Joe Harper
07-30-2009, 10:53 PM
I get a call for a WIF only holding 20 degrees. I get to the site and look at the condensor. Older Techumseh condensing unit, bristol compressor (3hp) mated to bohn evap. The first thing I notice is the rusted 405 drier, but protecting this is a 053 drier:eek:. The output of the 053 is just about to sweat, dew point was about 73, ambient of 96. The compressor is marked "409" on top. I was almost out so I went to the shop and picked up a fresh can. I get back and compressor was off on thermal. I cooled it off and still wouldnt start. Found bad run and start cap. I put on a new start relay for good measure. I pump down the system (what already wasnt sitting in the condensor). It ran about 30 seconds and hit the bypass. I get the yellow dog and pull out 3 lbs. Cut the driers out, the 053 had come apart and most of the innards fell out on the concrete. At least the other drier was there. I put a 163 in and vacuum the system. Lots of moisture came out, as it took 1:15 to bring the low side of the system to 500 micons. I fire the system up and watch the pressures. After 10 mins I had 195/45. 105* on liquid line, 50* on suction. I decide to check and see if the fans kicked on early or what else was going on.
No fan action, no frost on anything. I hear the refrigerant hissing through the txv. I opened up the valve untill the hissing stopped. Go back and check pressures. 180/35, 37* suction temp. Upon the discovery of the negative superheat numbers:D, I go and talk to the maintenance man,(this is a hotel). He tells me that he doesnt mess with it much, he did find a leak at the flare fittings on the receiver and drier. He tightened the nuts, the chief engineer is the one who filled it back up. He shows me the empty can of 409 in the storage room. Its empty, not even residual is left in the can. I wait another 1/2 hour to see if the box pulls down. Box is at 30 after 1 1/2 hours of run time. It started at 40. I run a pumpdown test. It gets to 10", although a little slow after 5 psi. I tell mgmt to call in the morning if box. Next morning box is at 20*. 180/25 27* suc temp. I pull another pump down test and the compressor cant get below 10 psi.
Any guesses? The answer is disturbing....
No fan action, no frost on anything. I hear the refrigerant hissing through the txv. I opened up the valve untill the hissing stopped. Go back and check pressures. 180/35, 37* suction temp. Upon the discovery of the negative superheat numbers:D, I go and talk to the maintenance man,(this is a hotel). He tells me that he doesnt mess with it much, he did find a leak at the flare fittings on the receiver and drier. He tightened the nuts, the chief engineer is the one who filled it back up. He shows me the empty can of 409 in the storage room. Its empty, not even residual is left in the can. I wait another 1/2 hour to see if the box pulls down. Box is at 30 after 1 1/2 hours of run time. It started at 40. I run a pumpdown test. It gets to 10", although a little slow after 5 psi. I tell mgmt to call in the morning if box. Next morning box is at 20*. 180/25 27* suc temp. I pull another pump down test and the compressor cant get below 10 psi.
Any guesses? The answer is disturbing....