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. It appears to take time 5-10 minutes for the main burner to restart even after the pilot is relit. It does it in the high and low thermostat position. Would you know what item needs to be replaced? My servicing agent has been no help and charged me 135 pounds for nothing.