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  1. #14
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    Jun 2019
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    Thread Starter
    Thanks for the reply. It is an old system and the compressor and the pump is make some noise already.

  2. #15
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    Quote Originally Posted by rider77 View Post
    Depends on a few things, but if it’s got a certain style of head pressure control your likely low on refrigerant.

    Vtp99 and rider have you covered
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  3. #16
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    Oct 2016
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    Could very well be low on refrigerant but why it would be hot and then get cold is a bit odd.

    When is there traffic in the cooler? During the night or during the day? If it was low I would give it the best odds of hitting setpoint when no one is walking in and out.

  4. #17
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    Quote Originally Posted by Olivero View Post
    Could very well be low on refrigerant but why it would be hot and then get cold is a bit odd.

    When is there traffic in the cooler? During the night or during the day? If it was low I would give it the best odds of hitting setpoint when no one is walking in and out.
    It's an outdoor condensing unit with most likely a HPC valve.
    It will bypass the condenser when low on charge. Would need the extra refrigerant to flood the condenser coil in low ambient conditions.

  5. #18
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    Jun 2019
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    Thread Starter
    Thanks for replying. It is a beer cooler and we are open 5.30 am to 11.00pm so no traffic during the night.

  6. #19
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    Jun 2019
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    Thread Starter
    Is it because it gets hot in the day and pressure within the system increases?

  7. #20
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    Quote Originally Posted by joylexeme View Post
    Is it because it gets hot in the day and pressure within the system increases?
    Yes less refrigerant going to the condenser and more for the system.

  8. #21
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    Oct 2016
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    Clearwater, Florida
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    Hmm.

    Sounds interesting. How could it cool if it's bypassing straight to the TXV again though? When would it turn into liquid? From ambient cooling?

    "Outside temp is about 50F at night and 85F by late afternoon. What could cause this?"

    If it's 50*F out at night, wouldn't the system have a better chance of cooling at that point? Considering there's no traffic in the fridge so not a heavy load, ambient's cold enough to cool everything down (somewhat) and so it could in theory do a crappy job of cooling during the night, but why is it fine during the day? IF that refrigerant doesn't condense, the TXV would not work right.

  9. #22
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    The HPC will try to maintain X amount of head pressure depending on which refrigerant being used.
    So at night when the ambient drops (pressure falls) it's tries to load up the condenser with liquid to lessen the condenser surface area. Which with a properly charged system would elevate the pressure. We call this flooding the condenser.

  10. #23
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    Nov 2006
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    Quote Originally Posted by VTP99 View Post
    The HPC will try to maintain X amount of head pressure depending on which refrigerant being used.
    So at night when the ambient drops (pressure falls) it's tries to load up the condenser with liquid to lessen the condenser surface area. Which with a properly charged system would elevate the pressure. We call this flooding the condenser.
    ...and with a low charge, when the condenser is flooded, there is not enough liquid left for the TEV.
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  11. #24
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    Aug 2002
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    Quote Originally Posted by Olivero View Post
    Hmm.

    Sounds interesting. How could it cool if it's bypassing straight to the TXV again though? When would it turn into liquid? From ambient cooling?

    "Outside temp is about 50F at night and 85F by late afternoon. What could cause this?"

    If it's 50*F out at night, wouldn't the system have a better chance of cooling at that point? Considering there's no traffic in the fridge so not a heavy load, ambient's cold enough to cool everything down (somewhat) and so it could in theory do a crappy job of cooling during the night, but why is it fine during the day? IF that refrigerant doesn't condense, the TXV would not work right.
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  12. #25
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    Oct 2016
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    Quote Originally Posted by timebuilder View Post
    ...and with a low charge, when the condenser is flooded, there is not enough liquid left for the TEV.
    Ah, with that little addendum I understand what VTP99 is trying to esplain to me.

    Okay, got it. I can't even think with a low ambient like that.

  13. #26
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    Jan 2010
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    Per pecmsg
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