Hello,
I have a Glow Worm 45 backboiler unit, which started to exhibit an interesting behaviour, which is at the moment being 'guessed' by me & an engineer so I may end up paying for N experiments to repair it.
1. Essentially, pilot light is OK, room thermostat makes boiler come on, eventually turns off the boiler -
2. right after the main burner goes out, the pilot light is turned off after a loud click.
3. I have to leave it cool a bit, pilot light re-lights perfectly, stays on... until next proper burn cycle terminated by the room thermostat, after which again pilot light gets turned off.
4. Vital clue: the pilot light does NOT get smaller, doesn't choke etc. prior to the click shutting it off for no visible reason ---> so it's not caused by any backdraft or ventilation problem, in which case I would understand safety system doing this.
5. as long as I only give the boiler a short burn, let's say a minute, it doesn't do this... pilot light stays on. I repeated this experiment via the room thermostat many times. But long proper burn cycle leads always to this shutting off of the pilot light after burner is turned off by room thermostat.
So it makes me believe it could be thermocouple? somehow when boiler heats up, it gets confused and then after main burner goes out, it believes also pilot light went out so decides to shut off everything? As my understanding is that the boiler overheat thermostat would only cut main burner, not the pilot light as well
Will be very grateful for any thoughts, it's been driving me and an engineer I consulted up the wall - and it therefore may mean several repeated repair attempts.... My working theory is to change thermocouple via a qualified engineer?
I have a Glow Worm 45 backboiler unit, which started to exhibit an interesting behaviour, which is at the moment being 'guessed' by me & an engineer so I may end up paying for N experiments to repair it.
1. Essentially, pilot light is OK, room thermostat makes boiler come on, eventually turns off the boiler -
2. right after the main burner goes out, the pilot light is turned off after a loud click.
3. I have to leave it cool a bit, pilot light re-lights perfectly, stays on... until next proper burn cycle terminated by the room thermostat, after which again pilot light gets turned off.
4. Vital clue: the pilot light does NOT get smaller, doesn't choke etc. prior to the click shutting it off for no visible reason ---> so it's not caused by any backdraft or ventilation problem, in which case I would understand safety system doing this.
5. as long as I only give the boiler a short burn, let's say a minute, it doesn't do this... pilot light stays on. I repeated this experiment via the room thermostat many times. But long proper burn cycle leads always to this shutting off of the pilot light after burner is turned off by room thermostat.
So it makes me believe it could be thermocouple? somehow when boiler heats up, it gets confused and then after main burner goes out, it believes also pilot light went out so decides to shut off everything? As my understanding is that the boiler overheat thermostat would only cut main burner, not the pilot light as well
Will be very grateful for any thoughts, it's been driving me and an engineer I consulted up the wall - and it therefore may mean several repeated repair attempts.... My working theory is to change thermocouple via a qualified engineer?