Radiators running hot even when thermostat is off

[Klaus_K]

The subject says it all really. Even though the nights are getting colder, this issue is making the house uncomfortably warm. <== me overheating.

The system has been fine for several years now, so I'm not sure what the problem can be.

Note that it's not simple convection in radiators near to the hot water cylinder - it's the whole house at full blast. At first I though it was a faulty thermostat, but I replaced that and the fault is still there.

The only way I've found of stopping the problem is to turn the heating off at the programmer, which seems a bit extreme

Can somebody confirm that there is no way that the pump should be running if the thermostat is 'off'?

KK

 

[kevplumb]

View media item 11149 View media item 11148
any of these

 

[seco services]

The only way I've found of stopping the problem is to turn the heating off at the programmer, which seems a bit extreme

then the stat is not doing anything as in controlling temp.

 

[picasso]

Can you give a bit more information about your system, what programmer, room stat, 2 or 3 port valves ect

 

[looneyfitter]

Can you give a bit more information about your system, what programmer, room stat, 2 or 3 port valves ect

as he said. but also, where is the stat? have you had cavity insulation fitted recently? Have you had any alteration work done

If you have no valves then the stat should control the pump. The hot water will be working off gravity. If you turn the stat down, does the pump stop?

Gareth

 

[Klaus_K]

OK, here we go...

• 
  Boiler: Alpha CD24R
  Programmer: Honeywell ST6400C
  Valve: Three port valve
  Thermostat (new): Sunvic RF programmable

Last night I physically removed the thermostat, leaving the circuit open, and set the programmer to 'no heating', yet the problem still appeared this morning. Does that mean it's the valve? If so, how best to fix it?

Thanks

 

[Klaus_K]

where is the stat? have you had cavity insulation fitted recently? Have you had any alteration work done...
...If you turn the stat down, does the pump stop?
Gareth

• 
  The stat is in the hallway, where it has always been (although I've got an RF one now, so that I can move the sensor to the lounge).
  I've had no alteration work done.
  As you'll see from my earlier post, the stat doesn't seem to have any impact on the heating behaviour - i.e. it doesn't even need to be there.

 

[picasso]

Its gotta be the 3 port valve, you can change the head only without draining down or if you want to be sure change the whole valve.

 

[Klaus_K]

Sounds like a new valve would be the best step forward - thanks for all of the help/advice on this.

As an aside: what are the risks of just replacing the head and leaving the valve in place? How likely is it that the fault is in the valve and not the head?

This site & forum really is a marvel - getting advice from places as far apart as Tennessee, Essex and Merseyside. Warms the heart

 

[kevplumb]

if you remove the head you should be able to turn the valve spindle by hand if not the valve has had it

while you have it off if you switch hw/ch on / off you should be able to see the d shaped hole in the head motor over

 

[Klaus_K]

Will any head work with any valve or do they have to be the same model etc?

 

[picasso]

has to be the same make and model.

 

[kevplumb]

same model there will be a number on it

 

[looneyfitter]

Right turn heating off and let it go cold. Goto your valve, and take the head off it. Make a note of the spindle position and turn the heating on. You should be able to turn the spindle and feel the pipework a metre away from the valve to see it it passing. Port A is Heating and Port B is hot Water


No pint buying a new head until you have checked this as you will be wasting your pennies.

HTH Help