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  1. #1
    Join Date
    Sep 2003
    Posts
    86
    Can someone please help me diagnose a carrier wastewater cooled heatpump.It locks out after running awhile and I dont want to mess it up any.I think someone else has been monkeying around,some of the cover screws were off and laying on top.At any rate,here are the facts.Unit has an expansion valve.Temp in at the filter is 73degrees.Temp out at grille is 57 degrees.Suction pressure is 43#.Suction line temp taken 3 inches from compressor is 81 degrees.Head pressure is 195#.Liquid line temp at the distrubtor at evaporator coil is 37 degrees with frost on it.Compressor discharge temp at compressor is 158 degrees.Cooling water temp in is 51 degrees,water temp out is 100 degrees,both temps taken where lines enter the cabinet. The ambient temp in the room is 75.The unit is drawing 6.8 amps on one line and6.7 amps on the other.The nameplate rla says 8.7.This is a r-22 unit.Model # 50RHR024SCC30130.All these readings unit is in the cooling mode.The room that it is in has a UPS system so it has this unit to cool area.Up till now it has worked fine.Any thoughts comments or opinions are welcome.Thanks very much.At first my inclination was to recover the charge and weigh in a new one,but I thought maybe I would seek some advice.

  2. #2
    Join Date
    May 2004
    Location
    Los Angeles, CA
    Posts
    1,560

    You have at least two seperate problems......

    Dear Mark7,

    Based upon the information you posted, you actually have at least two separate and different problems with this 2 ton Carrier system. First of all to clarify something, the “liquid line” temperature you recorded at the distributor at the evaporative coil is neither liquid nor suction temperature, you actually obtained the temperature in the wrong place. The combination the system’s TXV “AND” the distributor is the metering device for this system, you measured in-between these components. Your measured superheat, the difference between the suction line temperature at the compressor and the saturated suction temperature is a whopping 61 degrees F, way too high. The ice on the distributor indicates that the surface of the distribution cone is below 32 degrees F. The supply/return delta T is only 16 degrees F, this is too low. And your process water entering and leaving water temperature delta T is a whopping 49 degrees F, way too high as well.

    In conclusion, this system is low on refrigerant, and the process water flow is too slow, therefore to repair this system would require two things. First, charge the system, weighting in the charge is a good way to accomplish this, second increase the water flow through the system’s heat exchanger. This could indicate low entering pressure or a restriction in either the heat exchanger or the drain line out of the system; you’ll have to investigate that one.

    Good luck in your repairs, and let us know how it turns out.

    Respectfully Submitted,
    John J. Dalton

  3. #3
    Join Date
    Jan 2005
    Posts
    175
    I have seen systems that had gas removed to compensate for water flow problems or fouled water cooled condensers that people were too lazy to investigate or repair.


    [Edited by wasp on 02-06-2005 at 02:49 AM]

  4. #4
    Join Date
    Sep 2003
    Posts
    86
    After leak checking unit with an electronic tif detector and soap,I didnt find a leak.I opened up on the water controller valve and brought head pressure down to 175#.The suction pressure is at 47# and line temp is 67 degrees at the compressor.The compressor discharge line temp is 150 degrees at the compressor.The water in is 50 degrees and water out is 90 degrees.It is drawing 6.7 amps data plate says 8.7 rla.The discharge air temp is 47 degrees at the grille, the return air is 66 degrees.I did add some refrigerant.Am I taking the temp readings in the right spot,right by the compressor?Any help is greatly appreciated.I probably will pull the charge anyway,but I am the only one on duty and the phone is ringing every 10 minutes for something else.The coil is very clean and so is the filter by the way.Thanks for any help.

  5. #5
    Join Date
    Sep 2003
    Location
    western canada
    Posts
    373

    Re: You have at least two seperate problems......

    Originally posted by john dalton
    In conclusion, this system is low on refrigerant, and the process water flow is too slow, therefore to repair this system would require two things. First, charge the system, weighting in the charge is a good way to accomplish this, second increase the water flow through the system’s heat exchanger. This could indicate low entering pressure or a restriction in either the heat exchanger or the drain line out of the system; you’ll have to investigate that one.

    You may want to leak check and if there is a leak, fixit it before recharging. Cheers.
    work to live not live to work

  6. #6
    Join Date
    Jun 2001
    Location
    San Diego, CA
    Posts
    1,149
    the deltaT on your water in/out should be 10degrees or less. Your condensor needs a flush and/or the strainer or flow restrictor is partially clogged or the valves a throttled or . . .

    once you get the water split right, then you can get the refrigerant right.

  7. #7
    Join Date
    Jan 2005
    Posts
    604
    I tend to agree with John.

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