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  1. #1
    Join Date
    Jan 2011
    Posts
    135

    annoying compressor problem

    I have a client cooler medium temp r-12 2 door reach in with a top display case
    Its got a 1/3 hp aea4440axa tecumseh compressor in it, I replaced the compressor 9 months ago and the system was cooling good. I than got a call out of the blue saying the thing wasn't cooling, found compressor extremely hot, cooled down unit and tried to restart, sometimes it would fire up, others it did nothing, changed all the start components just to make sure they were all good, checked cap, (ok) I replaced the compressor with exact same, started it up, system cooled down for a day or two, than was short cycling off temp/press switch, settings were off a little due to new r-401a being retrofitted. Adjusted and got call day later saying unit not working again, found compressor trying to start but shutting off even before suction would start to drop, it would try to start for 2-3 seconds of rattling and shaking, than kick on overload, would draw system total amps of 7.4, top of compressor hot, lra on comp is 33.

    I let it sit all day and cool, came back and compressor is short cycling every 2-3 seconds again doing the shaking again, system ran for 10 min cooling decent, now its doing the same thing the other one was. Starting for split second than shutting off on overload, resetting and repeating the same results everytime. What do i do now.

  2. #2
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,619
    Quote Originally Posted by zuke19 View Post
    I have a client cooler medium temp r-12 2 door reach in with a top display case
    Its got a 1/3 hp aea4440axa tecumseh compressor in it, I replaced the compressor 9 months ago and the system was cooling good. I than got a call out of the blue saying the thing wasn't cooling, found compressor extremely hot, cooled down unit and tried to restart, sometimes it would fire up, others it did nothing, changed all the start components just to make sure they were all good, checked cap, (ok) I replaced the compressor with exact same, started it up, system cooled down for a day or two, than was short cycling off temp/press switch, settings were off a little due to new r-401a being retrofitted. Adjusted and got call day later saying unit not working again, found compressor trying to start but shutting off even before suction would start to drop, it would try to start for 2-3 seconds of rattling and shaking, than kick on overload, would draw system total amps of 7.4, top of compressor hot, lra on comp is 33.


    I let it sit all day and cool, came back and compressor is short cycling every 2-3 seconds again doing the shaking again, system ran for 10 min cooling decent, now its doing the same thing the other one was. Starting for split second than shutting off on overload, resetting and repeating the same results everytime. What do i do now.
    I'd be willing to bet the capacity on the unit has changed. I went thru a similar issue with a unit that was converted from R12 ot 134a. Went from an 1/3hp R12 to a 1/3 134a and had similar results. Spoke to tech suppt and got all the answers I needed. Changed condensing unit to 1/2hp and never been back.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  3. #3
    Join Date
    Oct 2008
    Location
    Cleveland, Ohio
    Posts
    27
    is it hard wired or plug-in? Check your power supply. Is it the original pressure control and is it working properly? Quit using 401 its too dam expensive use 134a. The unit short cycling is killing your compressor you need another one. Also if its cap tube have you changed it along with your drier?

  4. #4
    Join Date
    Oct 2008
    Location
    Cleveland, Ohio
    Posts
    27
    your capacity with 12 is 4100 btu and your capacity with 134a is 3960 btu

  5. #5
    Join Date
    Jan 2011
    Posts
    135
    Quote Originally Posted by evilsanta View Post
    is it hard wired or plug-in? Check your power supply. Is it the original pressure control and is it working properly? Quit using 401 its too dam expensive use 134a. The unit short cycling is killing your compressor you need another one. Also if its cap tube have you changed it along with your drier?
    Yes but how much stuff am I going to have to replace to convert to 134 a, drier no biggie, txv, oil in compressor,it is hard wired, pressure control is working correctly, condenser fan keeps running and compressor is short cycling, outlet of press control wired in series with common of comp and one leg of cond fan, other leg of power wired to start relay, nothing changed capacity wise in past 2 years, he even had ice inside cooling it all down while I was fixing it so load was less,I got to be missing something

  6. #6
    Join Date
    Oct 2008
    Location
    Cleveland, Ohio
    Posts
    27
    You technically should change the oil. But in a 1/3 hp systems if you asked for a show hands on how many people actually change the oil when converting 12 to 134a the room will get pretty quiet. I think you may have an issue with your txv. Sounds like its shutting and it wont open until its really warm in the box again, but if the txv is ok you dont need to change it due to the t/p being pretty similar of 12 and 134a in med/high temp applications.

  7. #7
    Join Date
    Jul 2011
    Location
    Lehigh Valley, PA
    Posts
    447
    Little confused here. Are you using pressure control for temperature control or you using a T-stat? Possibly the pressure control switch cannot properly handle the current flow.

    Shouldn't your neutral leg of the 115vac be wired to the Run on the relay? You have it on the Start.

  8. #8
    Join Date
    Oct 2011
    Location
    Chicagoland Area
    Posts
    4,619
    I'm going to guess it will only start when pressures are equalized. It can't overcome the pressure difference.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  9. #9
    Join Date
    Jul 2011
    Location
    Lehigh Valley, PA
    Posts
    447
    I'd jump out the overload safety too. I've seem them go bad after frequent trips.

  10. #10
    Join Date
    Jan 2011
    Posts
    135
    tried that on the first one

  11. #11
    Join Date
    Jan 2011
    Posts
    135
    txv was replaced recently and this thing was working fine, than all of a sudden this compressor issue came up, was working 3 years with the same size compressor
    Quote Originally Posted by evilsanta View Post
    You technically should change the oil. But in a 1/3 hp systems if you asked for a show hands on how many people actually change the oil when converting 12 to 134a the room will get pretty quiet. I think you may have an issue with your txv. Sounds like its shutting and it wont open until its really warm in the box again, but if the txv is ok you dont need to change it due to the t/p being pretty similar of 12 and 134a in med/high temp applications.

  12. #12
    Join Date
    Jan 2011
    Posts
    135
    tried that on the first one before i changed it because it was tripping so fast
    Quote Originally Posted by Capz View Post
    I'd jump out the overload safety too. I've seem them go bad after frequent trips.

  13. #13
    Join Date
    Jan 2011
    Posts
    135
    kind of only starts when it is cold its not drawing crazy amps to start, its like it won't kick before overload trips
    Quote Originally Posted by 2sac View Post
    I'm going to guess it will only start when pressures are equalized. It can't overcome the pressure difference.

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