In the morning when I first fire up the heater, I get a boom. The unit comes on and heats normally and seems to run fine. When it reaches heat setting it shuts off normally. Then when it calls for heat again it ignites smoothly. To me it sounds like a tiny leak that occurs from several hours of no usage, but I have not detected any smell when I put my nose to the floor near the burner tray. There is no fan in this style of furnace. The unit error display doesn't really provide me any clues. Flame strength is 8. voltage is 28 volts. The errors are all CFH/no flame. I don't know if that is caused by how it is shutdown which is done by turning off the pump and causing the water pressure switch to open (original installation by pool builder).
So far here is what has been done:
1. All leaves/debris vacuumed up, top removed and cleaned inside.
2. Fittings around gas valve/pilot tube leak tested with soapy water - all OK
3. Pilot igniter removed, orifice replaced with new propane piece, Pilot tube blown out and inspected.
4. Ground wire removed, all connections cleaned and reinstalled.
5. Control board inspected for any obvious moisture contamination or bad solder joints - nothing found
6 Burner tray completely removed and inspected. All holes clean. Minor rust tapped out. Very little debris
7. All burner jets removed and openings checked with large paper clip. Tube checked for debris/webs - nothing found and no clogged ports.
All this was done over a few days. Same result. Looking for any further suggestions. I suspect an undetectable leak and will put my own fan in front of it at the next attempt. Also, I will tap the valve with a rubber mallet to see if I get any change. I will check the pressure too but since it performs good after initial start, I have my doubts. I'm hoping it is not the board or the valve.
Thanks for any suggestions.
So far here is what has been done:
1. All leaves/debris vacuumed up, top removed and cleaned inside.
2. Fittings around gas valve/pilot tube leak tested with soapy water - all OK
3. Pilot igniter removed, orifice replaced with new propane piece, Pilot tube blown out and inspected.
4. Ground wire removed, all connections cleaned and reinstalled.
5. Control board inspected for any obvious moisture contamination or bad solder joints - nothing found
6 Burner tray completely removed and inspected. All holes clean. Minor rust tapped out. Very little debris
7. All burner jets removed and openings checked with large paper clip. Tube checked for debris/webs - nothing found and no clogged ports.
All this was done over a few days. Same result. Looking for any further suggestions. I suspect an undetectable leak and will put my own fan in front of it at the next attempt. Also, I will tap the valve with a rubber mallet to see if I get any change. I will check the pressure too but since it performs good after initial start, I have my doubts. I'm hoping it is not the board or the valve.
Thanks for any suggestions.