks dont label stuff up as they go is beyond belief, it take 15secs or less to put a label on something but can save hours at a later date. As you say goodness know how some would get on with something like a star delta 3ph starter !
The internals of a motorised heating valve is quite complex as it uses micro switches resistors and a diode arranged in such a way to make the motor stall and hold its position against the return spring when energising and de energizing the appropriate wire or wires, so its not so simple
This is actually easy to do DIY. Some great diagrams available on flameport, had same issue Plumber installed new unvented and had my hot water coming on with the heating, tore it all out and redone it myself and whacked a Hive in at the same time. Going from scratch is actually far easier than tracing every wire back.
Hi Rodger, my “wiring centre” was a product of 1980s bodging. A small single gang backbox and terminal blocks. Not as bad as the one you have here though. To cap it all it was put at the back of the airing cupboard. The power was on the wrong side of the side and there was no space to put in the Honeywell evohome relays so not wanting cabling or sucting across the cupboard I decided to build a remote connection box from wago Topjob S din rail connectors. So I have a nice recessed din rail main unit with all the power nicely set up. In addition I’ll be adding monitoring so I’ll be able to see when the zone valves are getting power and when the pump and boiler get power with a temperature probe and a height detector for the top up tank incase it goes dry or overflows. All diagrammed out and colour coded. Dead easy to follow.
Roger I can remember my first central heating fault. New years eve and the boiler would not stop firing. Took the central heating clock off and the boiler was still going (live feed to the boiler). It was a micro switch in the motorised valve. And I bought micro switches and fitted them. The fault finding was in the early hours of the morning, not ideal.
Very interesting Roger, good video. I think I'd be instantly put off by the volume (and mess) of wiring in the opening part of the video. Once I'd sat down and had a look, and if I understood what each component did, then I'd probably be fine. I'm guessing some electricians have little experience of the functional components of the heating system, so possibly just prefer not to get involved.
I changed a synchron motor on the central heating zone about a year ago. The problem was the boiler was switching off before the room stat had reached the required temp, sometimes it would start up again 10 or 20 mins later. Anyway it seems the synchron motor was intermittantly de-energising. It was 30 years old so had done well really. The one on the hot water still works ok.
When eventually we move to our next house, I plan to augment any wiring centre with a shed load of tell tale LED lights so that monitoring the situation is made really easy. Then the next stage is to further enhance that monitoring by making the data available on the web. It will probably never happen, but I can dream... :-)
The microswitch is a standard item and usually has 3 terminals. Common (C), Normally Open (NO) and Normally Closed (NC). In your video the unused terminal will be the NC terminal that opens when the stat trips on. Easier to see on a diagram.
There are two types of motorised valves for heating control. A 2 port one for hot water and a second 2 port one for central heating. There is also the 3 port valve which controls hot water at the mid position which then motors to full open which supplies central heating. The 2 port valves are completely separate but yes, the 3 port valve can give the symptoms you described.
When the motor moves to correct position it switches the mains power through to the boiler & pump. Duff motor wont switch boiler on. Same with thermostat on a hot water cylinder. Switching mains to boiler. Very basic & simple ideas just loads & loads of wires.
New reputable 3 port motorised valve fitted exact wiring as original one. New heat exchanger and new fan. Can only turn heating on if I turn hot water on. The grundfos pump activates when I select hot water override but does nothing if I select heating override why?
I'm not electrician or plumber, but managed to take out a system and put in a wiser system for my 2 zone house. Wasn't that hard as long as you follow the directions. It's hardly rocket science, but I get why plumbers wouldn't do it if you have to be part p registered. Elecchickens shouldn't really have an issue with these. As far as I'm concerned its something simple they should all be doing
I have replaced faulty micro switches, in these valves, micro switches cost pence, one other challenge with heating / hot water wiring is the inconsistent use of wiring colours, open them up and earths are used as Live's!, please if you do have to use wiring with the incorrect colours ( inevitable as 3 or 4 core + earth cable is silly money) then label the wires in the wiring centre..
Jeez that wiring was worse than mine to work on . I change the zone switches myself when they go , my heating one was breaking every couple of years , but I eventually found a tiny leak of inhibitor out of the valve , it was seizing up ,and not letting the spring switch turn off and breaking them .
I used to love wiring heating systems, did them for several plumbers who just left the wires dangling. Made my own terminal boxes up back in the 80's with fixed terminal blocks numbered and ALL the terminals were big enough to get all the required cables in, plenty of wiring space. The neutral was the issue, for each separate part of a control, pump, valve, boiler or whatever else there was a neutral so sometimes there was almost 10 neutral wires and any manufactured terminal box never had a big enough connector, same with the earth.
I did an underfloor heating system once with its dedicated controller, 15 terminals outgoing for various parts, stats, etc, and only 1 earth and neutral terminal. Terrible design with no thought for the person installing it or fault finding.
I have to say you were brave attempting to wade into that birds nest of wiring, that is an atrocious job, you did well. 🎉
Not too bad really, 4 outputs would control the zone valves turning on and the relays on the valve would be wired in parallel providing the power for the pump and boiler assuming it’s a 240v switched output to the boiler.
The 4 zone controls would either be thermostats or relays from something a bit more advanced like a evohome or other computer based control system.
I’ve used Wago topjob S din rail units to keep things neat and tidy. They have bridging connectors if you need to parallel connect and are highly flexible for whatever you need to make up. Added a din rail to a recessed box and flush mounted mine. Nice neat and documented.
The three terminals on the micro switch will be a common, normally open, normally closed. That give the choice of the switch turning flow-off or on when actuated. 👍👍
And they are usually labelled as "C, NO, NC".
And if present the NC wire is white.
Great to see roger highlighting the all to appallingly bad standard of wiring of heating controls. No wonder the public barley understand them if the trade just jam all the wires into too small a terminal block and hide it in a plastic box. Out of site out of mind.
I’m surprised there isn’t an industry stand wiring terminal block that can cope with the most common heating system plans and has everything labelled and tidy. It’s been done for mains wiring for years.
If the work was photographed and logged then I’m sure the work would be finished to a much higher standard and cost only a bit more. I used to work in HVAC commercial and you knew your work would be judged so you made an extra effort to make it look smart and tidy. Some pipe work and wiring install I saw were works of art!
Hi Roger As a retired electrical contractor , I can’t for the life of me understand why a qualified electrician can’t work out how a simple bit of kit like a motorised heating valve works . And as for the mess of wires that you showed , it’s beyond belief . There will be 240 / 230 volts rummaging around in that rats nest , even if it was in some sort of enclosure . You would spend half your time working out what did what . I’m sad to say that there is a lot of incompetent individuals still out there . And the only reason people are not dropping like flies , is the advancement of RCD technology . God only know what these people would do , if involved with a three phase installation . Probably they would be burnt as crispy by the end of their shift . 230 / 240 v usually you get up and walk away , 400 / 415 v and it’s usually good night Vienna . Best wishes and kind regards as always
and why folks dont label stuff up as they go is beyond belief, it take 15secs or less to put a label on something but can save hours at a later date. As you say goodness know how some would get on with something like a star delta 3ph starter !
The internals of a motorised heating valve is quite complex as it uses micro switches resistors and a diode arranged in such a way to make the motor stall and hold its position against the return spring when energising and de energizing the appropriate wire or wires, so its not so simple
Well explained, thank you Roger.
This is actually easy to do DIY. Some great diagrams available on flameport, had same issue Plumber installed new unvented and had my hot water coming on with the heating, tore it all out and redone it myself and whacked a Hive in at the same time. Going from scratch is actually far easier than tracing every wire back.
Wait, so I don't have to have the house sweating just to have hot water???
Who should i call? What should I say?
Hi Rodger, my “wiring centre” was a product of 1980s bodging. A small single gang backbox and terminal blocks. Not as bad as the one you have here though. To cap it all it was put at the back of the airing cupboard. The power was on the wrong side of the side and there was no space to put in the Honeywell evohome relays so not wanting cabling or sucting across the cupboard I decided to build a remote connection box from wago Topjob S din rail connectors.
So I have a nice recessed din rail main unit with all the power nicely set up. In addition I’ll be adding monitoring so I’ll be able to see when the zone valves are getting power and when the pump and boiler get power with a temperature probe and a height detector for the top up tank incase it goes dry or overflows. All diagrammed out and colour coded. Dead easy to follow.
Hi David
It would be great to have some pictures of that set up.
Roger I can remember my first central heating fault. New years eve and the boiler would not stop firing. Took the central heating clock off and the boiler was still going (live feed to the boiler). It was a micro switch in the motorised valve. And I bought micro switches and fitted them. The fault finding was in the early hours of the morning, not ideal.
Had tons of experience over 40 years of motorised valves. Honeywell best hands down. My dads point.
Very interesting Roger, good video. I think I'd be instantly put off by the volume (and mess) of wiring in the opening part of the video. Once I'd sat down and had a look, and if I understood what each component did, then I'd probably be fine. I'm guessing some electricians have little experience of the functional components of the heating system, so possibly just prefer not to get involved.
I changed a synchron motor on the central heating zone about a year ago. The problem was the boiler was switching off before the room stat had reached the required temp, sometimes it would start up again 10 or 20 mins later. Anyway it seems the synchron motor
was intermittantly de-energising. It was 30 years old so had done well really. The one on the hot water still works ok.
Roger is the Oracle! FACT!😇
Roger, if you lived & worked in MK, I would come and work with you! I would learn so much from a very talented person 👏🏽👏🏽👏🏽
When eventually we move to our next house, I plan to augment any wiring centre with a shed load of tell tale LED lights so that monitoring the situation is made really easy. Then the next stage is to further enhance that monitoring by making the data available on the web.
It will probably never happen, but I can dream... :-)
Hi Roger can you do a video on (bounce)and combi boiler?
The microswitch is a standard item and usually has 3 terminals. Common (C), Normally Open (NO) and Normally Closed (NC). In your video the unused terminal will be the NC terminal that opens when the stat trips on. Easier to see on a diagram.
Diyer here, so can a faulty valve actually stop a boiler from firing on the heating but allow hot water?
There are two types of motorised valves for heating control. A 2 port one for hot water and a second 2 port one for central heating. There is also the 3 port valve which controls hot water at the mid position which then motors to full open which supplies central heating. The 2 port valves are completely separate but yes, the 3 port valve can give the symptoms you described.
When the motor moves to correct position it switches the mains power through to the boiler & pump. Duff motor wont switch boiler on. Same with thermostat on a hot water cylinder. Switching mains to boiler. Very basic & simple ideas just loads & loads of wires.
New reputable 3 port motorised valve fitted exact wiring as original one. New heat exchanger and new fan. Can only turn heating on if I turn hot water on. The grundfos pump activates when I select hot water override but does nothing if I select heating override why?
Yes Roger, if only electricians would get themselves up to speed with 1960's technology when there was another kind of valve around. A glass one.
Just simply a trade making plumbing sound/ look interesting:) as always spot on
Those motor valves are they 24 volts AC or DC or you can get both?
240 volts
@@SkillBuilder that's surprising
I'm not electrician or plumber, but managed to take out a system and put in a wiser system for my 2 zone house. Wasn't that hard as long as you follow the directions. It's hardly rocket science, but I get why plumbers wouldn't do it if you have to be part p registered. Elecchickens shouldn't really have an issue with these. As far as I'm concerned its something simple they should all be doing
Was hoping to see multimeter being used, to see if wiring getting 'switched on' when called 😢
My valve is opening when the thermostat calls for heat but the boiler isnt firing up, is this the same issue?
There is a micro switch in the head, you can fix it.
I have replaced faulty micro switches, in these valves, micro switches cost pence, one other challenge with heating / hot water wiring is the inconsistent use of wiring colours, open them up and earths are used as Live's!, please if you do have to use wiring with the incorrect colours ( inevitable as 3 or 4 core + earth cable is silly money) then label the wires in the wiring centre..
What's the difference between a shoe valve and paddle valve? Are they interchangeable? Is one better?
I taught Roger that 😎
Jeez that wiring was worse than mine to work on . I change the zone switches myself when they go , my heating one was breaking every couple of years , but I eventually found a tiny leak of inhibitor out of the valve , it was seizing up ,and not letting the spring switch turn off and breaking them .
Why not use an actuator valve?
Wago wiring centres.
They don't do one big enough for four zones
Wasn't sure how many would squeeze, but is there not different sized ones, maybe a wago hybrid?
Those notarised valves seem to be the most unreliable part of heating systems it seems to me.
👌
We're you having a bad hair day Roger 😂
Every day is a bad hair day
Unfortunately many plumbers say you need an electrician and many electricians say you need a plumber
....when what you really need is a Skillbuilder😀
What sort of electrician can't follow a simple wiring diagram?
Bloody hell,
Poor design
I use a dymo priner for all the wiring, Makes life so much easier for the next person, or me in several years time
Hi Mark
I have one but I find a felt tip pen is easier
Complicated stuff 😳🤯🧱👍🏽