Swimming Pool Heat Pump Overcurrent Device

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eiplanner

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I am experiencing difficulties with a swimming pool heat pump tripping breakers. The name plate on the heat pump says 208/230 volts, 60 Hz, 29 R.L.A., 38 amp minimum circuit ampacity. With an amp meter connected, the compressor kicks on and after starting, registers 30 amps and then begins slowly climbing and ends up at 49 amps after 45 minutes. The manufacturer's tech rep says this is typical. Even though the manufacturer's own material recommends a 40 amp breaker for this device, it is insufficient. It is wired with #8 and will operate fine with a 50 amp breaker. My question is, aren't there any rules or laws governing innacurate name plate data? And, isn't the R.L.A. supposed to be the normal operating amperage of this device? The tech rep says I could put a 70 amp breaker on it if I wanted to. Does the manufacturer not have to be more specific in sizing the overcurrent device or is the 30 amp range they are giving me normal?
 
There should be a max breaker specified on the nameplate. I think the tech is correct in that normally compressors can be protected at up to 2.5 times their RLA. The MCA is the compressor RLA * 1.25 + the fan motor FLA + electronic control amps. I'm not sure what "normal" amps are for a compressor -- depends on ambient temp, pool water temp, charge level, etc.

I'm not surprised that a 40A breaker doesn't hold long term when the MCA is 38 amps -- seems like too close to the edge to me. I would hope the Max Breaker specified on the nameplate is at least 50 amps. It does seem strange though that the amps creep up to over 40.
 
eiplanner said:
I am experiencing difficulties with a swimming pool heat pump tripping breakers. The name plate on the heat pump says 208/230 volts, 60 Hz, 29 R.L.A., 38 amp minimum circuit ampacity.
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This statement is intended to indicate the min ampacity of the circuit which
includes 1.25 x the FLA of the compressor. The actual load of 29 amps should
operate properly under the 40 amps breaker.

With an amp meter connected, the compressor kicks on and after starting, registers 30 amps and then begins slowly climbing and ends up at 49 amps after 45 minutes. The manufacturer's tech rep says this is typical.?
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That sounds like BS. The ratings for the equipment are shown on the name plate and you would be in conflict with the NEC if you exceed the maximum ampacity or breaker size.

Even though the manufacturer's own material recommends a 40 amp breaker for this device, it is insufficient. It is wired with #8 and will operate fine with a 50 amp breaker. The tech rep says I could put a 70 amp breaker on it if I wanted to. Does the manufacturer not have to be more specific in sizing the over current device or is the 30 amp range they are giving me normal?
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You are allowed to install a breaker rating of 1.75 x FLA of the compressor
in some installations but you can not exceed the rating on the nameplate.
1.75 x 29 = 50 amps. The MFG's name plate should show this rating.

suemarkp said:
There should be a max breaker specified on the nameplate. I think the tech is correct in that normally compressors can be protected at up to 2.5 times their RLA. The MCA is the compressor RLA * 1.25 + the fan motor FLA + electronic control amps. I'm not sure what "normal" amps are for a compressor -- depends on ambient temp, pool water temp, charge level, etc.
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440.22A allows the OC device for a compressor to be rated at 175% of the FLA. Under conditions stated, it may
be set at 225%.
 
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I would have to agree too, check the refrigerant side, sure the pressures will affect the operating amps. The RLA is not the operating amps either.
 
The unit is the problem, I looked at a condenser the other day after the havc guy left, and said to get an electrician, unit was doing the same thing starting where it should then climbing. I felt the condenser red hot, felt for air, no air movement. Condenser coil plugged solid. How the @#$ havc tech could not notice this is another thing.
 
Ken9876 said:
How the @#$ havc tech could not notice this is another thing.
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HVAC technicians are no different than electricians. There are real sharp one's, and one's who just want to get home for supper. About 3 weeks ago I was on a call where the AC man told the homeowner to get an electrician for their outdoor condensing unit that was tripping the breaker. When I amprobed it, it was drawing exactly what the dataplate had stamped for the locked rotor current. The compressor was locked up solid. I asked myself at that time also how he could have missed that.
 
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