Thanks everyone. Bought a kane 455 flue gas analyser. Set the gas valve now all good. Was running too lean on minimum hence cut out and cycled. Boiler as good as new. Anyone want to buy a calibrated analyser?
I have a bosch greenstar 30 si which keeps cycling every 30 seconds only on ch. All rads get warm but not hot 14 in total. The pressure in the system holds about 1.7 bar .The system has been flushed all thermostatic valves work and are fully open. I have checked the pump it's fine. I have...