Page 1 of 3 123 LastLast
Results 1 to 13 of 33

Thread: Cap question

  1. #1
    Join Date
    Oct 2007
    Location
    Austin Texas
    Posts
    1,990
    Post Likes

    Cap question

    Has anybody piggybacked a low performing cap to increase its rating to get it by temporarily.
    Nemo me impune lacessit.

    How much blood do I have to bathe in to get clean?

    Don't look down on anyone unless you're helping them up.

  2. #2
    Join Date
    Mar 2019
    Posts
    22
    Post Likes
    No I’ve piggybacked caps to get the proper size when I didn’t have the right one . I have also added a slightly higher mfd rated cap on to get a customer by until I could get the right one . In theory , say that you needed a 40 mfd , the cap that was on the unit was reading 30 you could wire in a 10 to make it a 40 I don’t see how that would be any different.


    Sent from my iPhone using Tapatalk

  3. Likes CEAS-AC-TECH liked this post.
  4. #3
    Join Date
    Jul 2019
    Location
    Oklahoma home its in the name
    Posts
    993
    Post Likes
    I usually just piggyback 2 new incorect size ones to get by temporarily. I it would probably work fine but i wouldn't do it.

    Sent from my rotary telephone using Tapatalk

  5. Likes CEAS-AC-TECH liked this post.
  6. #4
    Join Date
    Oct 2007
    Location
    Austin Texas
    Posts
    1,990
    Post Likes
    Thread Starter
    I don't feel so bad then. I didn't have a forty on board their cap was 33 out of forty. I threw in a 7.5 until tomorrow. Just wondered if anyone else had to do this.
    Nemo me impune lacessit.

    How much blood do I have to bathe in to get clean?

    Don't look down on anyone unless you're helping them up.

  7. #5
    Join Date
    Feb 2016
    Location
    Roanoke, VA
    Posts
    233
    Post Likes
    Capacitors are cheap. Why wouldn't you just have two of each of the most popular caps (so you don't run out that day) or get a turbo200?

  8. #6
    Join Date
    Mar 2018
    Location
    Chico, Ca #StateofJefferson
    Posts
    1,664
    Post Likes
    If the compressor wasn't running with the cap as is and I couldn't jump a couple new ones together to make 40, only then would I do that. The part is failing, it might not make it until tomorrow, but if it all you got it's all you've got!

  9. #7
    Join Date
    Apr 2006
    Location
    Houston, Texas
    Posts
    30
    Post Likes
    Sometimes you gotta do what you gotta do to get someone by until you can do the right thing. It will work as long as the bad cap doesn't get worse.

  10. #8
    Join Date
    Jul 2011
    Location
    DFW, TX.
    Posts
    1,481
    Post Likes
    Always check a cap under load. It'll give the most accurate reading.

    Sent from my LG-G710 using Tapatalk

  11. #9
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    32,121
    Post Likes
    When I have had to parallel two capacitors to make up the proper rating, I start with two brand new caps.

    I would not trust a failing capacitor to maintain that 30 out of 40 microfarads..... even for a week.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

    AOP Forum Rules:







  12. Likes CEAS-AC-TECH liked this post.
  13. #10
    Join Date
    Sep 2002
    Location
    Virginia
    Posts
    6,757
    Post Likes
    When I add 2 together ... I never go back

    They actually last wayyyyy longer

    In fact I was cleaning a evaporator coil at this house and it occurred to me , hmm , isnt this one of my ghetto units ?

    Went over to OD unit , pulled the cover .... holy crap , piggy caps still there 8 years later still rockin it

  14. #11
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    32,121
    Post Likes
    I have to maintain OEM approaches to the devices being used.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

    AOP Forum Rules:







  15. #12
    Join Date
    Jul 2018
    Posts
    14
    Post Likes
    I carry the right ones on my truck 2 to 80uF. But if you are going to piggy back two together, they should be close to the same rating-like two 20's or a 15&20 versus a 5&30. A good senior tech taught me that.

  16. #13
    Join Date
    Jul 2007
    Location
    Virginia
    Posts
    11,708
    Post Likes
    Quote Originally Posted by george3 View Post
    A good senior tech taught me that.
    Did he explain his reason for that?

    I can't think of any rational for it.
    Instead of learning the tricks of the trade, learn the trade.

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •