Need help with a SF 30 Suburban Furnace
My original problem was the usual story. The fan would come on and the furnace would fail to light and the fan would then shut down. I, standing outside could hear the switch and smell gas but the spa...
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No gas.
It seemed that most of the many posts about Suburban furnaces claimed the same problem as I had. The fan came on and I couldn't hear the igniter sparking above the fan noise. I could smell no gas on the outside. Most every bit of information I read said and the circuit diagram showed that the over temperature thermostat and the sail switch were usually the culprits. I removed the furnace from the housing and set it up on a bench, running it with a 12v battery. The spark looked good but, of course, there was no gas. Everything looked good so I reinstalled it and it was just like before. No gas. I let two wires touch and then nothing worked, no fan, no nothing. I found the glass fuse in the thermostat and I was back to the original situation; fan ran, no heat. I took a chance that it must be the thermostat so I bought a new one identical to the OEM and everything works. End of story. I don't really know what was wrong with the thermostat and don't care. It works.
I had a previous problem with this furnace about 3 years ago. Found, what felt like, a 1/4 lb dirt dabber nest in the duct. Put screens on the outside to prevent this from happening again.
It seemed that most of the many posts about Suburban furnaces claimed the same problem as I had. The fan came on and I couldn't hear the igniter sparking above the fan noise. I could smell no gas on the outside. Most every bit of information I read said and the circuit diagram showed that the over temperature thermostat and the sail switch were usually the culprits. I removed the furnace from the housing and set it up on a bench, running it with a 12v battery. The spark looked good but, of course, there was no gas. Everything looked good so I reinstalled it and it was just like before. No gas. I let two wires touch and then nothing worked, no fan, no nothing. I found the glass fuse in the thermostat and I was back to the original situation; fan ran, no heat. I took a chance that it must be the thermostat so I bought a new one identical to the OEM and everything works. End of story. I don't really know what was wrong with the thermostat and don't care. It works.
I had a previous problem with this furnace about 3 years ago. Found, what felt like, a 1/4 lb dirt dabber nest in the duct. Put screens on the outside to prevent this from happening again.
