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ncwolfpack

Will Wrong run capacitor cause damage to AC?

ncwolfpack
11 years ago

Our AC was not working and a service guy came fixed by replace run capacitor. After he replaced it the AC start to work but I notice my broken capacitor was 80/5 mfd V440. The new one he put in is 45/5 mfd V370. I called him but he said it doesn't matter since it's working now. I really worry about if there will be more damage to my AC since wrong size is in it now? Also, wondering how could a capacitor half the size would work.

Comments (33)

  • fluffybunnysui
    11 years ago

    The capacitor should be replaced with one of equal size and voltage...or greater voltage. You can go from a 370vac to a 440vac but not the other way. Are you sure he didn't piggyback 2 capacitors to make the 80mfd? Sometimes when we're out of a large capacitor, we will connect 2 capacitors together to get the proper value... like 2-40mfd's wired together will give you 80mfd.
    You might check.

    Hope this helps

  • mike_home
    11 years ago

    Are you sure the old capacitor was an 80/5 mfd size? That seems to a big size. How many tons is your condenser?

    A wrong size capacitor could cause the compressor to overheat and shorten its life, or not run at its peak efficiency. The lower voltage rating is also a problem. The life of the capacitor will be shortened.

  • ncwolfpack
    Original Author
    11 years ago

    mkie_home and fluffybunnysui thanks for reply.

    No, didn't piggyback 2 capacitors.

    Now, I am wondering if I really need 80/5 mfd capacitor in first place? Following is spec information on my compressor:

    Danfoss AC Compressor
    Refrigerant Type R-22
    Nominal HP 5
    BtuH 60,000
    Voltage 208/230
    Hz 60
    Phase 1
    Amps 28.8 RLA
    Run Capacitor MF/Volt 80 Start Cap. MFD/Volts 189-227

  • heatseeker
    11 years ago

    yes you need the right size cap within 5 %.

  • Joseph Farran
    6 years ago

    I have a 40/5. When I measure capaticance on a 40/5, the 40 is really 39 which is within spec -+6% for the compressor. Can I use a 45/5 if it measure say around 44?

  • weedmeister
    6 years ago

    5 year old thread.

    I think you're safe. The cap values don't have to be that close.

  • HU-902477819
    5 years ago

    Can I use a 35.5 instead of 30mf.mf.compacitor

  • PRO
    Austin Air Companie
    5 years ago

    It's always best to use proper value capacitor matched to the motor that it's attached to.

    An improperly sized capacitor attached to a motor can effect the life of that motor. However, that motor will not last forever anyway because there are bearings that will fail at some point. (seized bearing failure among others)

    Even 'IF' you do everything right, size the capacitor right to the motor it is attached to, the capacitor can become 'weak' over time. A weak capacitor will not have a proper rating that the motor it is attached to needs to run properly.

    In most circles they call this 'MAINTENANCE'. Everything in this world requires maintenance... even you. If you quit taking showers, what happens?

    From here we get into 'proper maintenance'. This means having to know actually what it is you're doing is right --- because everything else is wrong. There is risk in dealing with something that is wrong. (not looking both ways before crossing the street is an example)

    Applied to the take a shower mentality. If you take a shower everyday only using water and no soap... what is the result?

    Ok how many enemies did I make in posting these truths today? Raise your hands.

  • mike_home
    5 years ago

    Why not just buy the 30 Mfd capacitor and then not worry about it? They are available on Amazon for $12 and you can have delivered the next day.

  • HU-982950309
    4 years ago

    Hello, I have a Bryant AC unit model # 698BNX036000ABAA and I saw the compressor capacitor is bulging and I want to replace it. The current capacitor is 45 uF, 370VAC, 50/60 Hz but I cannot find out online if this is the correct specs for the capacitor or if someone installed the wrong capacitor for this unit and that is why it has gone bad.

  • mike_home
    4 years ago

    Here is a 45 µF 440VAC available on Amazon. You can substitute the higher voltage 440VAC for the 370VAC. In theory it should last longer since it is more tolerant to line voltage surges.

  • HU-982950309
    4 years ago

    Thank you so much!!! Do you happen to know if the 45 uF 370 VAC is the correct rating for the capacitor for this model? I'm wondering if whoever replaced the capacitor the last time didn't use the correct one.

  • fsq4cw
    4 years ago

    Just because you bought a ‘Run’ capacitor somewhere that ‘seems’ to have the right capacitance and voltage values doesn’t necessarily mean you’re in the clear. There are many numbers, codes and specs on a capacitor and it would be wise to understand what they all mean. Similar specs - within even the same brand - might not mean the same things completely, especially if the components are manufactured in different countries. This is why an understanding of everything written on a capacitor should be understood.


    Do you remember that high rise building in England (Grenfell Tower) that went up like a Roman candle with the loss of dozens of lives? It’s said that that fire started with a ‘defective fridge’.


    Do you think it possible that perhaps someone might have repaired a refrigerator with the wrong ‘type’ of capacitor? We’ll never know for sure but it’s not beyond the pale.


    Caveat Emptor!


    IMPO


    SR

  • mike_home
    4 years ago

    The only way to verify if 45 µF is the correct value is to check the schematic. I tried looking for the product data for your condenser but so far I have had no luck. Is there a circuit diagram pasted inside the condenser housing? That may indicate the correct value.

  • HU-396540681
    4 years ago

    i fitted a higher rating capacitor in a clothes dryer and it actually spun faster and it was nosier! The closer the better but not lesser, A/C needs no less than what a manufacturers requirements!

  • User
    4 years ago

    OEM Run capacitor seems to be a P291-4504RS. Rated at 45uF but 440 VAC. Looks like someone downrated your capacitor at some point. $20.39, found via Google search for that model and replacement parts.


    Please note this possible recall for your unit: https://www.hvacrecalls.com/files/2016/03/DSB05-0012.pdf

  • Chris Rajnarinesingh
    4 years ago

    How to connect a 40 and 15 mf capacitors to get 55


  • HU-178658043
    4 years ago

    In parallel

  • HU-448140298
    2 years ago

    Sometimes techs will throw any capacitor on unit just to get someone going, & for getting credit for

  • Kanth Kodidheti
    2 years ago

    My Ac capacitor 45/5 370v +-10 tolerance, can i replace with 45/5 370v +-6 tolerance? diffrent tolerance makes any issue?

  • mike_home
    2 years ago

    Yes you can. The tolerance specifies the high and low range of the capacitor's nominal values stated as a percentage. The smaller the tolerance rating the closer the high and low values will be to the nominal rating. Therefore a capacitor with a +/- 6% tolerance is better and costs more than one with a +/- 10% tolerance.

  • HU-360097586
    2 years ago

    I replaced a 45/5 capacitor with a 35/5 and something in the furnace smelled a bit like smoke and now the blower won't turn on anymore.

  • HU-103538682
    2 years ago

    My a/c guy put an 80/10mfd +-6% 440V capacitor but my compressor says specifically 70mfd and 440V on the label. Will this be an issue? My compressor seems of be heating up quickly.

  • mike_home
    2 years ago

    Are you sure he installed a dual 80/10 mfd capacitor in place of a 70 mfd single capacitor? You should always replace the capacitor with the value specified by the manufacturer. If this is the start capacitor, then an increase of 10 mfd (14% higher) may be acceptable. But if this is the run capacitor then it could cause an increase in current flow and cause the compressor to overheat. It is best you put in the proper value for long term life of the equipment.

  • HU-103538682
    2 years ago

    Thanks for quick response, Mike. It's a dual capacitor. The compressor seems to be heating up and after about 20-30 mins the breaker flips. Then when I turn breaker back on, the compressor hums but the fan doesn't start up.

  • mike_home
    2 years ago

    You need to call the tech back ASAP. The correct capacitor needs to be installed. I recommend you don’t run the AC until it is properly fixed.

  • sktn77a
    2 years ago

    If the breaker is tripping, you need to get him back asap.

  • Lee Hong Beng
    2 years ago
    last modified: 2 years ago

    Hi!

    Can I replace my ceiling fan capacitor of 1.6uf 500VAC with either 1.5uf 450VAC or 1.8uf 500VAC because I cannot find the same type online and the spare parts are not widely available?

    Thank You

    Lee Hong Beng

  • Jeffery Haley
    2 years ago

    Im looking to replace capacitor in my window ac. its a 45+15uf 370VAC. im having trouble finding a replacement part. any help would be nice. thank you

  • david vybo
    last year

    Call him back, make him take it out. Replace it with OEM specs. No matter what he or she says. Do not read all of the posts. Just do it. I have been burned in the past and the BEST advice I have ever had was to buy OEM for my system. I have stories but will not take the time here. Just get the same capacitor you had. What most of these newer guys are trained to do is to fix and sell WHAT IS ON THEIR TRUCK! It is the same as new estimates or quotes, they sell you and push what is in stock.

  • HU-69996403027
    7 months ago

    needs to replace with correct capacitor +/- 10%

    440vac can replace 370vac but not other way around

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