HW causes CH also - why?

[PeterGroom]

HI there

I hope someone can point me in the right direction.

When my Thermostat CH is off but my HW is on, this causes the rads to come on also.
I think it is the three way valve close to the pump.

Am I on the right track?
Is it likely that I can just replace the syncron motor in this unit, or do I need to replace the whole thing having drained the system first?
If so, what do I ask for at the plumbers merchants.

Thanks in advance

Peter

 

[oilman]

You could replace anything you like, but if you want some advice we want some information, lots of it.

Has it always done this?
If not when did it start........etc etc etc

Just look at the posts at the top of the forum and then come back with all the information.

 

[breezer]

oilman means see this

 

[oilman]

I wasn't going to make it THAT easy.

 

[PeterGroom]

Hi

The boiler is a Gas Potterton/Myson I believe
No changes have been made to the system recently
I think this is a new problem, but by that I mean that I just noticed it.
When the CH is off but the HW is on, this causes the rads to heat up also.

I hope this additional information is of use.

Thanking you in advance

Peter

 

[ChrisR]

Most 3 way valves return to HW only position by spring pressure, a few motor both ways. So we need to kknow the valve type/number. Try the lever on the end if it has one. If you can hear/feel the spring working, the valve head may be be sticking/bust or the valve's wet internals may be "letting by".

 

[PeterGroom]

Thanks for that Chris.
I looked at the lever which was limp and apparently not moving anything.
I took the unit apart, removed synchron, to discover that the pin locating into the actual valve was very stiff. I think this stiffness had caused the assembly to jump out of its cog positions. Once Id freed up the valve pin to a smooth motion, I re assembled the cog bacvk down to locate it into the movement assembly and the lever is now back in play.
All now seems well with the HW on and nothing routing to the rads except when its called for.
TRIUMPH

Thanks for your help.

Peter