Lack of heat Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[stucampbell007]

Hi, guys.

I have just replaced a Drayton motorised valve which had leaked into the actuator, causing the CH to come on whenever the hot water was on.

I drained the system, as detailed on here, changed the valve, refilled the system - no leaks on the new valve - and the CH is not coming on with the hot water any more

However, when the CH is turned on the radiators are not getting warm and the boiler is turning itself off after about ten minutes.

Any ideas?

[Bob Plum]

Is the pump running? Have you managed to disconnect or wrongly reconnect the pump when you did the electrical part of the valve replacement?
If the pump isn't running, disconnect it from the control box, put a 13A plug on it and then plug it in - if it works, then the connections are wrong somewhere. If it doesn't work, you have another job to do.
If it does work and the radiators don't get hot when the heating is switched on, you have a seriously bad air-lock.
Be careful to make sure the pump is or is not running at each test - it should run very quiet so it isn't always very obvious - the old screwdriver held to the casing and the other end of it to your ear can be helpful.

[Steve the gas]

Hi,
sounds like boiler overheat stat kickin in, prolly air in there,if you are able bleed the pump.If boiler has auto air vent make sure this is operating.

HTH