Baxi 35/60 won't fire up

[omo]

Could somebody explain what this fault could be with my Baxi 35/60. On initial start up the boiler works perfectly but on reaching the required temp ~70-80 deg C it shuts down on both flame failure and Safety thermostat faults.The pump continues to run on for a few mins but when the temperature in the house reduces the boiler won't start up again and I have to reset it manually.

[ "bold" turned off by Mod]

 

[ChrisR]

Faulty stat or lack of circulation due to tired pump or blockages in circuit.

 

[omo]

Hi Chris, I did change the safety thermostat recently so would you reckon that I should flush out the system now and/or change the pump at this stage.
Mike

 

[gas4you]

Have you checked the boiler stat is working correctly? It may be knackered and leaving boiler to shut off on overheat only.

 

[omo]

Could you tell me where the Boiler stat is positioned. I can't see where it is on the schematics. Also what readings should I be expecting to see if it is/not functioning.
Thanks.

 

[omo]

At last I have found what was wrong with baxi 35/60. One of the 2 blue wires coming back to the pcb from the over temperture heat stat was intermittently going open circuit. So hard to find this out and was jammy to find it in the end. Having replaced this stat when the fault occurred initially,then changing the temperature sensor and then checking that the pump was working properly I was still getting the fault. Yesterday I was testing pressure on the outlet of the gas valve waiting to see what would happen the pressure(6mbar) when the fault would occur. Of course the fault still didn't occur after 2 hours of the boiler running (normally would happen within 15 mins).So decided to quit yet again and as I was hinging the control facia back into position the boiler shut down on an over temperature fault.It was then on closer inspection of the PCB and moving the wires i was able to recreate the fault.
No more getting up at 2 in the morning to reset boilers!