Central Heating Question

I have problem with my ch whereby first thing in the morning when the heating comes on it doesn't switch off when the thermostat temp setting is reached and continues to heat the house.

If I switch the heating off and then back on, either at the CH controller or the fuse box, it seems to start behaving itself. In that if I turn the thermostat down, I hear it click and the boiler stops. For the rest of the day it is usually intermittent and again and not switch itself off when the thermostat temp is reached. This means constantly regulating by switching the CH off & on again. When the heating continually runs, regardles of the thermostat temp, if I check the postion of the Honeywell valve unit, it is in the open position. When I switch the CH off this obviously closes and when I switch the CH back on it stays closed. When the CH is behaving itself and I turn the thermostat temp up and down, I can hear the valve opening & closing as required. But then later on in the day the problem re-surfaces.

My untrained thoughts are that it could either be a problem with the CH controller or with the Honeywell 3 port valve unit and it would probably be a case of swapping one or the other to identify.

Any trained thoughts would be welcome.

Thanks in advance.

Sovereign & Glenbury - thanks for the responses. Glenbury, when you say the valve head do you mean the cover ? The cover does have a bump at the back and inside the model is V4073A1039. I am fairly good at DIY - could I buy one of these and replace it myself ? I wouldn't consider it if it meant draining the system but a direct replacement I would tackle

3 Answers

Best Answer

In my experience the 3 port valve is the likely problem. problems with controllers are rare.If the valve head has a littlle round bump on the silver lid it can be replaced without draining the system.

Answered 18th Jan 2012

glenbury construction

Member since 16 Jan 2012

A common problem with motorised valve is that the mechanical part breaks(ie a rubber ball on an arm) and the ball that shuts of the flow goes in any position it likes, to prove it is not the controller turn both termostats up and switch hot water and heating on independently, to see if the boiler fires up and goes off,it is more likely to be the valve. In response to your 2nd posting, it is not the head that wants changing which is the electric side of the unit but the mechanical part so the system will need to be drained.

Answered 18th Jan 2012

sovereign plumbing and heating

Member since 23 Nov 2011

how old is the system as all have commented above your problem is the valve it is ether stuck ie the base brass side or the head is defective if its the base drain down required if just head it can be replaced but make sure you wire in like for like on colours in the wiring centre

Answered 16th Mar 2016

All Heating Solutions

Member since 14 Mar 2016

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