main 15he heat only explosive ignition

[gasmanrob]

Have you tried the simple stuff remove the burner and vac it the suprimas always end up full of dust. Then remove the can and check the cups are hollow and not smoothed over with dust? An atomiser with some soapy water in it and a 1/2 paintbrush with the handle cut off is usually the best way to clean them. Also if it's a band b dose it have a recuperator on the flue if so the acidity may have caused corrosion and fragments of the heat exchanger may be blocking the flue ways

 

[gasmanrob]

Not having worked on one I don't know what board this has but the band a solo and promax sl had a jumper on the PCB that could be removed for low rate ignition I THINK it was the yellow one