Radiators warm up for 20 minutes, then cool down

[jezbo]

Starting from cold (in the morning), my radiators get warmer and warmer until almost hot, then after 20 minutes or so get cooler and cooler, not to warm up again until the next time it all starts from cold.

Anyone any idea where the problem might lie ?

 

[Bahco]

Faulty thermostat / set too low?

 

[jezbo]

There IS no room thermostat. There is only a dial on the boiler, and the pump, both of which I have set to MAX, but to no avail.

 

[weargas]

seeing as you haven't posted what type of boiler i will use my sidekick powers to predict you have a ....................................vaillant.

 

[jezbo]

There's no air in the rads, and I don't know what a thermocouple is. The boiler is a Baxi Bermuda, and it seems to be firing fine - there is plenty of hot water.

 

[ChrisR]

Could be faulty BOILER thermostat - hysteresis too high. The sensor goes in a pocket, iirc, which would be worth checking for dirt.

WHich Vaillant were you thinking of Weargas? vuw242/282?

 

[PEDANTICVINDICTIVEMAN]

Yes definately too much hysterias, needs a new boiler and roof on the house, plus you will need a new gas supply from the north sea to your house.

 

[kevplumb]

 

[jezbo]

Ha!
Turns out it was the little gizmo that diverts the hot water to the taps and/or the central heating. Fortunately it has a manual override so before it's replaced properly my house is toasty again