HW Preheat Problem With Glow Worm 30 CXI

[2point8ghiax]

Recently, the hw preheat facility on my Glow Worm 30 cxi has started playing up. It comes on more often than it should and sometimes turns itself on and off in quick succession (start-stop-start). Sometimes it will run for 10 mins or more, sometimes continuously, other times on and off, maybe on for a second, then off again, then back on. Also, the rads get slightly warm when it has been on a while.

I have turned preheat off for now, which has stopped the boiler coming on when it feels like it.

Is this likely to be something simple, eg. the thermostatic sensor that controls the preheat, or being a pile of s**t boiler, is there more to it?

 

[Youllneverguess]

Have you checked for dripping taps?

 

[Agile]

It could be an intermittently faulty sensor, water leaking onto it or just the plug connectors oxidised.

You could measure resistance cold and remove and refit connectors.

Tony

 

[2point8ghiax]

Thanks for your replies.

No dripping taps.

Thanks Agile, will have a look at sensor. What resistance should I be looking for cold?

 

[Agile]

Probably a nominal 10 K at room temps.

Tony