Cylinder Tank - Does this sound right ?

[johnny_t]

I have a BG branded Worcester 430/i boiler, fitted about 13 or so years ago. Lately I have been having a lot of trouble with flame failure errors.

It is just set to Water Heating at the moment, and I have observed that it always seems to be failing when the tank is actually pretty hot, so I came up with the idea that the problem would be the tank thermostat (and then the hot water demand not turning off, and everything getting too hot)

However, when I took the tank thermostat off, I found that the wire to the thermostat had been cut off. To the end of the cable from the boiler was wired what I believe to be a thermistor. A bit like this - https://buyplumbingonline.co.uk/firebird-boiler-tank-thermistor-cable-combi-pcb-acc000wtp.html - but with the end being plastic coated. Also, it seems to be just twisted and taped, rather than connected any other way.

For the moment, I have just wedged the thermistor behind the old thermostat, as I guess it needs to be in pretty close contact with the cylinder, but does that sound right ? No flame failures since, but I just wanted to check I wasn't making things worse somehow.

 

[muggles]

What error code(s) are you getting?

I suspect you're barking up the wrong tree to a certain extent, but you may also be on to something. My immediate thought, if it is flame failure, is a gas valve issue when the boiler is in low fire, but you need a Gas Safe engineer to test that

 

[johnny_t]

I'm getting an EA

If I understand you correctly (just to get it clear in my head) you are saying that when the tank gets near heat, it turns the gas down, but not enough gas is getting through then so that it is failing ? That kind of makes sense, as I do always have hot water, but just need to reset everything a couple of times a day.