package heat pump not working, but tested ok

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Old 07-01-12, 10:18 PM
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package heat pump not working, but tested ok

So I've got a package heat pump, been working fine with no issues until saturday afternoon. Everything was running but no longer making cold air. I turned the unit off and called a tech. It took about 30-40 minutes for the tech to get here, at which point we turned the unit on and it worked fine. He tested pressures, temps, etc and everything was fine.

Today, again it stops cooling while I am at work, so I tell the wife to just turn it off. When I get home I turn it on again and again it works. For a little while.
I go outside, blower is running, compressor and fan aren't. I turn it off, wait, turn it back on, only this time only the blower is running.

Before I call a tech out again, any ideas what might the issue be? Remember, when it was running correctly everything checked perfect.
 
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Old 07-02-12, 07:39 PM
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while it is in a failed condition dont touch anything and call a tech.
 
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Old 07-04-12, 09:25 AM
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It's still acting up. Monday when I turned it on, this time the condenser fan didn't come on. I beat on it and it slowly spun up. Seems to me that would be bearings going bad. I put a few drops of oil on the end I could access without taking things apart and it seems to help but..

The fan will just stop running for no apparent reason while the unit is cooling. Now, it might run for an hour before it stops but I notice it's not cooling, go outside, everything is running but the condenser fan.

I don't know if there is some kind of thermal self-resetting breaker on the fan motor, but it sure seems like that's the problem. So... I'm going to get a new fan motor, since it's apparent the bearings are going out on it and see if that solves things.
 
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Old 07-04-12, 09:51 AM
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The new motor will probably require a different capacitor.
Order a new cap with the motor.
If the fan spins freely with power removed, the cap may be the only problem.

It would have been great if your tech listed the running amps and the rated amps of the compressor and fan as well as the capacitor readings on his invoice.
 
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Old 07-04-12, 03:58 PM
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So, just some more testing and updates.
I get about half an hour of run time, and the condenser fan stops.

I thought caps only worked or didn't, you sound as though there's a middle ground?

I'm not entirely convinced anymore than it's the fan motor anymore, given that I get about half an hour of time (or longer) before it stops. Remember it's just the condenser fan, the blower and compressor continue to run. If I didn't step in and turn it off, not sure what would happen (beyond maybe burning out the compressor).
 
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Old 07-07-12, 06:28 AM
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As the capacitor reading drops from its original reading the amperage will increase.
I have measured 5 microfarad capacitors at 3 and the motor ran for me but it failed to run the previous night for the homeowner.



I have measured 50 microfarad compressor capacitors at 30 when a hard start kit is in use. The compressor ran but it was pulling more amps the the RLA rating on the unit nomenclature.
 
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Old 07-07-12, 12:03 PM
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I did a little more checking on wednesday. I turned the unit on, waited about 20m then went outside and waited. Sure enough, around 25-30m the condenser fan literally ground to a halt. I started removing it and within 5 minutes the motor was so hot I couldn't touch it anymore.

I bought a new motor and cap (new motor used a different one) for $155 locally and installed them last night. So far the a/c has been working great. I'm getting 59f air out of one of the farthest vents which probably isn't bad given it's about 95 outside.

Thanks for everyones help. Just wish I hadn't spent $75 on a service call to end up diagnosing it myself.
 
 

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