Hot water but no central heating (after summer of no-use)

[pjblink]

Boiler is an Ideal Classic NF.

Everything works fine when the controller calls for hot water. Pump works, boiler lights up, tank gets up to temperature and stops everything.

When i call on the controller for central heating, i get absolutely nothing. Boiler doesn't make a noise, pump doesn't kick in. The room thermostat makes the click when i rotate it to on/off, but has no effect. I can get heat in the radiator if i call for hot water and manually open the motorised valve.

If i manually open the valve and turn only the CH on, i still get nothing.

Does this sound like the wall thermostat?

Havn't used the central heating all summer, and had a chilly morning the other day so have only just noticed it. It all worked fine at the start of the summer.

Thanks, Patrick

 

[seco services]

no it sounds like the motor has failed in the valve.

 

[pjblink]

Even when i manually open the valve, and select my controller to switch on the central heating i get nothing though...Bear with me as i don't know much, only what i've researched about similar issues.

 

[D_Hailsham]

no it sounds like the motor has failed in the valve.

Seconded.

When hot water only or hot water and heating is selected the boiler is turned on/off by the hot water cylinder thermostat. That's why you can get heating by moving the valve by hand.

When heating only is required, the boiler is controlled via switches in the valve. As the motor is not working, the valve is not opening fully so the switches do not close.

You can get a new motor from B&Q for about £20.

 

[seco services]

manually opening the valve will only select mid position.
then the live to pump/boiler will come from the cylinder stat.

if the motor has failed you won't get the valve over to heating only to activate the microswitch to turn the boiler/pump on.

put heating on only if you have power on the white wire and the motor is not opening the valve the orange won't get power to the pump/boiler.


beat me to it.

 

[pjblink]

That's ace, thanks guys. I'm renting, but i don't want it to cause the landlords to spend too much time checking it out themselves so it's fantastic i can now point them straight to the cause.

Any way to test it?

 

[D_Hailsham]

Any way to test it?

Yes. Listen to the motor.

Turn Hot water OFF, Heating OFF, Room thermostat to MIN

Move the lever on the motor from Auto to Man. YOu should feel resistance as it is opening the valve against a spring. If no resistance, the valve is sticking. Let the lever return to Auto.

Turn Heating ON.

Get someone to turn the Room thermostat to MAX while you listen to the valve. You should hear the motor running as it opens the valve.

Check the valve has not opened by doing the lever test. (The lever will be floppy if the valve has opened.) If this is the case, then the motor is OK but the switches in the valve are faulty. Get a new actuator.