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  1. #1
    Join Date
    Sep 2011
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    12

    A Rheem Silver Anniversary

    That's right - I'm working on a 25+ year old Rheem PCA-030. Does anyone have any of the old installation manuals for this. Near as I can tell this was a package that was re-worked in the field (no excess lineset coiled in the attic). It does have an accumlator, and is an old capilary (no txv) system. Evaporator coil looks new and outdoor coil is clean too. Airflow is good and hard-line ducts are actually insulated! System has a very slow leak at the accumlator output stub where they tend to rust out. Compressor is a Copeland CRG1-250-PVF with a failed crankcase heater. I'm trying to use the original charge table (superheat) from the condensor cover, but it doesnt make any sense at all. I'm hoping someone here with a lot more experience than me can help me sort it out. I suspect the system is overcharged, but the table seems to say it's undercharged. So here's some numbers:

    Outdoor ambient: 70
    Static preasure: 125 (its R22 of course)
    In cool mode:
    Suction side service port entering condensor: 57psig
    Suction side temperature between acc and cpr: 38f
    accumlator and suction lines are all happy sweating.
    18f drop across evaporator

    In Heat mode:
    355psig measured at evaporator
    36f rise across evaporator (78f at return 114f at supply)

    I dont work on these old systems and its unusual for me to see head preasures this high - but I'm willing the accept it might be near normal for this old girl.

    The stumper is the Rheem superheat chart says for 70f od at 57psig I should have a suction line temp of 74f! The chart instructions say anything to the left of that (which I am of course as the suction line is about 38f and sweating), says I'm low on charge.

    Can you old timers chime in here and teach a young buck a thing or two? How on earth can this old Rheem charge chart be right? What am I doing wrong?

    Thanks.

  2. #2
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
    Posts
    7,622
    what's the head psi in cooling?


    what does that OD coil look like?





    haven't found charging chart
    Last edited by dandyme; 09-03-2011 at 09:01 PM.
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  3. #3
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,411
    What is the complaint? What is the head pressure in cooling mode? Static pressure is 125? The thing that bothers me is that you said it's a package unit that was re-worked in the field as far as you can tell. Not exactly sure what that means. It's either a package unit or it's not. Pretty basic to figure out.
    I like DIY'ers. They pay better to fix.

  4. #4
    Join Date
    Sep 2011
    Posts
    12
    Quote Originally Posted by dandyme View Post
    what's the head psi in cooling?

    what does that OD coil look like?

    haven't found charging chart
    Cant measure head psi at condensor - they never installed a service port on the high side. They did install one at the evaporator and head psi there is around 195psi in cooling.

    It's a standard Rheem low-profile square coil. The coil has held up pretty well and is very clean. Some rusting out at the bottom but overall is in pretty good shape.


    Thank you for checking...

  5. #5
    Join Date
    Sep 2011
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    12
    Quote Originally Posted by bmathews View Post
    What is the complaint? What is the head pressure in cooling mode? Static pressure is 125? The thing that bothers me is that you said it's a package unit that was re-worked in the field as far as you can tell. Not exactly sure what that means. It's either a package unit or it's not. Pretty basic to figure out.
    Good question. Seems the owner had the system checked by another contractor and they said the system was leaking but overcharged - which made no sense to me. The owner asked me to check it out. I did find a small leak (already mentioned) but cant make sense of the rheem charge chart from the condensor cover. I forgot to mention in the original post that the 1980's label showing the model, serial and specs is long gone - so no idea of the factory charge or anything else. The compressor is pulling 12.5 amps and the compressor is rated at FLA of 75.8. No RLA rating given. Using the divide by 6 rule for 1ph 230v gives me a RLA of about 12.5 - which suggests the compressor is running 100%RLA.

    Thank you for any suggestions you might have.

  6. #6
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
    Posts
    7,622
    comp RLA 19.9

    LRA 85.0


    ODF 1.0

    min circuit 26.0

    max circuit 40.0


    has the qiuck connect been cut out or was line set installed backwards?
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  7. #7
    Join Date
    Sep 2011
    Posts
    12
    Quote Originally Posted by dandyme View Post
    comp RLA 19.9
    LRA 85.0
    ODF 1.0
    min circuit 26.0
    max circuit 40.0

    has the qiuck connect been cut out or was line set installed backwards?

    thanks for the data. Compressor tag (copeland) say L.R.A 75.8, but I like your numbers better. You might be on to something. I'll bet they installed the lineset backwards and then realized that afterwords so they added a Low side service port at the condensor. Kinda nice having service ports at the evaporator to check sub-cooling though. It's pulling 12.5 amps now.

    Any thoughts on the 355 psi? Could it be grossly overcharged? The HPC hasnt tripped (440 I think).

  8. #8
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
    Posts
    7,622
    the info came from rheemote, it's what would be on the label
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  9. #9
    Join Date
    Sep 2011
    Posts
    12
    Quote Originally Posted by bmathews View Post
    What is the complaint? What is the head pressure in cooling mode? Static pressure is 125? The thing that bothers me is that you said it's a package unit that was re-worked in the field as far as you can tell. Not exactly sure what that means. It's either a package unit or it's not. Pretty basic to figure out.
    Sorry, I didn't mean a "package", but rather a package of a split heat pump with a pre-made lineset. It looks like the lineset was cut off after the QC's and then brazed back together again. Vapor pressure of R22 at 70f is 125psig - that's what I meant by "static preassure", not static pressure in ducts.

    The system is working, but appears to be overcharged.

    Thanks for the input.

  10. #10
    Join Date
    Sep 2011
    Posts
    12
    This jobs done. I thought I'd close this thread with final results and what I learned. First, on these old splits, Rheem uses the smallest amount of refigerent possible - which is why you see high superheat on the charging charts. I used the iwbX3-80-odb formula and calculated a target SH of 29. After recovering several ounces I reached a sh of 26 - close enough for me. My head pressure droped from 355 to nice 275psig in heating. So I'm happy with the final charge - and YES, it was overcharged! Thanks to everyone that offered a useful suggestion. And to the other trolls that lurk here I can only say - go get a life!

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