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Will Wrong run capacitor cause damage to AC?

Posted by ncwolfpack (My Page) on
Tue, Jun 26, 12 at 21:59

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.


Follow-Up Postings:

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RE: Will Wrong run capacitor cause damage to AC?

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


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RE: Will Wrong run capacitor cause damage to AC?

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.


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RE: Will Wrong run capacitor cause damage to AC?

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 <<== Is it really 80 MFD required??
Start Cap. MFD/Volts 189-227


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RE: Will Wrong run capacitor cause damage to AC?

yes you need the right size cap within 5 %.


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RE: Will Wrong run capacitor cause damage to AC?

Under-voltage caps will fail faster, anything from instant to years later.

Under sized (smaller than needed microfarad) will result in longer starting times, and if excessively undersized no starting.

Larger than needed microfarad values will not cause much of any problems (especially for a start capacitor).

A 'hard start kit' is a larger start capacitor with a method of removing it form the circuit after start.

A larger than needed run capacitor will not have any real affect.
Depending on the cap and motor it could improve efficiency or decease efficiency very slightly.

You need to stick with the voltage.

Going up slightly capacitance will not be a problem, but down can affect operation.


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