Hi recently had glowworm problems, F19 & F5 faults, loss of water pressure & no DHW. Engineer been and
replaced plate to plate exchanger, reset overheat switch, replaced PRV and flexi pipe(blocked).
Boiler works, radiators get warm (display reads 31Cmax) and hot water gets hot(for about 20 seconds) BUT burners wont stay lit.
Every 40 seconds or so the burners turn off for about 20 seconds and then come back on again. Does this mean some sort of temp stat is now playing up , gas fault ?