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  1. #1
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    Foaming from King Valve

    Oops, I think I put this in the wrong forum first. If you have the ability to delete it from General discussions, then please do so. Also had a post about testing oil that should be moved here also. Sorry.

    Prior to repairing a hole in a condensor coil yesterday, I closed the low side king valve as part of isolating the system. As I started to close the valve, a dense persistent foam leaked from the valve. No surprise on the leak, likely overheated by the original installer. However, I have not seen this type of foam come out of a system before. It wasn't quite like shaving cream, more like the thick head on a stout Guiness, but it was close. I didn't have an acid test with me, but the foam didn't burn my fingers as I expected it would ( I know, I should have been wearing gloves).

    I would greatly appreciate your thoughts on what this foam indicated.

    Unit was a 15 year old York 5 ton heat pump (R-22)

  2. #2
    Join Date
    Jan 2012
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    Found a darker gray foam out of a 15 yr old Rheem hp suction port, only leak I found. Recharged and did not fully open the valve, leak stopped. Still operates 4 yrs later.

  3. #3
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    Maybe this isn't a major issue then. I'd hate to leave a customer with soon to occur compressor failure that I didn't warn them about. Thanks.

  4. #4
    Join Date
    Nov 2014
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    western NY
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    Am i the only one that is confused as to why you would close the suction service valve to try and isolate system while fixing a leak in condenser coil?
    Do it right or do it thrice. you choose.

  5. #5
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    Jan 2012
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    On heat pumps I pump the refrigerant into the air handler.

  6. #6
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    Maybe I should have used the term "suction line service valve" instead of "king valve". The leak was in the condenser coil of a split system. Trying pump into another part of the system, the air-handler, would have risked two things: 1) sucking air in through the hole in the condenser coil 2) burning up the compressor with no refrigerant from the low side to cool it.

    The temperature at the evaporator coil was below the outdoor temperature of the condenser. So, any liquid refrigerant should already have been accumulating in the evaporator.

    What do you call the valves you open to release the charge into the evacuated lines on a new install with a pre-charged condenser? Maybe I am all washed up, but if I don't want/need to pump down an entire system then why would I.

  7. #7
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    Seriously, I guess I am a total hack.

    Maybe I should have used the term "suction line service valve" instead of "king valve". The leak was in the condenser coil of a split system. Trying pump into another part of the system, the air-handler, would have risked two things: 1) sucking air in through the hole in the condenser coil 2) burning up the compressor with no refrigerant from the low side to cool it.

    The temperature at the evaporator coil was below the outdoor temperature of the condenser. So, any liquid refrigerant should already have been accumulating in the evaporator.

    What do you call the valves you open to release the charge into the evacuated lines on a new install with a pre-charged condenser? Maybe I am all washed up, but if I don't want/need to pump down an entire system then why would I

  8. #8
    Join Date
    Jan 2013
    Location
    florida
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    if the leak is in the condenser you will need to recover the entire charge, or what's left of it to repair...

  9. #9
    Join Date
    Feb 2016
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    The foam comes from oil that has migrated through the system due to low charge. I would be concerned about contaminants(air) in the system if the charge got low enough and the unit could have pulled into a vaccum and sucked air into the system. The foam is just refrigerant boiling out of the oil.

  10. Likes HellGato liked this post
  11. #10
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    Mar 2016
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    The system wasn't running on arrival due to a blown fuse in the air handler. Had 100 psig when we started looking for the leak. Found said leak under the galv. steel supporting the end of the coil. Lost pressure rapidly when I tried to see how much play there was around the support. Big mistake! Probably should have pumped down/recovered first.

  12. #11
    Join Date
    Feb 2016
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    If in Doubt Pump it out! Saves you headache later. As far as leak on steel support, you can try to repair it. Its going to sprout another leak later. Let your customer know that and give them the option of trying to repair the leak or replace unit.

  13. #12
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    No money for a replacement. New baby in the family. Got the leak repaired, rewired a whole bunch of bad connections that likely led to a burned out defrost control board and blown fuse. Avoided getting bit by the 120# dog protecting the baby. Saved the customer at least $4,000 over a replacement. If they make it through the summer cooling season, they will be happy even if they have to go to aux./em. heat next winter.

  14. #13
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    Feb 2016
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    Nice! You did what you could do and let the customer know of problems in the future. They will call you back.

  15. Likes David Goodman liked this post

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