Furnace Blower Question
I apologize if I've asked this before. I searched my old threads and didn't see it. I'm looking to fix this thing this week if possible.
It's a 1984-era Suburban 35k BTU furnace. From a cold start, it will turn on as it should and get the RV up to temp. When it comes time to turn back on, however, the thermostat will click and the fan will run for about half a second and quit. That's it. If I turn the thermostat on and off a few times it will eventually come on and stay on. Then functions as it should until it gets up to temp and does the same thing again.
I noticed that the fan behavior on this one is different than the rear, 18k BTU furnace. That one waits about 15-30 seconds before the fan starts. This front furnace fan comes on immediately. I think the change in fan strategy is because I can see the circuit board in the front one has been replaced - the whole unit has obviously been removed before so there must have been trouble with it.
So - I don't want to start throwing parts at it without some direction, but maybe that's the only course of action. Circuit board first? Or blower fan? Are there diagnostics (blinking lights) on the circuit board in a unit this old that would tell me anything?
It's a 1984-era Suburban 35k BTU furnace. From a cold start, it will turn on as it should and get the RV up to temp. When it comes time to turn back on, however, the thermostat will click and the fan will run for about half a second and quit. That's it. If I turn the thermostat on and off a few times it will eventually come on and stay on. Then functions as it should until it gets up to temp and does the same thing again.
I noticed that the fan behavior on this one is different than the rear, 18k BTU furnace. That one waits about 15-30 seconds before the fan starts. This front furnace fan comes on immediately. I think the change in fan strategy is because I can see the circuit board in the front one has been replaced - the whole unit has obviously been removed before so there must have been trouble with it.
So - I don't want to start throwing parts at it without some direction, but maybe that's the only course of action. Circuit board first? Or blower fan? Are there diagnostics (blinking lights) on the circuit board in a unit this old that would tell me anything?
