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  1. #40
    Join Date
    Sep 2002
    Posts
    12,567
    What it hot on the roof? Maybe the "oil level" you saw was half dissolved refrigerant. By the time you got back it had boiled off and lowered the apparent oil level?

    The CCH will only help prevent oil dilution in the off cycle. It cannot compensate for low operating SSH.

    PHM
    ------





    Quote Originally Posted by csmyn View Post
    The prints show two PE switches which bring on the cooling stages. I'm guessing that it's always been a 2 stage. The CCH died on me today, I checked the oil sight glass and the level was half way. I went to get a new CCH and when I returned the oil level was at the bottom of the sight glass. I thought this was odd because the machine was off the entire time I was there. Could the oil have returned to the compressor and filled the sight glass half way just before I got there if the building automation system started the unit?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  2. #41
    Join Date
    Nov 2008
    Location
    Maryland
    Posts
    65
    It was around 82 degrees before I left to go get the new heater. When I returned 1-1/2 hours later it was around 88 degrees outside.

  3. #42
    Join Date
    May 2010
    Posts
    232
    I am glad this was finally mentioned!!! Good call PHM. Also something to add, not knowing how much oil has been added over time I would assume that the refrigerant is "oil Saturated" not enabeling proper heat tranfer. Also is your DX coil before or after the chilled water coil? You need to verify that all the airside areas are correct.
    Quote Originally Posted by Poodle Head Mikey View Post
    What it hot on the roof? Maybe the "oil level" you saw was half dissolved refrigerant. By the time you got back it had boiled off and lowered the apparent oil level?

    The CCH will only help prevent oil dilution in the off cycle. It cannot compensate for low operating SSH.

    PHM
    ------

  4. #43
    Join Date
    Nov 2008
    Location
    Maryland
    Posts
    65
    DX coil is after the chilled water coil.

  5. #44
    Join Date
    Mar 2014
    Location
    Northern Vermont
    Posts
    63
    Now that we have found out it is 2 stage system and it sure does sound like the piping is not “right outa the book” and proper oil return is a problem.
    Someone must have made this a single stage system to help solve some of the oil return problem. Must be it got switched back to a 2 stage or there is some other control issue and now the oil return problem is back also. Find out where that problem is follow what PHM and others have said and you will have a system that stays running. I was told that in refrigeration piping before you go up you should always go down and this will help to get the oil back to the compressor.

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