Central heating puzzle.

[la poste]

Greetings.
A friend of the family has a Y plan central heating system (I think that's what it's called)
He has a ACL lifestyle model lp522 programmer I am not sure of the make of the boiler.
His system will work on CH (central heating) and hot water together, hot water on it's own but not CH on it's own. To get the CH working he has to switch the programmer to hot water and CH together.
He recently had the three way valve replaced but this has not cured the problem.
Central heating is new to me but I am fairly confident with electrics.
I was wondering if anyone could provide a good link or two to teach me about this system or whether anyone has any ideas about what this problem could be.
Thanks.

 

[tamz]

It has been wired wrong. Common problem with Y plans.
It needs a wire from the HW off (terminal 1 of the programmer) to give power back to the grey wire of the valve. Probably will need a new cable to the cylinder stat too as it needs 3 wires (common call and sat).
Get a Y plan wiring diagram. It is straightforward enough to follow if you do electrics.

 

[la poste]

Thanks for the reply you were spot on.
There is one thing I am not sure about though.
On the back of the programmer there are four terminals.
HW on, HW off, CH on, CH off.
Now according to the wiring diagram I am supposed to use the HW on, CH on and HW off terminals and wire them into the system.
Does anyone know what the CH off terminal is for and whether it is used in a Y plan central heating system or is it there to be used for another system other than Y plan?
Thanks again.

 

[gasmarc]

I dont think you use the CH off as the room stat does that but i maybe wrong

 

[tamz]

Ch off does not get used

 

[SafeGasInstall]

Share with us were to down load a
S and Y plans diagrams!

 

[tamz]

Here

Y Plan


S Plan


C Plan

 

[Billy Bob Bob]

tamz mate could you send that to me so i can print it out for dave the apprentice? not buying him the Honeywell book ,think you can do it via email

 

[tamz]

Whats your email?

I found it. it is on its way

 

[Billy Bob Bob]

[email protected] cheers tamz i can print this off for him he may learn something(i hope) he is showing a flair for electrical work

 

[gasmarc]

i think you can download stuff from honeywell also