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AC Capacitors Test (air conditioning)


billybob

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Hello, 

Fan or condenser motor not working. After power surge

from lightening strike am testing

with  simple analog meter, the dual run capacitor. Continuity check shows good. Meter has.no capacitance check function. So,

what are the chances that cap is really good?

Turns the compressor on but motor for fan remains cool to the touch like no power is received.

Guess that the cap could be good only for the compressor side.

Motor for fan is old looking and maybe an original 20 y/o.

Thanks

 

 

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you can check the cover of the AC  to see where the lightning strike hit ,  it will be a burn mark  -wherever it hit would show the damaged area -------usually the capacitor and the contactor are the parts to replace

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1 hour ago, boom3 said:

AC contractors generally charge about 5X list (Mouser, Allied, etc) for motor run caps (not including labor). Just sayin'...

plus the service call charge and the labor and the shipping on parts

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22 minutes ago, Jeff Matthews said:

If we're talking about the same thing, an easy test is to turn on the a/c, and while you are at the condenser unit, use a stick to poke inside the top and give the fan blade a good nudge clockwise.  If it starts spinning, it's a bad capacitor.

you're super handy with an AC but you can't fix a  dryer ------love it -

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Lol, appreciate the ideas.

Drove a 100 mile rounder

for the correct cap replace.

No cigar so am eliminating

Caps for the moment. Have

a hard start cap that tests

good.and another ordered.

Looking like the fan now or/and

the control board. The breaker

never tripped and the low voltage

fuse inside never blew. There is a 3 amp fuse in the control board

that is inline with the thermostat

that blows but, thinking it is protection against my tinkering.

Checked continuity from the new stat I just installed to the control

board.

Brown fan wire good.

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6 hours ago, billybob said:

Motor for fan is old looking and maybe an original 20 y/o.

Thanks

 

 

 

Replace the fan on each of your units.  Residential units do not have a fan sensor and when the fan dies your compressor will die right away.  If your units go, you need to replace everything (including the evaporator) to covert to the new Freon which might even require larger line sets depending on how far away the units are.  This will be very expensive. 

 

This info is from a few years ago.  I replaced all of my units when the R22 units were being phased out even though they were working on the advice form a friend in the business. 

 

You should also look at a 5-2-1 hard start kit. 

 

 

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20 hours ago, boom3 said:

AC contractors generally charge about 5X list (Mouser, Allied, etc) for motor run caps (not including labor). Just sayin'...

 

More like 10x

 

About 20 years ago I started buying my own AC capacitors on ebay. Price is usually between $20 and $30 bucks nowadays. I learned the hard way after being shafted $300 for a 15 min.  visit and a $15 part swap. When I discovered the cost of the real cost of the capacity I was livid. This was back in the late 1990's. God forbid what they charge nowadays for such a simple job.

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16 hours ago, billybob said:

Lol, appreciate the ideas.

Drove a 100 mile rounder

for the correct cap replace.

No cigar so am eliminating

Caps for the moment. Have

a hard start cap that tests

good.and another ordered.

Looking like the fan now or/and

the control board. The breaker

never tripped and the low voltage

fuse inside never blew. There is a 3 amp fuse in the control board

that is inline with the thermostat

that blows but, thinking it is protection against my tinkering.

Checked continuity from the new stat I just installed to the control

board.

Brown fan wire good.

-lucky no one was outside when the lighting hit , I lost a friend that way

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Last summer the cap failed on my A/C compressor.  It was the origial GE cap from when the unit was installed in 1986.  When I was buying a new Dayton cap at Grainger, I mentioned to an employee how long the original cap lasted.  She said, "I can guarantee this new capacitor won't last that long".  I bought two more to have on the shelf.

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