First of all, there was a reason why the old compressor locked up and without finding out the reason why the problem is following the new one. The hissing that you are talking about is it coming from the compressor? If it is it sound like it is the internal pressure relief going off, this noise should come and go. Yes you do have a problem, and it could be a number of reasons but you need to find out the right one or you will spend more money than it would have cost a service man to repair, at least if he did it you could go back to him.
1. Was compressor burnt at time of lockup?
2. did you change the drier?
3. is it correctly charged?
4. Is TXV feeding properly?
let me know and maybe i can help.
Testimonial: "Very helpful tip!! Thanks"
I did change the filter drier and purged lines with nitrogen to make sure there wasn't a restriction. My pressure are 100 head and 50 on suction R-22 system. One thing i noticed was i wasnt getting any activity in my sight glass but the system was running fine. Now the hissing is constant and it doesnt come and go. I'm a journeyman hvac tech but I work on residential and light commercial HVAC. I havent done much refrigeration work in a while. I think the TXV is the issue but im not sure if the compressor is ok now?
Have you checked the superheat on the txv? when you told me the pressures on the gauges you didnt mention the box temp at those pressures. when you had the system open did you remove the screen from the txv and clean it. is it water cooled or air cooled? let me know.
also you need to tell me is this high temp, med temp, low temp or xtra low temp?
The box temp was 60 degrees. no i didnt clean a screen on txv and the refrigerator is air cooled and is an open display case that runs 35 to 40 degrees. Im not getting any activity out of my sight glass. Havent checked superheat because nothing is happening at txv.
do you know how to check valves in compressor?
yea front seat liquid line king valve right? Everytime i start the compressor up it goes into internal pressure relief.
WRONG!!! put guages on unit, jump out low pressure control so unit will stay running, front seat suction valve and let unit run, suction side should go into vacumn, (this may take a while but has to go into vacumn) once it is in vacumn, front seat discharge valve on compressor. as soon as you front seat the discharge valve cup power to unit, and watch gauges. If compressor does not pump down by first step, suction valves are bad. if pressures equilize after 2nd step discharge valves are bad. are you by equipment now? let me know.
Ok thanks im going to try that at 2 oclock. I appreciate all your time. I will let you know what I find.
what did you find?
Found bad suction valves. Front seated suction valvew would not pull into a vacuum. Here's my next plan of attack replace compressor, filter drier and TXV thats probably what I should have done from the start.
If it is a semi hermitic compressor, change the valve plate. If you change compressor make sure you change all start components. Make sure you pull a good vacumn on system. Then check txv, since you have service valves you can move the refrigerant around to change the txv if you need to but make sure you clean screen on inlet side of txv. How about a testemonal would be great. let me know what you do.
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Im trying to re- design an open air produce case at my fathers grocery store. The old design had a burnout on old compressor, because lack of oil , oil had accumalated 15 foot from evaporator [ vertical ft ] suction line was sagging. old design went another 180 ft out to mechanical room where the condensor, compressor ,and controls were located . ambient temperatures in the summer exceeds 110 degrees in room . and the old copper lines are ran overhead because original market layout ran underground in concrete when R-12 was used. the reason why im asking for your advice is simple.with the economy being in the state its in financial resources for repairs are tight. to repair it with old design would be very costly . i have a goodman condensing unit from a heat pump system that will fit on top of case eliminating 195 feet of copper suction and discharge lines [ same concept as our ice box] is this design even feasable .To improvise this old equipment at as little of a cost as possible is my goal. If you can help would be much appreciated.
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I did change the filter drier and purged lines with nitrogen to make sure there wasn't a restriction. My pressure are 100 head and 50 on suction R-22 system. One thing i noticed was i wasnt getting any activity in my sight glass but the system was running fine. Now the hissing is constant and it doesnt come and go. I'm a journeyman hvac tech but I work on residential and light commercial HVAC. I havent done much refrigeration work in a while. I think the TXV is the issue but im not sure if the compressor is ok now?
The box temp was 60 degrees. no i didnt clean a screen on txv and the refrigerator is air cooled and is an open display case that runs 35 to 40 degrees. Im not getting any activity out of my sight glass. Havent checked superheat because nothing is happening at txv.
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