2 compressor heat pump

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hvac novice
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2 compressor heat pump

Post by hvac novice » Fri Aug 03, 2012 9:53 pm

I'll give as much info as I can. I work at a resort where I sometimes work on ac's. They asked me today to check-out the system at the Front Desk. Man,was I lost! Didn't really know what to do. The first stage compressor was making considerably more noise than the other compressor was making. The second compressor was sweating real good where the first stage wasn't even cool.The system was located in the attic and the label had FHP Manufacturing Division HE140-3HZC on it.There's a water tower nearby this building that I think is a part of the system and it's info - Aircoil Co. M#VF1-036-51L. I want to learn what I can about it so I won't be in the dark. Hooked gauges up to second stage and pressures -=91-lbs. * lbs. First stage compressor -=55-lbs. and * lbs. It was approx. 92 degrees outside and the vent temperature was 68 degrees at best. I added freon to first stage to get it closer to second stage readings. Got it close,but that didn't do any good. Can someone help me out by first telling me the theory on how this system is supposed to work and then maybe give some ideas on what could be wrong with this one?

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- 2 compressor heat pump

Post by danorano » Thu Apr 04, 2013 8:03 pm

Whats with all the asterix (*) in the messages? It kinda makes the threads unreadable...

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- 2 compressor heat pump

Post by Freon » Fri Apr 05, 2013 10:36 am

First, when you post do not use dashes, slashes or question marks. Due to spammers these get turned into an *. Simple sentences with letters, numbers and spaces work fine.

Post your pressures again. It seems the second compressor is doing all the work. Usually the first compressor, stage 1, will run and if it can not keep the temperature within 2 degrees of the thermostat set temperature, the second compressor will start. You need to focus on why the first stage compressor system, including the evaporator, is not doing its job. Use the manufacturer's data sheet, usually in the electrical compartment of the compressor, to see what your pressures should be.

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