Baxi Solo 3 pf 50 excessive hystersis on flow temprature control

[JS]

Hi, My parents have a Baxi Solo 3 PF 50, It will only start to fire when the flow temprature has dropped to about 25 degrees C and then will keep firinging for about 1/2 an hour when the flow temprature reaches

55 degC. The controls are calling for heat and the boiler on neon is lit, the overheat neon is never lit. The fan and other neons do not come on untill the boiler fires. I do notice a clicking sound like a relay when rotating the temprature control on the boiler, but it still doesn't fire. The temprature control is normaly left at max.

Any clues?

Thanks

[geoff]

In message , JS writes

Well, given the fact that you said that you can hear a relay clicking in, then the comparator on the pcb is sensing the sensor / control resistance. The pot is unlikely to be faulty, the temperature sensor could be (should be 100k at 20 degrees, and about 30k when at temperature), or it could be the pcb

not the best time of night to be answering ...

I'll sleep on it