Just replaced fan motor and capacitor worked for 30 min now no go, need help!

Faztaz

I just spent the last 6 hours trying to problem shoot my HVAC and now Im at wits end.

Its an older (1972) 5 ton GE unit. The condenser will turn on but the fan motor wouldn't so purchased a new motor and capacitor installed the two. The unit worked perfectly for 30 minutes then the fan started to slow down and then completely stopped. Now the condenser will turn on and make some weird noises. I turn it off after 2 minutes or so in fear of it overheating. The fan will not turn on at all. I tried to jump it by spinning it myself but no go. The capacitor doesn't appear to be blown. Any suggestions? There are 3 additional capacitors and a fuse box all connected to the condenser. these all appear to be intact.

bob22

Contactor might be bad?

Marty S.

Compare the new motor to the old. Same HP,amp draw and RPM ?

beenthere

Also compare it to what the data tag says the motor should be.


Any chance that the fan blade was changed sometime recently?

Faztaz

Yeah the motors are the same (ie Amps, H/P, RPM)
I actually jusy switched the blade from the old motor to the new motor.

I was inspecting the unit closely and noticed the insulation on one of the motor wires going to the capacitor was burnt and there were frayed wires. I think it was resting on the hot condenser when I buttoned everything up. I spliced the wire to remove the frayed end but still no go. Do you think the capacitor could have been damaged?

Yoyizit

Sounds like you haven't found the root cause of the first motor failure, but the only reason external to the motor/cap that I can think of for this would be low voltage due to bad HVAC connections or a bad connection in your house wiring.

For contactors/relays at rated current, less than 30 mV across closed contacts is good, more than 100 mV is bad.

beenthere

Its possible the cap over loaded from being shorted out.

hvaclover

That GE is old. It uses a small mfd cap in series with the run cap to provide off cycle trickle voltage to keep the compresor rump warm.

Check the entire capacitor circuit for othe possible problems.

__________________
Just slow, not stupid.

yuri

Only a "mature" tech like yourself would remember that one.

I will leave the rump size joke for later.

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"Cut it twice and it is still too short".
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