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Induction electric motor starting design (C) InspectApedia.comAir Conditioner & Heat Pump Capacitor FAQs

Air Conditioning & Heat Pump FAQs about troubleshooting, choosing, and wiring a capacitor for motors used in this equipment: the compressor motor, condenser unit fan motor, or the indoor air handler blower fan motor.

These questions & answers about fixing problems with air conditioners & heat pumps were posted by readers at an A/C or heat pump diagnostic page.

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Air Conditioning & Heat Pump Start / Run Motor Capacitor Troubleshooting FAQs

Dayton dual motor run capacitor, round (C) InspectApediaThese questions & answers about diagnosing trouble with air conditioners and head pumps were originally posted at AIR CONDITIONING & HEAT PUMP SYSTEMS

A good place to look for diagnostic procedures is DIAGNOSTIC GUIDE A/C or HEAT PUMP.

Article Contents

Also see CHOOSE a START or RUN CAPACITOR FAQs

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HVAC Capacitor FAQs

Helpful diagnostics are

at TEST a MOTOR START or RUN CAPACITOR

and at CAUSES of HARD STARTING ELECTRIC MOTORS

How do I find out what kind of capacitor is used on my A/C unit fan?

Need to know what type of compressor, fan capacitor is used. Unit installed 02/1989 - On 2020-06-22 by Wayne

Reply by (mod) -

Wayne

Please see the guidelines at

CAPACITOR SIZE DETERMINATION for ELECTRIC MOTORS

And you will see some tables giving typical capacitor values that we might use as a starting point if we have no data about a motor

 

Replacing our air conditioning compressor capacitor didn't fix the trouble

I replaced the 50/3 MFD capacitor with a new one. Noticed the outside compressor fan running at half-speed as before when the indoor TT is set to OFF (yes, it's baffling).

As soon as the indoor TT was switched to ON, the fan spun to full speed, then the 30Amp breaker tripped immediately (maybe due to compressor malfunction).

Was hoping the new capacitor would resolve the issue, but looks like seized compressor and/or a bad controls in the outdoor compressor/condenser unit as you mentioned. Thanks again for your help. - On 2011-07-09 by TN-Goose -

Moderator reply:

Before launching into a compressor replacement, I'd want help from an on-site HVAC repair technician who can check the current compressor's operation, current draw, and staring trouble.

Particularly I'd also want to check the control relay and board, and I'd check the compressor's current draw for signs of a failing electric motor.

Also see CAPACITOR SIZE DETERMINATION for ELECTRIC MOTORS

 

A Fried Lizard shorted out the capacitor in our compressor / condenser unit, now we have no A/C

I found a fried lizard laying across what appears to be the terminals to a large capacitor. The AC will not kick on. Could this have shorted it? It is a RUUD unit. On 2012-07-22 by Viv

Reply by (mod) -

Viv,

Yes indeed an animal shorting out electrical wiring terminals at a start/run capacitor can destroy the capacitor or other components.

Call your HVAC service company for repair help. It might be that all that's needed is a new capacitor.

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Thank you to our readers for their generous comments

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...THIS IS SO COOL!! Have to tell my friends about you! - On 2011-06-08 by Livvy

Cool website thanks - On 2011-05-28 by jay

Thanks for so much info. been a big help. more power! - On 2011-06-17 by robert

Reply by (mod) -

Thanks for the Kudos and encouragement. We've worked hard on this material for over twenty years so we're very grateful when readers find it useful and trusted.

We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles.

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Continue reading  at DIAGNOSTIC GUIDE A/C or HEAT PUMP or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see this AIR CONDITIONING & HEAT PUMP SYSTEM FAQs INDEX Q&A on air conditioners or heat pumps that won't turn on or won't run properly.

Or see these

Recommended articles

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A/C or HEAT PUMP MOTOR CAPACITOR DIAGNOSTIC FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS

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