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Freon replacement

Discussion in 'HVAC' started by Capt Fred, Mar 6, 2018.

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  1. Capt Ralph

    Capt Ralph Senior Member

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    I'm not trying to be a hard but,,, but real shops have lots of rules and laws that keep us from experminting. I'm always open to learn of short cuts that may help others beyond my shops restrictions.
    Yes, please keep all up.
  2. Capt J

    Capt J Senior Member

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    See if you can find any oil residue anywhere. If all of the Freon leaked out, you should feel the oil around where the leak is.
  3. Capt Ralph

    Capt Ralph Senior Member

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    In my old days of experimenting, I thought of this. I even dusted joints with talc. Some leaks were not found this way. Some leaks do not mean the oil is coming out with it.

    Just today I did a compressor change out ( I'd swore never to do again). Nitrogen keep loosing pressure with test charge. F M.
    Good ole liquid soap proved the glands at the service valves were leaking and not my new silver joints. In today's wind (weather) the sniffer would of been worthless dock side.
    More old school; nothing beats a lil brush and liquid soap. I CAN legalley pass that on.
  4. Capt Fred

    Capt Fred Senior Member

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    All good info, thanks again. The Johnsen's Freeze 12 arrives tomorrow and the sniffer on Monday, should have some results mid next week.
  5. Captain Zemo

    Captain Zemo Senior Member

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    Any updates?
  6. Capt Fred

    Capt Fred Senior Member

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    I determined that the freezer had some Freon still in the system. I added about 3/4 of a can of freeze 12. The site glass shows no bubbles and the system is cooling and cycling. I could not identify any leaks. The thermostat was set to 25 F but only achieved 38 F. Next time on the boat will lower the thermostat to see if I can achieve freezing temperatures. Fred
  7. wdrzal

    wdrzal Senior Member

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    Under Charged won't cool, may freeze the evaporator. Over charged won't cool either, the suction pressure would be too high,( temperature moves with pressure) evaporator to warm. Consult a P/T (pressure/temperature) chart for R-12. Your problem now is you have a unknown ratio of R-12 & Freeze 12 so no accurate P/T chart is available,. Just right....well, is just right. The charge is critical, sometimes to 1/10 of a ounce. You can play with the low side suction pressure to tune. If you can let unit stabilize for 5 minutes , then get a low side suction pressure and post it, I may be able to give you some more help.
  8. Capt Fred

    Capt Fred Senior Member

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    Wdrzal: I lowered the thermostat and got the temp in the freezer box down to 10 degrees F. I was satisfied with that data point so I adjusted the thermostat 32 degrees F. The suction side pressure is 2.5 psi. The freezer appears to be operating ok but the site glass appears to be full of liquid even when the freezer has not been running for a while, is this normal? The site glass is located just above the top of the compressor / condenser housing.
  9. wdrzal

    wdrzal Senior Member

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    A full sight glass looks exactly like a empty one (when system is off and refrigerant is in a gaseous state). Somewhere on the case (not the compressor) you'll find the refrigerant( R12) and exact charge listed.
    Last edited: Apr 13, 2018
  10. Beau

    Beau Senior Member

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    Do I have a sight glass on my 50 post cockpit freezer?
  11. Capt Fred

    Capt Fred Senior Member

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    The tag on the box says refrigerant 12, charge 12 oz, tested at 150 psi and good for range of 10 to -10 degrees F.
  12. wdrzal

    wdrzal Senior Member

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    Most small appliances don't have access ports, let alone sight glasses. you would have to look. It would be after the condenser and before the metering device on the liquid line.
  13. wdrzal

    wdrzal Senior Member

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    Just want to point out to everyone the 8 oz. is by weight not fluid volume.
  14. Capt Ralph

    Capt Ralph Senior Member

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    Sight glass and Schrader (service) valves went away after mid life R12 units.