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Thread: Ref Plus

  1. #1
    Join Date
    Dec 2009
    Location
    Ontario , Canada .
    Posts
    95

    Ref Plus

    Insufficient cooling . Condensing uint , consisting of an Carlyle 06DA compressor and glycol cooled condensor with two cylinder unloaders and hot gas bypass, located in basement of 8 floor building . Serving two stage evaporator same floor . Three years old . The condensor has no gauges or thermometers , has a pump supplying the condenser ( a small Armstrong pump) . R-407C .
    So disconnected unloaders and hot gas , both stages calling , return air 74 deg . Liquid line flashing , low suction pressure , 45 psig , 225 high side . Low refrigerant charge , right ?
    Leak checked , right unloader stem leaking , everything else looked great . Isolated compressor ,replaced stem , evacuated compressor . Added 12 lbs of 407C . Head pressure increased to 285 psig , saturated liquid line and hot . Opened water cooling valve ALLL THE WAY with little effect . Delta T across condenser , maybe 5 deg f ?? System occasionaly cutting out on high head but did not catch cut out .
    The system rejects its heat through a dry cooler that supplies heat pumps in the building . Increased the speed of vfd pump at dry cooler to 100 % . Bypass valve fully open , no diversion of fluid to dry cooler . Glycol temp 75 deg supply temp to condensor . Still head pressure would not drop . The load to the evaporator is low at approx 72 deg return air . \

    Any ideas as to why my head pressur is so high ?? My delta t seams low accross the condensor , compressor is fully loaded my liquid line is still satureated and hot . I dont want to add any more refrigerant . Did not check for air in system , ran out of time Friday afternoon .

  2. #2
    Join Date
    Dec 2006
    Location
    Somewhere in Canada
    Posts
    84
    R407C is a high glide product .... did you add the refrigerant in the liquid mode? All 400 and 500 series refrigerants must be added to a system as a liquid.

  3. #3
    Join Date
    Dec 2009
    Location
    Ontario , Canada .
    Posts
    95
    Quote Originally Posted by Ph-D View Post
    R407C is a high glide product .... did you add the refrigerant in the liquid mode? All 400 and 500 series refrigerants must be added to a system as a liquid.
    yes

  4. #4
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,611
    Check the obvious before going further: non-condensables, tube obstruction, tube fouling. If that don't clear it up, you need to post accurate readings ("liquid line is saturated" is not an accurate reading) of the entire unit operation.

  5. #5
    Join Date
    Dec 2009
    Location
    Ontario , Canada .
    Posts
    95
    Quote Originally Posted by klove View Post
    Check the obvious before going further: non-condensables, tube obstruction, tube fouling. If that don't clear it up, you need to post accurate readings ("liquid line is saturated" is not an accurate reading) of the entire unit operation.
    If opportunity prevails , this will be the first thing I need to check . Just not enough time on Friday . Air would be my first hope in this issue . Gauges would have to be installed across the condensor to prove flow characteristics . What a pain in the but . Just started this job , dont need an engineer to do me in . The guys have been checking this thing for two years now , I cant wait to hear the comments monday morning , LOL .

    Thanks Klove

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