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  1. #1
    Join Date
    Feb 2010
    Location
    IL
    Posts
    123

    Run cap going bad 3 in 6 weeks.

    Hey all,

    Had a call today a Trane XL12 4 ton split system from 1/2001. Dont have model or serial handy. Anyways about a month ago a tech went out and did a C&C and found run capacitor low on MFD's. Cap is a 50/7.5 440VAC. He changed it out only had a universal cap for that size. Cap work and unit ran for 3 weeks.

    Another tech got called back out, cap bad again. Figured maybe fault universal cap. Replaced again with another univeral. Worked for 2 1/2 week.

    I got the call today and sure enough cap was bad again. So I replaced again mean while I checked amp draw on the compressor. RLA 16.0, compressor running at 10A. Pressures were good, 10SC and 18SH TXV system. Condenser fan RLA 1.9A, fan running 1.6A.. Check voltage of each leg out of contactor 248VAC. 123VAC and 125VAC on each leg to ground.

    Any idea what could be causing cap to blow? All connections tight... Thinking power issue supplying unit, customer has another unit the same and it has had zero issues. Ordered an OEM cap to try also will put it in tomorrow.

    Any ideas?

    PS, Cap is a motor-mate universal

  2. #2
    newoldtech's Avatar
    newoldtech is offline ARP Committee/Professional Member
    Join Date
    Dec 2005
    Posts
    3,931
    Could be the motor or the compressor is going bad. I would put in two separate caps and see what happens.

  3. #3
    Join Date
    Aug 2011
    Location
    Goose Creek ,SC
    Posts
    252
    define universal is it like the turbo 200 caps a multi mfd? the right cap is the right cap as long as he got the mfd and the voltage right you cant do a 370 whert a 440 went if it is universal that should not matter. Sounds like crappy caps. there may be a reason it is eating caps. I had a bunch do that to me one summer. I switched brands and OK. try the two cap thing I just did that too a while back .
    "I just think things should work properly"
    Freon is a brand name-word


  4. #4
    Join Date
    Sep 2010
    Location
    Western, MO
    Posts
    871
    Are you sure the first tech read the cap right and put the correct cap in it.

    If I'm out on a call back for start or cap, i always recheck what I put in it. I have had a case or two where the last tech put the wrong rated part on it and I, being hot and tired, just replaced what was on it.

    jim
    Common sense isn't very common anymore.

  5. #5
    Join Date
    Feb 2010
    Location
    IL
    Posts
    123
    Universal cap is rated for 370 or 440. So that's fine. Yes it's a multi mfd like the turbo 200. I called Trane a verified cap size before I installed. Should be a 50/7.5 which what was in there. So everything should be fine there. Maybe try to 2 cap deal so I can see what one blows if it does.

  6. #6
    Join Date
    Apr 2011
    Location
    michigan
    Posts
    170
    I have had the exact same problems with those caps, motor-mate universal caps are JUNK! I have replaced every single one I have ever used in a year or less, I had 2 seperate units that they would fail in 3-4 weeks. Did the same checks you did, checked amps, voltage, ohmed out motors, checked mfd of new caps, I was the only tech on these calls as I am the owner of my business and have no employees as of yet. I replaced all of the universal ones with OEM fixed value caps and have not been back on any of these since and they are all still running, I have checked back with the customers to be sure the problem was resolved. I have e-mailed motor mate about this and they never responded, caps labeled with a 5 yr warranty, I will never use this brand again, have a couple left I use only if I dont have the OEM cap, then I just put the universal on over the weekend or until I get the OEM cap. I noticed on the universal caps the temp rating is 70c while the OEM fixed style are rated at 80c or 90c for the temp, not sure if it makes the difference, just know that brand I have had nothing but problems with. Good luck!!

  7. #7
    Join Date
    Jul 2012
    Location
    sanger texas
    Posts
    21
    what is the starting amp on the compressor , might need to add start kit if not i would suggest checking resistance in compressor windings might be weak

  8. #8
    Join Date
    Jul 2012
    Location
    NE KS
    Posts
    41
    cleared

  9. #9
    Join Date
    Nov 2011
    Location
    Phoenix,AZ
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    289
    I have heard bad things about the one size fits all caps I personally don't use them

  10. #10
    Join Date
    Jan 2012
    Location
    indy
    Posts
    471
    Quote Originally Posted by newoldtech View Post
    Could be the motor or the compressor is going bad. I would put in two separate caps and see what happens.
    GOOD IDEA

  11. #11
    Join Date
    Sep 2010
    Location
    Western, MO
    Posts
    871
    Quote Originally Posted by KevinAdv View Post
    I have heard bad things about the one size fits all caps I personally don't use them
    I can't say it won't happen, but at this point I have never replaced a Turbo 200.

    jim
    Common sense isn't very common anymore.

  12. #12
    Join Date
    May 2008
    Location
    Myrtle Creek. Oregon
    Posts
    182
    I have had sitiuations like this. after 3 caps I found that the compressor terminals were dirty. cleaned terminals crimped on new stakons, after that no more problems. ckeck for tight connections at the comp.
    a stupid question is a question you wont to ask, but don't

  13. #13
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Use better run capacitors.

    AmRad USA, or Mars "Made in Mexico" capacitors only.

    Pretty much all of the Chinese made capacitors are junk.
    If more government is the answer, then it's a really stupid question.

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