I have a Micron 50 ff wall hung boiler glowworm make.. recently i had a new pcb and thermistor fitted .now the boiler when is called to heat by an exterior clock timer [the only exterior control for this boiler]will call the pump to run immediatly for rughly 3 seconds then fan will run and click noise for rughly 5 seconds then it will lock out and immeditaly startup again and run continusally untill temp is reached and it will them stop and start again as normal till the clock ends that cycle and it stops .. question .is this a feature of the new pcb and thermistor or do i have a problem waiting to happen soon ..any suggestion are appreciated ant thanks you in advance mark.