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Thread: Condenser pressure drop circuit 1 restriction

  1. #21
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    Quote Originally Posted by VTP99 View Post
    What's the possibly your reversing valve is bypassing some low side pressure ?
    We checked suction temps passing through reversing valve. Only 1-2 degrees difference. No sign of bypassing.

  2. #22
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    Did you check the TD across the condenser ?

  3. #23
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    Quote Originally Posted by VTP99 View Post
    Did you check the TD across the condenser ?
    No.

    What should be the estimated TD? 25-30?

    What if it does not meet the recommended TD? If to low due to not enough heat rejection.

  4. #24
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    It's a triple coil that's probably never been split and cleaned.

  5. #25
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    Quote Originally Posted by Elite-Mech View Post
    Correct, verified by analog gauge.

    The first liquid line comes out of condenser through check valve into outdoor txv distributor then back into condenser to get cooled again comes out of condenser tee's off to outdoor txv and indoor metering device (biflow piston).

    The access port we installed is on the main liquid line between evap and cond. We are going to install access port on the first liquid line as soon as it exits condenser.
    So you have a checkvalve and txv/distributer and Sub cooling loop between your access tees.
    Put a bullet tap in the LL after the condenser. Quick and easy.
    Then, when you've found the problem and have to pull the juice out anyway for repair purposes, remove the bullet and install proper port or just braze the pin hole closed .


    Sent from my SM-G950U using Tapatalk

  6. Likes VTP99 liked this post.
  7. #26
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    Quote Originally Posted by icy78 View Post
    So you have a checkvalve and txv/distributer and Sub cooling loop between your access tees.
    Put a bullet tap in the LL after the condenser. Quick and easy.
    Then, when you've found the problem and have to pull the juice out anyway for repair purposes, remove the bullet and install proper port or just braze the pin hole closed .


    Sent from my SM-G950U using Tapatalk
    Yes, Correct.

  8. #27
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    Quote Originally Posted by VTP99 View Post
    It's a triple coil that's probably never been split and cleaned.
    Got it.

    But will that issue cause a 50 psi drop? Wouldn't the psi remain the same whether its low or high?

  9. #28
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    Vtp?
    Why is the discharge pressure so low for that ambient ?
    It's a triple coil that's probably never been split and cleaned.
    These statements contradict each other
    Honeywell you can buy better but you cant pay more

    I told my wife when i die to sell my fishing stuff for what its worth not what i told her i paid for it

  10. #29
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    Quote Originally Posted by crazzycajun View Post
    Vtp?
    Why is the discharge pressure so low for that ambient ?
    It's a triple coil that's probably never been split and cleaned.
    These statements contradict each other
    Yep he should have higher then normal head pressure.
    But it might be one piece in the puzzle why it isn't.
    I'm not sure how the circuits in those coils are divided up.
    I'll assume top half bottom half.

    I'll also assume both stages are calling unless somehow first stage is holding temp at 79 outdoor ambient.

  11. #30
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    Sounds like the condenser coil is restricted could be from wax/varnish. I had once that was stopped up with blue plastic beads from the factory

  12. #31
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    Power head loss of charge

  13. #32
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    Update

    R22
    85 ambient
    Discharge 240, LL 160, subcool liquid line120psi, suction 50 psi

    With compressor door panel removed
    Discharge 300, LL 195, SCLL 150, suction 75psi

    Seems like condenser is partially plugged

  14. #33
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    Put a tap in the discharge line entering the coil, put a tap at the first liquid leg leaving the coil.

    Then put one on the subcooler line entering the coil, and another at the subcooler leaving the coil.

    That will allow you to check just the condenser coil drop, and just the subcooler loop pressure drop.

    This will allow you to determine what exactly is plugged, and make a plan.

    Once you determine which coil is plugged, you can do as someone else mentioned....use a tube cutter to remove the coil header, and see what's in it.


    Also, when you stack refrigerant in a condenser coil, the fans will cool the liquid. This causes Lower than expected head pressure.

    I also wonder if the coil being plugged is allowing some of the hot gas to make it through the coil, causing your low subcooling reading.

  15. #34
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    Quote Originally Posted by 71CHOPS View Post
    Put a tap in the discharge line entering the coil, put a tap at the first liquid leg leaving the coil.

    Then put one on the subcooler line entering the coil, and another at the subcooler leaving the coil.

    That will allow you to check just the condenser coil drop, and just the subcooler loop pressure drop.

    This will allow you to determine what exactly is plugged, and make a plan.

    Once you determine which coil is plugged, you can do as someone else mentioned....use a tube cutter to remove the coil header, and see what's in it.


    Also, when you stack refrigerant in a condenser coil, the fans will cool the liquid. This causes Lower than expected head pressure.

    I also wonder if the coil being plugged is allowing some of the hot gas to make it through the coil, causing your low subcooling reading.


    Correct.

    The updated pressures listed above are the pressures with the taps in the location you mentioned.

    We are going to cut, isolate lines and try a solvent flush to see what kind of debri if any comes out.

  16. #35
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    When you say "external check valve on outdoor txv" do you mean that it is a visibly separate component, right next to the valve? The kind I'm thinking of has a screen in it, and will get plugged up and cause problems like low suction pressure. I never knew that screen was in there before, and spent a day or two staring at a unit that kept running right at the verge of freezing up all the time after a compressor changeout. If its pretty bad, you should be able to feel it getting cold.


  17. #36
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    Quote Originally Posted by CHAINIK View Post
    When you say "external check valve on outdoor txv" do you mean that it is a visibly separate component, right next to the valve? The kind I'm thinking of has a screen in it, and will get plugged up and cause problems like low suction pressure. I never knew that screen was in there before, and spent a day or two staring at a unit that kept running right at the verge of freezing up all the time after a compressor changeout. If its pretty bad, you should be able to feel it getting cold.
    Yes correct it is next to the outdoor txv. There is not a temp difference across check valve. There is a large pressure drop exiting first liquid line immediately exiting condenser, so customer wants to flush with solvent.

  18. #37
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    Sounds like you got it figured out.

    I would convince them to let you cut the header off completely. It's really not that much work to put it back together with some couplers.

    Just had a recip. Job go to he!!....replaced compressor, removed head and found a piston missing. Had to cut out the head pressure control valves to clean compressor parts from them. One had a screen. It was all really only an additional hour or so on the job.

    Take the time up front to eliminate a call back on the tail end!

  19. #38
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    Quote Originally Posted by Elite-Mech View Post
    Correct.

    The updated pressures listed above are the pressures with the taps in the location you mentioned.

    We are going to cut, isolate lines and try a solvent flush to see what kind of debri if any comes out.
    I had an old Trane 5 ton gas/electric RTU with a high condenser pressure differential...never did the surgery on it so will be very interested in seeing what you find.

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