We've come home tonight to no hot water, no heat :-(
The pilot light on the boiler is lit, although it seems a little smaller than usual.
Rotating the boiler thermostat from off to fully on to off again seems to elicit the usual click but the burner doesn't fire.
Any thoughts anyone?
A number of thoughts, and probably to many to list at one time.
The boiler is not flaming but sounds as though it wants to, so the fault sounds like it is something on the main gas valve that's gone belly up. Three things on the main gas valve that cause this type of fault are the thermo-coupling from the pilot flame, the thermo-coupling detector inside the main gas valve and the solenoid inside the valve which opens to allow gas to flow.
What type of testing gear and hand tools do you have? You will need, at least, a multi-meter for electrical testing up to mains voltages (240Volts AC at 5 - 6 Amps). A good set of screw drivers and pliers and a set of spanners or small wrenches.
Got all of those and a spare thermocouple!
I haven't fitted the thermocouple as I thought the pilot light went out when that failed...
The sign of the pilot dropping in size may mean it hasn't failed completely, but is about to. However, my thoughts are that these should be replaced while the fault is evident, as they are now weaker than the repair you are about to commence. They are all related in their function, so it's best to replace when such faults occur.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.