On my Myson Apollo 30/50 when the main burner turns off the unit clicks and the pilots goes out as well this is in both the high and low thermostat setting. Does it always in high thermostat position rarely in low. would you know what item needs to be replaced? My servicing agent has been no help.

ACE PA, January 2009

95% its the thermocouple you need one with an interupter connection ... this has to be your own boiler for you to legally work on it ..get the part from heat and replacement parts if they let you have one otherwise a local company might sell you one

fillippo (retired heating engineer), January 2009