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rheem capacitor question

I have a 4.5 tun unit Rapm-056jez and it has a two capacitor setup with a relay the one capacitor I cant find is a 70 uf 6% 370 vac the model number is 43-101666-29 which has been replaced with 43-251136-17 but its half the size. the second capacitor I the unit has I found and it was a direct match and its a 88-106 mfd 330 vac model number 43-17075-04. should I be concerned that 43-101666-29 is have the size? or should I look for alternatives? I want to have backups just in case they fail any help would be greatly appreciated.


  • Jamie Hall
    Jamie Hall Member Posts: 22,050
    You should try to match the 70 uf cap. more closely. They don't have to be exact, but they do have to be close. You can go to a higher voltage rating, but not lower. Grainger has 70/370 caps in stock.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 14,455
    Don't be concerned about the physical size that means nothing.

    You can safely use any capacitor rated 70uf at 370volts or 440 volts. Especially if the capacitors you are replacing is older. The newer models are sometimes smaller
    HVACNUT Member Posts: 5,448
    If you're referring to the factory hard start cap/relay then you really should replace it with OEM parts if you're keeping the relay in the circuit. If you cant locate the parts you can do a little rewiring and install a Super Boost hard start capacitor without the relay.
  • pecmsg
    pecmsg Member Posts: 4,373
    Stick with the factory 5-2-1 start kit.

    External Overload (if so equipped)
    Start Cap
    Run Cap all at the same time!
  • eugd
    eugd Member Posts: 71
    thanks so much for all your input for some reason I never got the alerts that anyone answered my questions, I managed to find the exact model son all the parts except the external overload where is that located? and how does the part look like. I will check the manual later today to see if my unit has it its about 5 years old.
    EBEBRATT-Ed Member Posts: 14,455
    External overload if you have one is probably in the compressor terminal box
  • eugd
    eugd Member Posts: 71
    will check in the morning
  • HomerJSmith
    HomerJSmith Member Posts: 2,306
    A capacitor physical size is determined to a great extent by the insulation barrier. As thinner insulation is used the capacitor size diminishes. It's the rating that counts. You should try for the same rating as the original. Voltage is most crucial, you can go higher but not lower. Farads should be the same, a little variation higher is ok.
  • pecmsg
    pecmsg Member Posts: 4,373
    Yes a 450Vac can be used but the MF rating must be the same as the motor manufacturer specs.