Why thank you Paul :)
I'm just trying to learn - and have never heard of that one before that's why I asked. I'd have checked the DHW thermistor as mentioned by another poster first - as well as the flow switch was working properley when a demand was made/water runs cold - then there's the...
sounds like a flow switch/diverter valve problem (depends what boiler it is) - that only makes contact with the switch when opened fully / more flow etc
I'd check the impeller is all ok and not blocked or loose - ryou need to emove 4 allen key screws to check that - after closing is valves or removing as mentioned by petit_pablo
Also check coil resistance
try bleeding a radiator at top floor level and see if water keeps flowing, if not could be a blocked cold feed, if there's water in the header tank.
also could be some air in the system so check that too
petitpablo: if air was in the system or a lack of water would that not cause an...
DHW Thermistor ok?
if as suggested a flow issue, check any filter/cartridge in your boiler on the cold inlet (that supplies the hot water to your hot taps) has not clogged up and resitriced the flow.
IF HOT WATER ONLY IS ON AND THE PIPES GET HOT TO THE HOT WATER MOTORISED VALVE - AND UP TO THE CYLINDER - IS THERE AN AIR VENT TEE'D OFF THE FLOW PIPE TO THE CYLINDER??
Quick question - I am trying to learn about boiler fault finding. I am gas qualified (since June) and have been working as a plumber for approx 3 years. I am working 1 day a week with a gas engineer (doing breakdowns/gas safety's/services etc) - would it be possible for me to join the...
check the pump and vent all air vents/rads in the system. make sure boiler stats is not set too high and also check water level in system is correct (vent highest rads and see if water squirts out) - does the boiler overheat after a certain time?
thanks a lot Kev for your help I really appreciate it. Have you missed a part of this post out about the gas valve or is it just my eyes playing up tonight :lol: