Hi everybody. i am new in this form. now i am in serious trouble. i hope some one in this form can help me out. i am working in a caribbean islands and we dont have much air conditioning guys here to help me out.
problem. i installed one used 40 ton water cooled unit and used 5H40 carrier compressor. this compressor i know it is good and i were uisng this compressor last six years with out any problem on other system. but now i am using R22 refrigerant and am getting 35 psi suction pressure and 150 psi discharge pressure. i know this unit is enough refrigerant and i am not feeling heat on the discharge side copper tubing too. . also i have good water flow throught the condensor and evaporator. also saw ice on the comprressor both side. what may causes low suction and low discharge pressure?. do you think it is because of TXV. ( TXV is came with this used unit). what i should do . i am having 82 F ambient temparature . so help me out
islandcool,it sounds to me like you have too low discharge pressure. i would expect 225 - 250 psi if you have 82 F ambient. i assume you have tower water return around 75 -80 deg. is the water cooled condenser part of a package with that 5H40?best bet is for you to give full log of machine water in and out , liquid line temp and press, suction line temp and press.
what is this feeding AHU DX or chiller? TXV size ?
5H40 on r22 should be 40 tons if memory serves me right. TXV should probably be sized at 26 tons at 100 psi drop across it
You really haven't given us enough information to work with here.
What kind of unloading are you using for this compressor?
Internal, external? If external, are the internal ports plugged?
You definately have issues but I doubt it's your refrigerant circuit.
How do you KNOW you have enough of a charge? Did you measure it?
Are you using the sight-glass for charging? Weight? What is the subcooling on your condenser? What are the EWT and LWT of your condenser and evaporator. What are the flow rates of your condenser water and evaporator water?
Did you pull a proper evacuation between compressors?
Post something we can work with.
ps the 5H40 for high temp refrigeration is rated at 38 tons.
Which island? Maybe one of us could come down and help you out.
Hey Wolf.. I was thinking the same thing, but I already live in the tropics. Had it been Northern Canada, I'd have tossed that out there.
With the limited info. it sounds like the compressor is running fully loaded with a low charge. Run in the unloader stem until the compressor unloads. You will have several steps of unloading and should leave the "control point" at approx. 62 psi on r-22. The unloader control is under the round cap on the oil pump end. If you have external means of capacity control the most common method is a pneumatic connected just above the unloader stem on the oil pump. The other means, as discussed by others, involves several external oil lines connected to various ports around the housing of the oil pump/bearing assy. That method is not widely used.
If you want info. that clearly identifies your problem, you will have to provide the temperatures of the compressor lines as well as the pressures.
The readings you need are listed by several others.
The compressor you are working on has a reputation of being very tough.
We installed some systems in your area years ago for Blue Bell/Wrangler.
The man said "I see ice forms on both sides of the compressor". Then how can we tell the man his system is low on charge??????????????
At what temperature/pressure can you create frost?
Its not a 6L40 but a 5H40. Open drive with only the heat of compression and friction to warm the compressor casing.
With the info given he needs to take several steps just to provide enough info to point him in the right direction.
Is it fully loaded = 35 psi could be from a low side starved of refrigerant with the compressor being manually set to run at its full 40 tons,(or more with a lower condensing/higher suction)
Is the superheat low = Is it flooding so bad from lack of temperature exchange he is not boiling off the liquid..wouldn't run long with that much floodback but I have seen it on many fouled systems...
but then we have the low head pressure to add to the equation...
Is it starved from a TXV not feeding.....a liquid line drier with a problem,
He also said the compressor ran on another system...
Is the TXV the proper one for the capacity and the refrigerant?
What unloader spring is he running in the capacity control on the compressor?
If he changed refrigerants he may have the wrong spring range for the pressures.
If he does as suggested and checks the capacity control the information he brings back will, as I stated, allow someone to point him in the right direction.
The man said "both side of compressor have ice" "the discharge line is cool"
Then How can we tell the man
a) it is low on charge
b) It is starving of freon on low side.
My questions are:
"I have good water flow" ---- how good is good
"I have enough freon in the system" ----- how enough is good enough
Please give us more info man