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  1. #1
    Join Date
    Apr 2011
    Location
    West of DFW
    Posts
    262

    Lubrication protection module?

    I found a walk in freezer not cooling (routine maintenance). I could feel the liquid solinoid valve was calling. Went to the remote condensing unit a Copeland Discus and found that the Penn 45( lubrication protection had tripped) this is the older mechanical pressure differential. I have to be honest I've never checked the oil pressure before, so I checked the PSID by using old set of gauges. My reading was at peak 68 PSIG. I also found that the contactor was pitted. I am replacing this contactor. Any reason to upgrade the Penn 45 with the electronic whatchamacallit ?

  2. #2
    Join Date
    Jun 2011
    Posts
    11
    what was your net oil pressure (pump pressure - suction pressure)? you may have issues with a plugged strainer if was tripped on the oil protection. I say, if the oil protection tripped, then it's working. I try to avoid replacing working parts.

  3. #3
    Join Date
    Mar 2011
    Location
    Edna Bay, Alaska Highest concentration of black bears in the US
    Posts
    623
    A bad contactor can cause the oil switch to open.

  4. #4
    Join Date
    Aug 2002
    Location
    Sacramento area
    Posts
    69

    Wink

    Keep in mind, the correct way to check net oil pressure is by checking oil pump discharge pressure and "Crankcase" pressure, which may be higher than "Suction" pressure if your compressor has blow-by. This fools a lot of guys because when they subtract the suction pressure from the oil pump discharge pressure, it may indicate correct net oil pressure, but that's not what the oil pressure control senses if it is correctly installed with the connection at the crankcase.

    If the compressor contactor has a contact that sticks closed, sending voltage to the heater inside the oil pressure control while the compressor is off, this means there is no oil pressure when the control "thinks" the compressor is running.
    I'm still learning this trade.

  5. #5
    Join Date
    May 2011
    Location
    Chas.,WV
    Posts
    30
    Finding a unit tripped out on "oil failure" has to be one of the least favorite things that we encounter. There are so many different reasons why the contol will trip out. Everything from an actual lack of lubricant to low refrigerant , iced coils, evap fans, plugged filter driers, and on and on which mostly do not repeat themselves in your presence.You stated the contacts were pitted. On a three phase system if the contactor makes and only single phase makes it to the compressor it will not start and will hopefully only trip on the protector. Meanwhile assuming the oil safety is wired correctly it will time out and open the circuit. The advantage of putting an electronic control on is that it is suitable for all voltages and will not require changing the resistor to match the control voltage to keep your time at the required 120 seconds.

  6. #6
    Join Date
    Feb 2006
    Location
    USA
    Posts
    4,381
    I witnessed one the other day go out in front of me .. im relatively new to the world of semis & initially I'm thinking clogged screen . . I've asked guys here & got good info .. although lol im still learning

  7. #7
    Join Date
    Feb 2008
    Location
    California
    Posts
    2,071
    Quote Originally Posted by blazey10 View Post
    Any reason to upgrade the Penn 45 with the electronic whatchamacallit ?
    no

  8. #8
    Join Date
    Mar 2011
    Location
    Texas
    Posts
    27
    Also it is good practice to check the oil level in the compressor before resetting the oil failure switch. It helps me narrow down the search and no to the upgrade.

  9. #9
    Join Date
    Apr 2005
    Location
    Central California
    Posts
    186
    Always be very careful when resetting an oil failure. If it has been tripped for a bit of time and the solenoid stays energized then guess what happens when you hit that reset..... All of a sudden you have an evaporator full of liquid refrigerant rushing it's way to the pricey compressor.

    The solenoid should de energize when a fault occurs but you would be surprised of how many systems are out there where the solenoid is mounted at the evAp on a totally separate circuit. Throttle the suction down before hitting that reset and check all pressures. In my experience the oil failure is rarely at fault. Check your cc heater, etc. And if you add oil don't forget that you may have to remove some once you get the system operating correctly. Too much oil can cause as many problems as not enough.

    The other day I ran across a 5h80 that had so much oil in it I couldn't touch the crankcase. The crank was beating the hell out of the oil and smashed up the brass pick up screen. 2 gallons too much in the case
    Only Chuck Norris can slam a revolving door

  10. #10
    Join Date
    May 2011
    Location
    Chas.,WV
    Posts
    30
    Two more benefits of the electronic would be the ease of routine testing and not having to worry about a stress fracture or something vibrating against the cap tubes wearing a hole, and causing loss of oil or refrigerant.

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