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Topic: Rear furnace blower motor (Read 475 times) previous topic - next topic

Rear furnace blower motor

93 GV rear furnace blower motor doesn't get up to speed and then kicks out the safety switch in the access panel. I took off the motor/squirrel cage cover to make sure there were no obstructions, motor just seems slow, front furnace working fine. I'm guessing I need a new blower motor? could it be the board? Should I upgrade the board anyway since I have it out? Seeking expert advice. Thanks

Re: Rear furnace blower motor

Reply #1 –
Start by checking voltage to the motor.

Also, verify no obstructions to air return or output/vent side.

Re: Rear furnace blower motor

Reply #2 –
Likely the motor is getting hot as well.

Re: Rear furnace blower motor

Reply #3 –
Thanks Brett, I will check those things, another question/problem- we had a Lasko space heater plugged in up front to save propane(we are on shore power 50 amp)  the heater started acting funny, the display was crazy, the remote or the buttons would not work. I unplugged from that outlet, tried another outlet, same problem, brought it in the house and it works fine. My wife read a thread on an RV forum that said everything runs thru the inverter and pulling that kind of load for any length of time would cause problems(damage inverter, burn up wiring) I haven't tried again, just using the furnace now. We're in GA so the cold is manageable, have you heard of this sort of gremlin?

Re: Rear furnace blower motor

Reply #4 –
You need to check the outlet with a VOLTMETER.

And the vast majority of inverters have a "Pass through" feature.  So, when on shore power, they just pass the shore power through.

You are correct-- if the inverter is powering your space heater, it will take the battery down very quickly.

I would also check the CG outlet with your voltmeter just to be safe.

Re: Rear furnace blower motor

Reply #5 –
What's cg outlet?

Re: Rear furnace blower motor

Reply #6 –
Quote from: mikerox –
93 GV rear furnace blower motor doesn't get up to speed and then kicks out the safety switch in the access panel. I took off the motor/squirrel cage cover to make sure there were no obstructions, motor just seems slow,

My rear furnace's blower motor was pretty stiff upon arrival.  You can take the motor out without removing the entire furnace, with just a little finesse.  Remember to mark "Top."  I carefully drilled an 1/8" hole into each bearing doing my best to keep the drill swarf out and soaked the bearing felt with Mobil 1.  A few hundred revolutions with my portable electric drill and everything was spinning freely.  Or while you have the motor in hand you can purchase a new one.

Re: Rear furnace blower motor

Reply #8 –
Why not use a heavy duty extension cord from the "CG" pedestal to your Lasko heater? Bypass everything that is in between the two right now.

Re: Rear furnace blower motor

Reply #9 –
Dry bearings will slow it down.
I don't think it would run at all if you had a board problem related to turning on the blower motor.
Do you have two furnaces?
If you do they probably use the same board. Swap them.

Re: Rear furnace blower motor

Reply #10 –
11.7 v to the motor

Re: Rear furnace blower motor

Reply #11 –
Start tracing from the house battery bank.  See where you are going from house battery voltage (on shore power should be over 13 VDC down to 11.7.

Be sure your terminals on the battery are clean and tight.

Re: Rear furnace blower motor

Reply #12 –
Will have to tackle this later, wife has other plans for me now.

Re: Rear furnace blower motor

Reply #13 –
Oil bearings
 

Re: Rear furnace blower motor

Reply #14 –
I had a similar issue that you are experiencing, and after searching high and low and oiling bearings, I found an enormous muddauber nest deep down in the flame tube. After "jackhammering" it out (those are built to last. Wish other building processes were as tough), works like a charm. I didn't verify voltages, so, you still may have an issue there.....