If we turn on the external heating thermostat, the central heating system works (boiler fires and radiators come on). If however we want hot water but no heating, we cannot get. This is a recent problem, everything was working before. We have the timer set to both heating and water and this is working (we get a red light) but it doesn't seem to be telling the boiler to fire. It is is glow worm boiler (not a combi) (sorry can't remember model)...
Thanks for any advice

Claire, September 2007

Sounds like the flowswitch is sticking or flowswitch sensor is not working. I had the same problem. Part cost about £70. On my Swiftflow75 it is located bottom left corner. I found I could take the sensor off and reposition it to get it working temporarily.

Jon, September 2007

Thanks for the prompt reply! Any idea how much these cost? I have a choice of paying a fixed price for fixing it (including parts and labour) or an hourly rate with parts on top. The cheapest option kind of depends on how much the part would cost (approx..)

Claire, September 2007

sounds like you have a faulty cylinder stat or diverter valve.

hi-spec plumbing, September 2007