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Headmaster charging

Discussion in 'Refrigeration' started by Texas-Tech, Jul 15, 2012.

  1. Texas-Tech

    Texas-Tech stranger*

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    Had a walkin freezer last week that lost it's compressor, small hermetic. I c/o compressor and fd and recharged. I am under the impression your to add refer till the sight glass clears? When it was done I had head pressure of almost 400psi. I know that's way outa range for 404a and I removed enough to get to 300. Could the headmaster be bad?
  2. Bender

    Bender Promoted to Regional Turd Polisher

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    What was your ambient???
  3. crackertech

    crackertech assholiness

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    And box temp?
  4. Texas-Tech

    Texas-Tech stranger*

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    About 79°
  5. Texas-Tech

    Texas-Tech stranger*

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    box was at 35°
  6. Bender

    Bender Promoted to Regional Turd Polisher

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    I don't trust a sight glass until my box is down around operating temps.....

    Was your condenser coil clean? (I've seen quite a few that look clean on the outside but are letting air through)
  7. Texas-Tech

    Texas-Tech stranger*

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    First thing I did was wash it off. Appeared to be clean afterward. My sh outside at the compressor was like 50° also so I went back 2 days later and c/o txv. Then my sh was 17° it was running at 29 & 340psig and the box was at 7 so I left it there.

    Wouldn't you know that sometime after I left the sob shut down on head pressure and no one caught it till the next morning. Man they were pissed.
  8. jpsmith1cm

    jpsmith1cm Professional Un-thawer

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    400# is way out of line, expecially with a lower ambient like you had.

    http://sporlanonline.com/90-30-1.pdf Here is Sporlan's charging guidelines for systems with low ambient control valves like headmasters.

    Since it was a hermetic, I *assume* that you have to recover the entire charge and pulled a vacuum afterwards. Any chance of non-condensibles in the system?

    Another thing to look at would be a cracked or broken dip tube in the receiver. That'll kick your butt sometimes. Torch it and see where the actual level is while watching the sightglass.
  9. Texas-Tech

    Texas-Tech stranger*

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    I recovered 10 lbs, and the vac was good. The rec should be full correct
  10. Y7turbo

    Y7turbo New Member

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    When the head pressure was real high, did you notice if the condenser coil was warm or not?
  11. Texas-Tech

    Texas-Tech stranger*

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    Not as far as touching it but I did notice the discharge air didn't seem to indicate excessive heat load. I did feel the rec and it was hot
  12. Y7turbo

    Y7turbo New Member

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    If your pressures are real high, but your condenser isnt hot, it would indicate the headmaster bypassing the coil when it shouldn't be.

    Even if it was overcharged, during high head pressures the headmaster should have the hot gas port closed and full flow should be going through the condenser so the coil should be hot.
  13. Texas-Tech

    Texas-Tech stranger*

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    Thanks for the info
  14. frozensolid

    frozensolid Psychologist's Dream

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    Why would you even need a head master in Texas?
  15. Texas-Tech

    Texas-Tech stranger*

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    You tell me
  16. frozensolid

    frozensolid Psychologist's Dream

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    I can't think of any.
  17. Y7turbo

    Y7turbo New Member

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    I think they go below 70 degrees once in every 10 years. :D
  18. Texas-Tech

    Texas-Tech stranger*

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    I think the condenser was made by yankees:cheers:
  19. frozensolid

    frozensolid Psychologist's Dream

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    My bad. :)
  20. crackertech

    crackertech assholiness

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    We have em down here.

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