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Thread: Interesting job

  1. #1
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    Interesting job

    Guess I should say interesting service call. About a month ago, one of our mid level techs went on a job and told the office he'd like to go back to the job with me. For a second set of eyes. Got the approval to do one of the suggested repairs, which I did today.

    I found three separate areas with major problems. The one I'm going to talk about was when the unit was running, the head would get so high it would trip out in awhile. But the liquid line was cool and there were bubbles in the sight glass.

    R-22 heat pump, and with the unit off, the temp pressure relationship was about as nuts on as you could get for a split system. Seven and a half ton unit.

    The actual number for the subcooling was 50*F. That is, if it was really R-22 in the system.

    You could tell that there were many hands inside this unit. Equipment didn't really look in that bad of shape, considering it was about ten years old. But that's because it's never been run much. According to the manager who has been there since it was installed.

    Short of installing a whole new system, which the property owner wasn't willing to buy into since the last time they did that they didn't get any value for their bucks. I broke the repairs into several portions.

    So anyway, I recovered 32 pounds of who knows what, pulled a good evacuation, then recharged with 25 pounds of R-22 . . .

    And everything worked. LOL

    I was seriously not sure if it was or not. But I did my due diligence on the initial visit, crunched all of the appropriate numbers, did the calculations [since I don't have digital gauges] [the math took me like what, twelve and a half seconds, LOL], looked at the fans and blowers [no apparent restrictions], etc.

    Didn't even change the driers. Because there was no apparent reason to. And because of the way Trane built a two drier check valve arraignment ten years or whatever ago.

    After recharging, everything was perfect.

    Still don't have a clue what was in that system, but it's all in a recovery bottle now.

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  3. #2
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    Quote Originally Posted by BBeerme View Post
    Guess I should say interesting service call. About a month ago, one of our mid level techs went on a job and told the office he'd like to go back to the job with me. For a second set of eyes. Got the approval to do one of the suggested repairs, which I did today.

    I found three separate areas with major problems. The one I'm going to talk about was when the unit was running, the head would get so high it would trip out in awhile. But the liquid line was cool and there were bubbles in the sight glass.

    R-22 heat pump, and with the unit off, the temp pressure relationship was about as nuts on as you could get for a split system. Seven and a half ton unit.

    The actual number for the subcooling was 50*F. That is, if it was really R-22 in the system.

    You could tell that there were many hands inside this unit. Equipment didn't really look in that bad of shape, considering it was about ten years old. But that's because it's never been run much. According to the manager who has been there since it was installed.

    Short of installing a whole new system, which the property owner wasn't willing to buy into since the last time they did that they didn't get any value for their bucks. I broke the repairs into several portions.

    So anyway, I recovered 32 pounds of who knows what, pulled a good evacuation, then recharged with 25 pounds of R-22 . . .

    And everything worked. LOL

    I was seriously not sure if it was or not. But I did my due diligence on the initial visit, crunched all of the appropriate numbers, did the calculations [since I don't have digital gauges] [the math took me like what, twelve and a half seconds, LOL], looked at the fans and blowers [no apparent restrictions], etc.

    Didn't even change the driers. Because there was no apparent reason to. And because of the way Trane built a two drier check valve arraignment ten years or whatever ago.

    After recharging, everything was perfect.

    Still don't have a clue what was in that system, but it's all in a recovery bottle now.
    Have you considered that the unit was simply overcharged - By about 7lbs?

    Sent from my SCH-I545 using Tapatalk

  4. #3
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    why would there be major bubbles in the sight glass then?

    You'd think that 50*F subcooling should clear the sight glass.


    Quote Originally Posted by shellkamp View Post
    Have you considered that the unit was simply overcharged - By about 7lbs?

    Sent from my SCH-I545 using Tapatalk

  5. #4
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    Quote Originally Posted by BBeerme View Post
    why would there be major bubbles in the sight glass then?

    You'd think that 50*F subcooling should clear the sight glass.
    I guess I missed that part.

    Sent from my SCH-I545 using Tapatalk

  6. #5
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    It is amazing how well it works sometimes when you recover what ever crap ends up in a refrigerant system and weigh in virgin refrigerant.
    UA Proud

    "Phfft! Facts. You can use them to prove anything." Homer Simpson

  7. #6
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    Just to be clear, being a split system, there was no weigh in charge. I just charged to a clear sight glass.

    Oh, and just for fun, this job did have another twist. Pretty sure not related to the temp / pressure problem thingy.

    So here goes. Someone installed a solenoid in the liquid line. On a heat pump split system. Didn't even really care how they wired it when I did the initial check out. Because anyone with a brain would know why it chattered in the off cycle of the heat mode.

    Removed that solenoid as part of my work today.

    100% positive that solenoid had nothing to do with the whacked out pressures. Nice that it was a rising stem solenoid. But no. Anyone who has dealt with a pump down system . . . . Well, you get the point.


    Quote Originally Posted by buttwheat View Post
    It is amazing how well it works sometimes when you recover what ever crap ends up in a refrigerant system and weigh in virgin refrigerant.

  8. #7
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    Vulcan blood.

  9. #8
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    Trane uses that two filter setup with the check valves in lieu of a biflow filter.
    I also would expect the condensing unit to have paper work stating the holding charge. Which still needs the installer to add additional refrigerant for extra line set length.

  10. #9
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    You expect the installer to leave paperwork? Huh.

  11. #10
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    Quote Originally Posted by BBeerme View Post
    You expect the installer to leave paperwork? Huh.
    Nope, but I might suspect rundawg would have it.

  12. #11
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    You think Rundawg could tell us what type of Vulcan blood that unit was charged with?

    I just charged to a clear sight glass. Not sure what I'd do with any paperwork.


    Quote Originally Posted by VTP99 View Post
    Nope, but I would suspect rundawg would have it.

  13. #12
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    Did you charge it in heat or cool mode?

  14. #13
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    Initial charging was in heat mode to avoid freezing the tenants. Final charging was in cool mode to a clear sight glass. Switch back to heat to verify clear sight glass and decent pressures.

    Back to cool to verify operations. Then back to heat.


    Quote Originally Posted by VTP99 View Post
    Did you charge it in heat or cool mode?

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