CENTRAL HEATING WORKING WHEN IT SHOULDNT!

[foxy1305]

I am totally perplexed on this one and hope somebody can help
I have a pretty standard pumped heating system. I have a programmer, room stat and gas boiler. The heating is set to timed, for on a 7.00am and off later in the day. The system has been fine set to off all summer, hot water working fine. My wife set the prog to boost one evening last weekend, and now we have a problem. The heating kicks in every morning, even when the programmer is set to off, and even when the room stat is set to 0. I have changed the programmer yesterday (Grasslin QE2) but this has made no difference. Howver when you move the room stat and the programmer into various positions and then back to off and 0 everything then shuts down as it should. With the room stat on 30 and the prog to off nothing happens, the prog to timed and the stat to 30 the boiler fires, the stat to 0 the boiler stops. So set to off on the prog and 0 on the sta all will be fine until tomorow morning at 7.00 when the boiler will fire again.
Any ideas?

 

[stardanny]

Do you have a two port zone valves or 3 port valve? In airing cupboard.

And the name of boiler?

Do the hot water come on at 7am as well?

Dan.

 

[foxy1305]

Stardanny. Its a Stelrad bolier (quite old but fine) The hot water side is working fine it would seem. Havent had reason to question this side of the system. No idea about ports in the airing cupboard I'm afraid. is this crucial to a diagnosis. How can I tell the difference

 

[stardanny]

A little silver or white box mount on tee or straight fitting, after the pump.

Sometime a sticking valve will cause th heating to come on when hot water come on.

A photos of airing cupboard would be nice.

Dan.

 

[foxy1305]

Thanks for the tip. I will check/take a photo tonight. If this is a possible fault is it a simple tap with a hammer to fix of replacement?

 

[foxy1305]

Ok so I have checked and I have a Drayton mid position actuator, MA1.
Switched hot water to off last night and thermostat to 0. This morning nothing came on. Moved the hot water to on and the boiler fired up. Moved room stat to 20, still no heating. But after a while it seemed the upstairs rads came on slightly. So if its is the actuator at fault? Is this repairable (with a thump from a big hammer!) or does it have to be replaced.
Or does the analysis point to something else being wrong. Sorry not sure how to add pics

 

[Armo74]

Sounds like the motor has probably gone and the valve is letting by a little that is why you are getting a little heat to your rads.

 

[foxy1305]

Is that the motor in the Drayton MA1 you mean, or something else?

 

[Armo74]

Yes, the motor moves the valve over when heating is called for and activates a microswitch which then fires up the pump and the boiler.