(gas) back boiler doesn't come on for CH or HW

[Bunnyman]

He will be gone now steel he always legs it when the pros are around lol

 

[Steelmasons]

Not sure why he constantly leaves himself open for criticism Bunny?....possibly hoping that one day he'll get it right...

 

[ron56]

just an update for anyone interested. Came down south last night. Boiler not working due to no boiler pilot light. Went through the procedure (Baxi 552)..and the pilot light lit, stayed on when grey "button" was released, and fired up to heat the house/hw (we seem to back to cooler weather again!). The boiler has been running normally for 2 hours.

I had suspected a dodgy thermocouple and the guy who used to service the boiler never got back to me so I'll have to find another qualified engineer that is content/competent to service these old boilers.

I guess the pilot light could go out again..if it did I'd still suspect the thermocouple as everything else in the system ,which is pretty simple, seems fine (i.e. 3-way valve, room stat, pump). Anyway I'm here for 2 weeks so have time to see if it (boiler pilot going out) was just a one-off?

What could cause a pilot light to fail/go out like that?? I can never remember it happening before..over many many years. Could a thermocouple work intermittently?

In my experience (which is limited to a propane-fuelled "woodstove") when I twice had a pilot light issue due to a dodgy thermocouple it just failed..dead..nothing...there was no in between "sometimes it works/sometimes it doesn't" stage. I changed those thermocouples which lasted many years each but I won't attempt that on this mains gas boiler.

However, does anyone know if I can get a Honeywell Thermocouple-Honeywell Q.309A 2721- Manufacturer's Part no. 102005 online?

Thanks for reading

 

[DP]

Thermocouple produces a voltage when tip heated. This voltage keeps the gas valve primed and pilot flame to light the burner when next section in gas valve opens to demand on boiler

Thermocouples wears out. You could have insufficient voltage that drops out the gas valve, dirty pilot that fails to heat the thermocouple adequately so intermittent operation. Faulty gas valve can also pop the pilot

 

[Steelmasons]

I'm sure the RGI who attends will have a TC as van stock..
Why do I get the impression you are going to fit it yourself??

Good luck..

 

[ron56]

DP thanks.
Steelmasons..no I wouldn't work on someone's house/boiler unless it was an absolutely desperate situation..and it isn't. I have little or no experience with gas except that propane "wood-stove" I spoke off where over 20 years I've swapped out 2 or 3 TCs. I live in an area with no gas supply so have 30 odd years experience of maintaining oil-fired boilers (well one believe it or not..a Mistral...excellent bit of kit it's been). Never had an engineer in for that and it has worked very well.) But mains gas is not something I feel very confident with so I won't meddle and will leave it to RGI. (are most RGIs happy to work on these Baxi BBs?)

No re the online purchase I just thought that maybe the TC was a bit rare being so old and it might be handy to have one..just in case the RGI didn't have one and time was tight.