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  1. #1
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
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    107

    convert R12 to hot shot with r134a comp?

    Long story short, I got a call: A small walk-in cooler no cooling. Trouble shoot it. the compressor didn't start. the start and run winding are 11 ohms,3 ohms and r to s total 14 ohms. it pull 32 amps which match the LRA on the nameplate then circuit opened by the Klixon overload. Checked capacitor,it's 140uf, (its range should be 145uf to 175 uf.)
    It's single phase,1/3 hp,capacitor start,induction run tecumseh compressor. It's nameplate marked with R134a,but someone made a note " R414" on it (don't know R414a or R414b hot shot). The comp was changed half year ago by somebody else. the walk in is more than 20 years and it might be a R-12 system before(info offered by the owner)
    My questions are
    1.anyone has any good method to check the current relay at this kind of situation?
    2.if the guy didn't flush the system, coverted the R12 to hot shot with a R134a comp.will it be damage?( if the old r12 comp didn't burnt out before)

  2. #2
    Join Date
    Sep 2011
    Location
    Augusta, ME
    Posts
    76
    to test the current relay couldnt you use a clamp on ammeter and measure amperage thru the start cap. As far as the refrigerants mixing I believe hot shot is compatible with R-12 and 134a

  3. #3
    Join Date
    Nov 2009
    Posts
    385
    There are a lot of variables and unknowns.

    What I would do for my customer at this point is reclaim the gas, flush the system, replace the compressor, and charge it with 134a. Insure proper superheat after starting it.
    "Don't wish it were easier, wish you were better"

  4. #4
    Join Date
    Dec 2010
    Location
    Woodbridge Twp, NJ
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    1,308
    Hot Shot (R-414b) is an HCFC and uses AB, R-134a uses POE.

    If he didnt flush the old oil out and put in AB, there may be an issue with oil miscability and having it travel around the system and ultimately back to the compressor.

    Sounds like a hack shack repair to me.
    Every customer you take for granted today will be someone else's tomorrow.

  5. #5
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
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    107
    Quote Originally Posted by sgagne199 View Post
    to test the current relay couldnt you use a clamp on ammeter and measure amperage thru the start cap. As far as the refrigerants mixing I believe hot shot is compatible with R-12 and 134a
    Thanks, i would try to test it this way.
    About hot shot,what if both type of oil with hot shot in one system,and it still work?

  6. #6
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
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    107
    Quote Originally Posted by thefreezerguy View Post
    There are a lot of variables and unknowns.

    What I would do for my customer at this point is reclaim the gas, flush the system, replace the compressor, and charge it with 134a. Insure proper superheat after starting it.
    Thanks.

  7. #7
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
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    107
    Quote Originally Posted by DLZ Dan View Post
    Hot Shot (R-414b) is an HCFC and uses AB, R-134a uses POE.

    If he didnt flush the old oil out and put in AB, there may be an issue with oil miscability and having it travel around the system and ultimately back to the compressor.

    Sounds like a hack shack repair to me.
    Thanks.
    The owner didn't see the guy doing it. I am thinking if both oil in the system with hot shot, is it the reason the comp get stuck after 6 months.

  8. #8
    Join Date
    Oct 2011
    Location
    Chicagoland Area
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    4,642
    I would use 414b to replace R12 and any conversions. 134a pump requires POE oil and I would stick with 134a.
    I don't know if things have changed ( if they have please enlighten me)but Copeland doesn't reccomend 414b at all for any of their pumps.
    Officially, Down for the count

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  9. #9
    Join Date
    Apr 2002
    Location
    Dallas, TX
    Posts
    2,987
    You'll most likely be successful with thefreezerguy's approach.

    If you prefer Hot Shot or one of the other R-12 service replacement refrigerants, get an R-12 compressor, e.g., AEA4440AXA if you currently have a high temp 1/3 hp compressor
    If the only tool you have is a hammer, you tend to see every problem as a nail. Abraham Maslow

  10. #10
    Join Date
    Dec 2011
    Location
    Michigan
    Posts
    119
    to test the relay I would recommend using a compressor analyzer. as far as the refrigerant issues I hate dealing with conversions done by others because you have know idea if it was done right. If it was originally a R-12 compressor I would drain the oil replace and charge with R-409. 409 works very well in R-12 systems. We put it right on top of 12.

    Good luck

  11. #11
    Join Date
    Jul 2009
    Location
    Northern area between Alantic and Pacific
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    107
    Update:Flushed the system twice with flush kit and nitrogen. Ordered the same type of r134a comp and replaced it. Changed the filter dryer, added a sight glass.Charged it with R134a. System worked good.
    Thanks guys for your good tips.

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