Larger Capacitor Installed Question


Old 07-11-18, 12:33 PM
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Larger Capacitor Installed Question

Hello - I'm at the end of my rope trying to have someone resolve my AC issue

I have had 3 seperate people come out to my location to look at my system.

The second person replaced a 35-5 capacitor on my compressor with a 40-5 capacitor. Verified with trane that it should have a 35-5 in there.
The third person said this most likely fried my compressor and that I need to have them remedy the situation.

Is this correct that a larger capacitor could fry my compressor? The fan runs fine - which I take is because the 5 in the capacitor rating matches what is supposed to be in there.
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Old 07-11-18, 02:21 PM
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Here is a link to a website with information on how detrimental a wrong value capacitor is.
Old 07-11-18, 03:34 PM
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Welcome to the forums.

So is the compressor fried ?
If yes..... the compressor may have already been going bad.
Old 07-12-18, 04:13 AM
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It is highly unlikely that the higher value capacitor did any damage to your compressor.
The article about capacitor replacement is very interesting but even though it is aimed at electrical students is not 100% accurate for refrigeration compressors.
There is often a range of capacitor options available for a compressor, the specific one would be determined by both the compressor maker and the manufacturer of the equipment.

Capacitors will often fail when a compressor begins to have age related
problems, either mechanical or electrical.
Did the last tech say exactly what is wrong with the compressor???
I am not sure if "fried" means the compressor windings have shorted to ground, the compressor windings have the wrong resistance between themselves or the compressor is mechanically seized and will not start........You should have been given a detailed explanation.

If the compressor does not show any continuity between the compressor windings and ground and a few ohms resistance between the windings itself it is not "fried".
If it is not "fried" then it is possible that the 40 mfd capacitor is bad then it would be worthwhile to try a different capacitor.
A capacitor alone is common for ac units but does not give the motor a lot of boost to be able to start.
A common accessory for techs who really try to repair things is an auxiliary boost capacitor with a built in starting relay.
If windings are not fried may be worthwhile to try a new run capacitor and a boost starting capacitor.

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