Hallo everyone.(caution ,its a long one.)
One of my boss`s costumers referred us to another deli.My boss handed me a condensing unit about two weeks ago,with the address hour and a half away from shop.
Before I go on let me give the specifics:
Box;8 feet long,Kysor\Warren,mn;539vj1-8u
old condensing unit;f3ah-a078-Iaa-001
new condensing unit;aka9446exaxc
lines 1\2",1\4" ,80 feet long.
solenoid valve on liquid line.
the bottom grill is covered with paper costumer says that`s the way it always worked.Tells me in three years no body touched the unit.(yaa right..)
I checked the compressor;internal relief is blown.Sold the new condensing unit on the spot and a fan control and an LPC.When I opened the box I called my boss to tell him that it looks smaller than the old one especially the receiver.He tells me the supplyhouse crossreferranced it.I put everything together.Meanwhile while charging the unit I realize that one of the two fans in the salad show case is not working.Took care of it.
Here`s the saga;
first the box wouldn`t go below 44*F.expansion valve has no cap so I suspected it was mingled with.there is flooding back.tried to increase the superheat couldn`t.next day brought 1\2 ton valve with ext.equ. installed it.flooding back.gave it half a turn solved the problem.recovered the excess R22.showed the costumer 25*F to convince him.meanwhile since the first day I know system can not pump down on solenoid; head pressure skyrockets.so left the cut out setting high enough to enable turn off.made my boss aware of it.had a call-back first in three months in this job.found that expansion valve leaks from the header.fixed it and left.had a call- back saturday morning,.that compressor is very hot its clicking and no cooling.went there to see the internal relief blown,or leaking internally.told the costumer will be back monday,supplyhouse is closed ,boss is hunting.he bags me.i enable the compressor to start and run provided he opens the doors to prevent salad from freezing.because it can not stop.turned the thermostat all the way down.he survived weekend that way.monday I pick up another compressor under warranty and install it.jumped out the thermostat adjusted the LPC for temperature control.with no pump down hoped there will be no crazy jump in head pressure.sure enough when the low side reaches 35-37 psi (box is about 36*F)all of a sudden head pressure skyrockets before I pull the breaker off.adjusted LPC little higher not to see this situation before I come back with a new expansion valve.( my boss suspected that the leaky expansion valve was taken apart by previous mechanics)next day replaced the expansion valve.gave boss the good news and left.(I am not getting into the business aspect of this saga).This morning had a call-back..compressor is dead.internal relief open.couldn`t even get the compressor run this time after all the tricks that I know.I forced the costumer to admit that two weeks before the origenal compressor failed he had freon put into it.because he was asking me how come in three years there was no high head pressure problem.(by the way I showed him the date scrached on the origenal condensing unit 6.12.2002)My explanation to him was maybe someone put air inside the system or overcharged it till the oil broke down and coated inside the condenser(these parts are actually my question to you guys)or are you sure someone didn`t add some kind of oil or put wrong refrigerant to screw up the oil?)the origenal compressor died of high head pressure.either the condensor was dirty,we can`t know it now because its clean at the moment,or it was over charged I could not know it,or in time the oil broke down because of air in system and insulated the condensor coil.so he was left with these options from my boss;take another one of the same compressor in its box we`re not installing it.or upgrade the condensing unit preferably the piping also for a cost and labor charge.If I was the costumer I would buy a whole new system.So what do you think,besides that it a long story.sorry I couldn`t help.