Overheat thermostat kicks in Otford, Sevenoaks

A customer in Otford, Sevenoaks, had an external combi oil boiler that was not firing up, or even attempting to fire up.

I put all programmers and thermostats calling for the boiler to fire but nothing happened. I traced the electrics from the source along to where the electrics stopped and found that the overheat stat on the boiler had tripped, causing no electrics to get to the burner.

Once reset the boiler refired and continued to work. Customer had reported that he had to repressurise the system the day before, meaning that with low pressure the boiler got too hot and tripped the overheat stat.