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  1. #14
    Join Date
    Oct 2011
    Location
    Chicagoland Area
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    6,431
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    If the defrost heaters are energized during the cooling cycle, there is something wrong. A stuck relay or a bad board.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  2. #15
    Join Date
    Aug 2014
    Location
    Los Angeles
    Posts
    61
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    Thread Starter
    Quote Originally Posted by 2sac View Post
    If the defrost heaters are energized during the cooling cycle, there is something wrong. A stuck relay or a bad board.
    got you! thank you for your help!

  3. #16
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    16,107
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    Did you change the drier when you recharged?

    Does this unit have a receiver? If yes is the SG Clear?

    Why cant you get a SH reading at the evaporator? SH at the pump can still be checked with a subcooler!

    CPR valve gets set coming out of defrost, it keeps the compressor from over-amping during pull down. Post the model #'s of the pump and well tell you the setting.

  4. #17
    Join Date
    Aug 2014
    Location
    Los Angeles
    Posts
    61
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    Thread Starter
    Quote Originally Posted by pecmsg View Post
    Did you change the drier when you recharged?

    Does this unit have a receiver? If yes is the SG Clear?

    Why cant you get a SH reading at the evaporator? SH at the pump can still be checked with a subcooler!

    CPR valve gets set coming out of defrost, it keeps the compressor from over-amping during pull down. Post the model #'s of the pump and well tell you the setting.
    Hi, i didn't open the system, so i did not change the liquid line drier. the system doesn't have a SG. I can take the temps reading after the TXV bulb, but i can only have pressure reading after CPR. if the CPR always keep the same pressure after its outlet, i need a pressure reading before its inlet, but there is not a service valve. if this is true, that is why my lowside pressure never change(10 psig) even when you pump down the system? you said i can use the subcool value to check the superheat because when the system doesn't have any issue, the superheat value = subcool value? this unit carries a logic board to use to control defrost and cooling cycle, the transformer and two sensor connectors(box&evap coil) are also in there. thank you for your time!
    manufacture: master-bilt
    model: BLG-27HD

  5. #18
    Join Date
    Sep 2016
    Location
    Saint Johnsville NY
    Posts
    28
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    I've had the pressure valves stick on me. More than likely it's a 0-60 cro. Put the case in defrost and when it comes back on you should set the pressure jump up some afterand then drop as the coil cools off is the icing to the cro it sounds like it is low still if valve functions correct

  6. #19
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    16,107
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    Quote Originally Posted by david170 View Post
    Hi, i didn't open the system, so i did not change the liquid line drier. the system doesn't have a SG. I can take the temps reading after the TXV bulb, but i can only have pressure reading after CPR. if the CPR always keep the same pressure after its outlet, i need a pressure reading before its inlet, but there is not a service valve. if this is true, that is why my lowside pressure never change(10 psig) even when you pump down the system? you said i can use the subcool value to check the superheat because when the system doesn't have any issue, the superheat value = subcool value? this unit carries a logic board to use to control defrost and cooling cycle, the transformer and two sensor connectors(box&evap coil) are also in there. thank you for your time!
    manufacture: master-bilt
    model: BLG-27HD
    As said put the unit thru a defrost, have your VOM on the compressor and low side gauge hooked up, coming out of defrost the pressure and amperage will spike then settle down for a few sec or a minute. That's the CPR setting. as the pressure and amperage goes down the CPR os out of use.

    Get the SH at the pump.

  7. #20
    Join Date
    Aug 2014
    Location
    Los Angeles
    Posts
    61
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    Thread Starter
    Quote Originally Posted by pecmsg View Post
    As said put the unit thru a defrost, have your VOM on the compressor and low side gauge hooked up, coming out of defrost the pressure and amperage will spike then settle down for a few sec or a minute. That's the CPR setting. as the pressure and amperage goes down the CPR os out of use.

    Get the SH at the pump.
    yes, when the unit start to defrost, the cooling cycle stop, i can see the low side pressure going up to 25 psig; when coming out of defrost, the lowside back to 10 psig and stay there forever. it is looks that the CPR is not block the stream and keep wide open at normal cooling cycle, i measured the compressor superheat is around 60 F.
    another thing is that sometime when coming out of defrost, the condenser unit start running only 2 minutes, the heater energize again! then back to cooling cycle, when coil temps drop to 30 F, evap fan start running, but the box temps will not satisfy at setting point. I check the txv, it is not plug there. thanks!

  8. #21
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    16,107
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    Turn the adjustment all the way in to open it up. 10#’s is too low

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