I just replaced my furnace blower motor and now I?m having issues with it running correctly for a bit and then it starts just blowing cold air and won?t cycle off. When I turn it off at the thermostat and wait a bit to switch it back on, it will blow warm for a while and then does the same thing. Where to start????? Thanks!
Furnace not always blowing hot air
- Thread starter DH1644
- Start date
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Utclmjmpr
Well-known member
Double check the "Gang" plug at the furnace,, I had a similar problem and found the plug not fully inserted.>>>Dan
Gary RV_Wizard
Site Team
The only way it can blow cool air is the burner goes out. That's not a motor issue, so you must have messed up something when doing the swap. Possibilities are anything that interferes with the combustion air intake or exhaust output, the Hi-Limit switch, burner is overheating, or gas pressure drops too low. One place I would look right away is the gasket that separates the circulation air path from the combustion/exhaust path. If air leaks between the two, it often interferes with combustion, plus it is potentially dangerous (exhaust fumes get inside the RV).
Take a look at my Furnace Troubleshooting Guide in the forum library at http://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf
Take a look at my Furnace Troubleshooting Guide in the forum library at http://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf
Gary RV_Wizard said:
I've read this guide, and I'm still stumped. I have a 2019 Aerolite with a Dometic/Atwood furnace. The blower starts up great but I have to repeatedly go out and reset it at the motor reset because it won't fire up. Resetting the thermostat inside doesn't work, and it's not a gas issue. Not sure where to start, resetting outside gets it to fire on eventually and run fine.
Well, it could be a gas issue, but I changed the tanks and ran the inside burners, there is nothing downstream of it as it's the furthest propane use appliance from the tanks. The blower comes on for 6-10 seconds and then just shuts off. Last night there were blinking lights on the control board, resetting it immediately got heat going.
Gary RV_Wizard
Site Team
"Won't fire up" means the burner doesn't ignite? But after you wait awhile and use the external Reset, it does light and heat ok?
If the burner shuts down while heating but the fan continues to run, the issue is almost surely that the High Temperature Limit was exceeded. The burner is shut down but the fan continues to run to cool the furnace. Most often this is a result of blocked air distribution ducts, blocked furnace return-air intake, or simply poor design of the distribution ducting. If the fans can't move enough circulation air across the heat exchanger, the furnace gets overheated and the Hi-Limit switch shuts the burner off.
If the burner shuts down while heating but the fan continues to run, the issue is almost surely that the High Temperature Limit was exceeded. The burner is shut down but the fan continues to run to cool the furnace. Most often this is a result of blocked air distribution ducts, blocked furnace return-air intake, or simply poor design of the distribution ducting. If the fans can't move enough circulation air across the heat exchanger, the furnace gets overheated and the Hi-Limit switch shuts the burner off.
Lou Schneider
Site Team
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- Mar 14, 2005
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Make sure the squirrel cage blowers are rotating in the correct direction. They should rotate so the impellers are turning in the direction of the output airflow. If you reversed the motor connections and they're turning backwards they'll still blow air, just not as much.
Insufficient airflow can make the furnace overheat and trip the overtemp switch. Like Gary said, this shuts down the burner but not the fan, which continues blowing until the thermostat temperature is satisfied or you turn the thermost off and then back on.
Not enough airflow can also keep the fan sail from engaging, which will cause the aborted start-up.
Insufficient airflow can make the furnace overheat and trip the overtemp switch. Like Gary said, this shuts down the burner but not the fan, which continues blowing until the thermostat temperature is satisfied or you turn the thermost off and then back on.
Not enough airflow can also keep the fan sail from engaging, which will cause the aborted start-up.
