Heat Pump Amp Draw Question
My first post here, thanks in advance for any help. My wife and I are in the inspection stage of a 5 year old house in Phoenix, and I'm not sure how to read the amperage draw from the name plate. They are both Aire-Flo AFHEAT12B-36 units, 1 for each floor.
I did very basic tests in AC mode, checking compressor amps after running them for 30 minutes and measuring the return and supply air temp differentials. Both seem good - 11 to 12 amps and 15 degrees F differential. The nameplate shows 17.9 RLA and 90 LRA.
My question has to do with heat mode. At start up, amps on both units were about 12, and steadily climbed to 21 amps within 10 minutes. One unit reached 23 amps in 5 additional minutes, then dropped to 0 with a quiet hiss from the compressor which continued to run for about another 5 minutes at (I assume) no load. The other unit ran at 21 amps until I shut it off at the thermostat. I shut down the 23 amp unit, left it for 1/2 hour and repeated the test with the same result. Both units delivered plenty of heat into the house while the compressors were running.
I'm not familiar at all with heat pumps, but 21 to 23 amps on a 17.9 amp system doesn't seem right. The thermostat was still calling for heat (I set it to 80) when the compressor cut out. If anyone can confirm this is likely a defective unit, I'll call in a tech to run proper tests, but I'd like to at least throw it out to you experts for an opinion.
Thanks again for any suggestions.