Main burner c&m britony

[kevoffthetee]

I'm after a little advice about my c&m boiler. The heating works and the radiators get hot, but not very quick and only the stage one burner is running. The hot water is non existent until the tap is set to trickle.

After taking the front off the boiler I've noticed the main/full burner isn't kicking in most of the time. When it does the water is hot as it should be and the rads heat up quickly

Given that is does work at times, can I rule out the pcb? After working with computers for many years my understanding is that various functions either work or they don't, there is no intermittent on a circuit board. I replaced the dhw thermistor a few months back so have experimented by swapping it with the ch thermistor to see if it improves the ch but no luck.

I'm getting a multimeter from work to test the voltage across the wiring on the gas valve solenoid in case of a sticky valve or dud solenoid

Thanks, Kev

 

[kevoffthetee]

Will also add there has been a new heat exchanger fitted last week, thanks

 

[ianmcd]

Please replace the combustion chamber and get a RGI in to sort this you are putting yourself in danger and breaking the law by doing this

 

[kevoffthetee]

Thanks Ian, if that that's the next step then that's what I'll do.

I've never had any intention of tampering with anything other than simple valve, I'm not daft enough to open the main burner section at the top.

 

[kevoffthetee]

I've read the OP again and think I might have alarmed you regarding the removal of the cover. It was the white front cover and not the chassis cover.

The only thing I've replaced is the secondary heat exchanger, dhw thermistor and control pcb

 

[kevoffthetee]

I have a heating engineer coming this afternoon at 3.30 to take a look. I'm suspecting he is going to say its the pcb rather than the combustion chamber as I've taken Multimeter reading of the wires going into the gas valve.

The wire to the 1/3 valve has a reading of 23.4v, the 2/3 valve reads 0v and the security valve reads 23.3v

Please correct me if wrong, I'm just trying to get a ball park cost so I know why to expect when they come

Thanks

Kevin