Hi . check they have fitted a sealed system kit in the boiler, if the heating is now pressurised .
I can do that but, as I said, the problem existed before the pressurised system was fitted?
Hi , was the PCB ever replaced?
Yes, very early on when the boiler was first fitted.
It may be that PCB wasn't changed to the new one. It took ages for potterton to admit a manufacturing fault with them . they get hot and crack a circuit track. The new ones have a bit of protection from heat as the board sits against the boiler.
OK Will ask for those to be checked. The Manual talks about "intermittent Lockout" and lists possible causes. One references " ... if APS fails to operate .." So, last question/s: what is APS and is intermittent lockout what I'm experiencing??
That's the air pressure switch. The fan has to be running for the boiler to work safely. The APS senses the fan is running. If they APS goes faulty the boiler will lock out . cheap and easy to fit