Baxi Solo 60/4 RS, Pilot Light will not stay on.

[Freewheel1]

Help please.
I wonder if someone can help with my boilder in terms of fault finding.

This monring no heating or hot water overheat has tripped popped it back and tried to relight the boiler.
Note; The bolier has always tripped out on overheat apprx once a month to 3 months, i have had it serviced and it always does the same.

With the pilot not lighting. I looked in the manual and if the pilot fails to stay alight either the overheat cut out has tripped or the Thermocouple has failed.

Despite my thoughts that the thermocouple was ok i changed it. I was right it was ok, Still the same. I'm not sure what wrong?

Just so you are sure, the pilot lights then goes out, release the gas button and flame goes out.
Important; i can hear the solenoid clicking so i'm pretty sure that is working.
I spoke with Baxi briefly today and the guy advised that it could be the Thermostat overheat, but again don't want to buy a part without knowing this is correct.

i remember in the past replacing the controller (Honeywell st6400) when it seemed that the boiler was at fault.

Many thanks for any response.

 

[45yearsagasman]

Without being in front of the boiler its not easy to diagnose.A tripping overheat suggests a boiler stat/pump overrun fault.The flow temperatures need to be measured to prove accuracy of the stat.From memory the thermocouple has an interrupter block connected to the overheat and all these parts need to be checked.A good boiler repair man should sort that in a very short time.Parts are not expensive.

 

[Freewheel1]

many thanks for your reply.
for ref. The overheat is not tripping at present
The overheat cut-out is pressed in and stays so.

i have a meter, any way to check if the bolier stat is faulty. The guy at baxi said check for contintuity i'm guessing he means check across the two spade connectors...take a breath. i'm not sure he's actually right on this?

 

[45yearsagasman]

Is the boiler working at present or can't you get the pilot to stay on?

 

[Freewheel1]

At the moment the boiler is not working

 

[45yearsagasman]

If the overheat is ok and you have fitted a new thermocouple then you need to suspect gas related faults such as pilot,gas valve etc and for this a RGI should investigate.A multimeter is required to measure thermocouple outputs etc.

 

[Freewheel1]

i switched it all off last night. Tried it this morning and all working.
i'm puzzled at a higher level......

only two wires from the controller to the boiler (to power the solenoid, switch it on i guess). I could hear the solenoid switching yesterday so i knew that was ok.