Rheem furnace blower issue

[gary]

Rheem Furnace

Model RGDA-075A-AR

SN CN3D108 M1085 1844

Yesterday morning I woke to a cold house.  The burners were working, but the blower wasn't.  I thought I could hear a hum coming from the motor.  I went ahead and pulled the motor and took it to a place in town.  They tested the motor and said it was fine (connected leads to the wires and plugged it in).  They also said it didn't require a starting capacitor.  I reinstalled it and it was working fine.  Next morning it stopped again.  I banged on the blower housing and the motor started spinning after I put the cover back on.  I don't know if the banging actually did anything or it was just coincidental.  The blower has been working fine all day.  Ideas?

[hvacdrd]

If it fails to work again check voltage at the motor leads. You should have 120VAC, if you do and the motor isn't running then it is a bad motor. Carefully reach in an spin the wheel by hand & power up to see if it takes off.

If you have no power to the motor when it should be running then it is time to trace out the circuit. We will need some idea of a wiring diagram since Rheem doesn't give access to their site without being a Rheem dealer.

[FREONBOB]

you have a bad motor , you have a dry or worn bushing in the motor that will not let the small hp motor get going    if you need more help send your mod# and ser#  and i will look anything up you want     we are a RUDD/RHEEM/ CORSAIRE/ YORK  dealer    just dont expect me to send you anything this way(e mail- this forum ) i am new to the web and not that good at it yet 

[gary]

Thanks for the replies and suggestions on how to proceed.  It has been working OK since yesterday morning.  I'm inclined to just let it ride for the time being.  Ten years ago I had the motor rebuilt (It was squeeking real bad).  When the time comes, should I get it rebuilt again or just buy a new one?

[bobbyghvac]

You ought to think about getting a new furnace. It's obviously quite old.

 

[gary]

Yes, it is old.  Circa 1986 I believe.  I (still) need to get the fan motor rebuilt or replaced, but if it is operating fine otherwise, is there value in replacing the entire unit?  Will a modern unit be so much more energy efficient that I'll actually see a pay back in a reasonable amount of time?

[bobbyghvac]

If you are going to stay in the house for a long time you would save money in the long run. Also, have you ever had the heat exchanger tested. Older Rheem's were notorious for the heat exchanger cracking (obviously not the problem you are dealing with right now).

[gary]

I had a furnace check up about four years ago, so I guess I'm due to have a pro check it out.  I actually have been thinking about the possibility I'll need, or at least should get, a new furnace in the near future.  I have no idea how long I'll be in this house.  This house has ~1500 SF of living space.  What is the ballpark amount I'd be looking at for a new furnace.  Nothing extreme, just a typical replacement.

[Cactus Bob]

PLEASE , PLEASE , PLEASE  KEEP YOUR OLD FURNANCE AS LONG AS YOU CAN .!!!!! and in joy the fact you have a SIMPLE furnance  . easy to work on and cheep to fix  .  new MODERN  heating systems  can be a  $$$$$ NIGHTMARE $$$$$$  with lots of downtime  waiting for parts    you might save a little on fuel but you will make that up on repars and then some