central heating systems help!

[VoltzElectrical]

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>>>>

 

[Leesparkykent]

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

 

[Corbs]

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]

 

[Leesparkykent]

DVDs | Mr Combi Training

wiring & controls DVD or book available to buy here.

i know its a little steep but it cheaper than a course.

 

[Leesparkykent]

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.

 

[123]

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.

 

[UNG]

Worcester Bosch do a good wiring guide on their website https://www.worcester-bosch.co.uk/cache/file/482/gas-boiler-wiring-guide.pdf

 

[VoltzElectrical]

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.

 

[VoltzElectrical]

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.

 

[Corbs]

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

 

[davesparks]

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.

 

[Corbs]

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

 

[davesparks]

gravity filled

No such thing, it is called open vented.

 

[Corbs]

No such thing, it is called open vented.

i wanted to keep it simple as he has no experience with central heating systems anyway back on topic

 

[davesparks]

i wanted to keep it simple as he has no experience with central heating systems anyway back on topic

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.