View Full Version : Macquay heat pump dilema
01-19-2006, 04:00 PM
I am working on a Macquay wshp r-22.In cooling 57#-32* high 205#-102* water in 70* water out 78*.heating low 55#-30* high 275#-123* water in 70* water out 64*. The head pressure in heating and return gas temp. at 60* is going to kill the compressor,it really gets hot in heating. It's a CCH019 about 11/2 ton,with a rotary compressor and cap tubes. Any thoughts on this would be appreiated thanks.
01-19-2006, 05:40 PM
I had one of these hide aways about a month ago 1 1/2 ton tripping off on high head in heat mode.checked filter and coil ok.Removed charge and weighted in cause people like to juice up things.Still the same issue the real problem was the blower fan motor turning to slow, hard to pick up on such a small unit.
01-19-2006, 08:08 PM
Yeah I would tend to lean toward airflow here also taking into consideration the low evap temp during cooling.
Funny I ripped one of these exact units apart today. Gotta change the "matsu****ty" compressor, horrible burnout. Apparently it now gets replaced with a bristol compressor. Gee thanks for the help Mcquay, I appreciate the estimated one week delivery as well.
01-19-2006, 08:24 PM
The one I had the fan discharge was 90° from the evap.Motor removal from blower housing was on evap side so I had to remove the duct pop the top and remove the blower housing.
01-19-2006, 08:31 PM
This sounds just peachy we just got the contract for a building with around 200 of these units!!! LOL Im gonna kill myself.
01-19-2006, 10:04 PM
Is it an open ceiling,we service an office building with mcquay wshp's and open ceilings.The high return air temps in htg kill the compressors,ceiling fans help.
01-19-2006, 10:10 PM
I think with that head psi in htg you must have either overcharge (easy to do),air (non-cond) or high return-air temps--if your airflow is ok.
01-19-2006, 11:04 PM
Just repl.d three of these monday. One had a bad Comp.(locked up), one had a creeping amp draw, (slight acidic,suspect copper plated cyl. wall-a recip.)one had a bad tube in tube heat ex...I was wondering how all the "AIR" was getting in the glycol-Dummy me 'til I got out the leak detector- it was refrigerant.
The charge is critical on these machines, maybe recovering, then weighing in exact charge would be a big help in your troubleshooting, and may even clear up everything. They run these at 78 F. inlet water year round-do you think 70 might be better for my app. as well?
01-20-2006, 08:18 AM
looks like your water in and out are very close together, could slow that down and see if your temp to your compressor decreases, its like you have too much load on your evap in the heating mode and you cant get the super heat you are looking for. should see at least ten degres in and out. those little rotary comp. run hot.
01-20-2006, 09:45 PM
McQuays arent even worth working on. I have a building with aprox. 52 WSHP. I dont know how many times Ive called for parts and am told that it is obselete.
I have quite a few that run hot like your describing.
But my units are 20 years old. I am just waiting for them to crap out so I can replace them with Tranes, which is more practical to work on, and to get parts for.
01-20-2006, 09:47 PM
Thanks a lot for your replies,great info. Double and triple checked everything. Purrs like a kitten in cooling still high head in heating. My suspition from seeing caps entering bottom of evap. I feel thiers a possibility of dirt in bottom of evap. plugging in heating & blowing clear in cooling.Just my thoughts. By the way pulled from job to check motor center in another building fans not running, found voltage imbalance.Opened HOA pulled bucket wires on top fried blew 400 amp fuse in switch gear, motors running on single phase. Know of one to replace but thats monday, Thanks again guy's.
01-21-2006, 01:28 PM
Is it possable the metering device used in heat mode has problems? The metering device for cooling is ok. I agree with weighing in the r22 and looking at water flow. Should be 10deg diff.in and out. Of course airflow accross the coil is the first thing to confirm. If airflow and waterflow check ok it must be refrig flow problem.
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