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VoltzElectrical

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I have no experience in the installation or fault finding of, central heating systems.

I don't do, and have rarely done, domestic work.

I volunteered recently to look at an elderly lady's situation whereby the system had been installed, then altered as the room stat was relocated from the garage (causing the heating to come on more than was necessary) to the other side of the wall into the kitchen. Since the alteration, apparently the cylinder stat no longer works correctly so the hot water is scalding.

I opened up the 10 way junction box (double back box with blanking plate) to find a rats nest with nothing labelled.

I put the cover back on and said I would research it.

TBH I am going to tell her to get someone in who has experience with heating systems as I don't want to get into something I have no experience in.

My question is - where is a good source of information on the different types of heating systems? I have all the Honeywell wiring diagrams, but I feel I need to start with the basics. I couldn't even establish what 'system' was installed in the property, although from the diagrams I suspect 'S Plan'.

What does 'S Plan' or any of the others even mean? Who decides the allocation of a lettering system of the types of 'plan' ? Is there a logic to it?

I understand that it's a 'call system' but other than that I would like to further my learning if nothing else than I like to learn. I have come through a learning system that has not covered this area.

If anyone could direct me to a learning resource other than the Honeywell schematics, and by this I mean BASIC (lol) I would be grateful.

Voltz.

PS I did PM you Geordie but either your inbox is full or>>>>
 
The S plan uses separate motorized valves for CH and HW
The Y plan uses one mid-position valve at the Y ​junction, where HW and CH paths separate.

These above are the most common.


If the hot water is scalding it could be a coincidence it happened when you moved the room thermostat. check the cylinder thermostat is switching off with your continuity tester and turn the cylinder thermostat up and down to check its making and breaking. If it's a s-plan the valve could be seized open and constantly firing the boiler (check for voltage on the orange of the hw valve with the hot water turned off at the programmer).


I pretty much taught myself heating wiring. The sequence of how it all switches 1st, then how a 3port and 2port valve works, Once you learn this you can work out the rest.


The sequence for a s-plan- programmer switches thermostats on, thermostats switch the valves,valves switch the boiler for heating and hot water.


Y plans are a little more complicated as you have hot water off/ satisfied connections on programmer, valve and cylinder thermostat but if you learn how a 3port works then you realise why.

http://www.gasheating.co.uk/Mid-Position-Valve.html
 
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might help might not depends on what your looking for :)

[video=youtube;XIY_T6mx7KM]https://www.youtube.com/watch?v=XIY_T6mx7KM[/video]

[video=youtube;vFCOmg3GiZQ]https://www.youtube.com/watch?v=vFCOmg3GiZQ[/video]
 
might help might not depends on what your looking for :)

[video=youtube;XIY_T6mx7KM]https://www.youtube.com/watch?v=XIY_T6mx7KM[/video]

[video=youtube;vFCOmg3GiZQ]https://www.youtube.com/watch?v=vFCOmg3GiZQ[/video]

What ever you do, do not take this blokes advice on the video about the 3port valve because it's wrong and is the biggest load of cr@p I've ever heard!

white is connected to the call for heat (SL) from the room thermostat and grey is connected to HW off on the programmer and HW satisfied on the cylinder thermostat.
 
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What ever you do, do not take this blokes advice on the video about the 3port valve because it's wrong and is the biggest load of cr@p I've ever heard!
Goota agree, that's a terrible video and description of a 3 port valve! It's easy for heating engineers like him though...although he doesn't seem to know a thing about it lol...terrible video.
 
Hi all.

The cylinder stat was wired up backwards so always on i.e. bypassed. All working ok now with that.

Now there is a problem with the Horseman Centaurpuls C21 programmer. The central heating will not work on the timer. I can only get the CH working by leaving the programmer on the off position which sends a live feed to the room stat so the CH must be controlled manually using this. If I put the CH on timer/ all day/ 24 hrs it switches the live feed to the room stat off and the CH won't work.

What is going on?

Thanks in advance.
 
I should add that the link in the back of the programmer looks like it is still in, except that it's black not blue as stated in the instructions? I don't know what system it is i.e. fully pumped or gravity fed.
 
I should add that the link in the back of the programmer looks like it is still in, except that it's black not blue as stated in the instructions? I don't know what system it is i.e. fully pumped or gravity fed.

do you mean is it gravity or pressurised ???

does it have an expansion tank in the loft should be no bigger than 2x2 (ft) if it does its gravity if not its pressurised,

or fully pumped or gravity fed. does it have a pump for the heating
 
do you mean is it gravity or pressurised ???

does it have an expansion tank in the loft should be no bigger than 2x2 (ft) if it does its gravity if not its pressurised,

or fully pumped or gravity fed. does it have a pump for the heating

Gravity has nothing to do with an expansion tank in the loft!
An 'open vented' system is one which has a header tank with an open vent pipe at the highest point of the system.
A 'sealed system' has no open vent, instead it uses a pressure vessel to take up the expansion in the water.

A 'gravity' system is one where the primary feed to the hot water cylinder is not pumped, the heat gravitates through the pipework.
 
Gravity has nothing to do with an expansion tank in the loft!
An 'open vented' system is one which has a header tank with an open vent pipe at the highest point of the system.
A 'sealed system' has no open vent, instead it uses a pressure vessel to take up the expansion in the water.

A 'gravity' system is one where the primary feed to the hot water cylinder is not pumped, the heat gravitates through the pipework.

gravity filled :)
 
i wanted to keep it simple as he has no experience with central heating systems anyway back on topic :D

There's no point trying to simplify something by making up non existent terms. If someone wants to learn then they will be far better off learning the correct terminology than a load of nonsense.
 
Hi all.

The cylinder stat was wired up backwards so always on i.e. bypassed. All working ok now with that.

Now there is a problem with the Horseman Centaurpuls C21 programmer. The central heating will not work on the timer. I can only get the CH working by leaving the programmer on the off position which sends a live feed to the room stat so the CH must be controlled manually using this. If I put the CH on timer/ all day/ 24 hrs it switches the live feed to the room stat off and the CH won't work.

What is going on?

Thanks in advance.

Have you changed any of the wiring in the programmer as it sound like CH is terminated to CH off and not ch on as it should be.
 
Have you changed any of the wiring in the programmer as it sound like CH is terminated to CH off and not ch on as it should be.

No. All I have done is get the HW working properly on timer and stat controlled rather than being on all the time. The system was originally controlled via a wireless stat but that didn't work properly. Then the lady had someone in to put a room stat in but they put it in the garage so the CH was coming on all the time.

Then the lady had someone else in to move the room stat into the utility room the other side of the wall but she said they didn't know what they were doing and left her with scalding hot water on constantly so she switched it off and was just using the immersion as and when.

Last weekend I sorted that and she's happy with the water temp and timing. At the moment she has to manually control the CH as the programmer switches the room stat off when it comes on. The CH is now 'off' on the programmer which leaves the room stat on. When she doesn't want heating she switches the room stat right down, then back up when she wants heating.

I don't know if the wireless original programmer has been replaced with one suitable for the system. It says in the instructions that if the system is partially pumped then you can't have CH without HW and the link has to be removed, but it looks like it is still in.

I think the system works, all the wiring for s-plan looks correct but the programmer is working the wrong way around? If that is the case, then what do I need to do to put it right?

Sorry for the long post, but that's the long and short of it.

Thanks again.
 
No. All I have done is get the HW working properly on timer and stat controlled rather than being on all the time. The system was originally controlled via a wireless stat but that didn't work properly. Then the lady had someone in to put a room stat in but they put it in the garage so the CH was coming on all the time.

Then the lady had someone else in to move the room stat into the utility room the other side of the wall but she said they didn't know what they were doing and left her with scalding hot water on constantly so she switched it off and was just using the immersion as and when.

Last weekend I sorted that and she's happy with the water temp and timing. At the moment she has to manually control the CH as the programmer switches the room stat off when it comes on. The CH is now 'off' on the programmer which leaves the room stat on. When she doesn't want heating she switches the room stat right down, then back up when she wants heating.

I don't know if the wireless original programmer has been replaced with one suitable for the system. It says in the instructions that if the system is partially pumped then you can't have CH without HW and the link has to be removed, but it looks like it is still in.

I think the system works, all the wiring for s-plan looks correct but the programmer is working the wrong way around? If that is the case, then what do I need to do to put it right?

Sorry for the long post, but that's the long and short of it.

Thanks again.

Take the programmer off and make sure the ch on is connected to number 4 and not number 2.
 
http://www.partscenter.co.uk/wcssto....all/ti/on/Horstmann_C21-C27_Installation.pdf

Right, I think that the system I am 'working' on is number 7 in these instructions (which were not left with the customer).

I will check that the outputs in the programmer are correct then.

Thinking back there were 2 wires connected into the programmer but left live unconnected in the wiring centre. I think these need to go back in somewhere!
 
http://www.partscenter.co.uk/wcssto....all/ti/on/Horstmann_C21-C27_Installation.pdf

Right, I think that the system I am 'working' on is number 7 in these instructions (which were not left with the customer).

I will check that the outputs in the programmer are correct then.

Thinking back there were 2 wires connected into the programmer but left live unconnected in the wiring centre. I think these need to go back in somewhere!

Do you know what room thermostat it is ?
 

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