Diagnosing home AC unit

[Skippy722]

Compressor that is very hot is off on a internal overload. Pull disconnect top grill put a water hose on top of the compressor running a stream water over the compressor for 30 minutes. After turn water off wait 5 minutes is compressor gets warm run water for another 15 minutes.This should cool it off and reset the overload. Just because the compressor will feel cool before 30 minutes it the internal temp that you can't feel. If compressor starts are the condenser coils clean? Might want to pull the top of unit see if the coil is made up of two coils if so coils separate at opposite piping end and can be spread apart to clean about 80%. Condenser fan could also be failing when this happens compressor still will run but sound differentially, it stops pumping and bypasses gas and run till it overheats.

Do this, but be very careful if you have a micro channel unit. Gentle water pressure only if it is. 2.5uF on a 5uF cap is bad.

 

[Lubener]

Breaker doesn't do much when the energy is stored as charges inside the capacitor (it is like a big battery), if you have a large enough resistor (say k Ohms range), use that to short it instead of the screw driver, hold it with a plier with rubber coating on the handle and wear gloves for extra insulation.

Never said shutting off the breaker would discharge the energy stored in the capacitor. It's not good practice to open up and mess around inside the condensing unit without shutting off the power first. Sounds like you advising that shutting off power doesn't do much.. Your advice would benefit an undertaker.

 

[SatinSilver]

This AC unit is only about 2 years old, strange that this part died so soon.

What brand AC is it?

 

[mcdonnell]

my unit not the op is a 23 year old bryant. all original. never serviced. the capacitor was made by GE. The new one Chinese Junk.

 

[zzyzzx]

Good pictures of the supposed bad capacitor would be nice. We need to look for bulges, etc if there is nothing obvious wrong with it.

 

[mcdonnell]

Good pictures of the supposed bad capacitor would be nice. We need to look for bulges, etc if there is nothing obvious wrong with it.

 

[SouthernHooDad]

replacement capacitor will be about $20. I replaced one 2 weeks ago.

Per your photo... P/N 97f9849 is a 40/5 dual run capacitor - 370v. Do you have a Grainger location nearby. They'll have it in stock. Otherwise find a local HVAC supply house. Quick easy replacement. If that doesn't fix it call in the professional.

 

[mcdonnell]

Guys I already replaced the supposed bad bulgeless capacitator . Unit fired right up after replacement the new one was 12 dollars. Thanks

 

[Kawiguy454]

Breaker doesn't do much when the energy is stored as charges inside the capacitor (it is like a big battery), if you have a large enough resistor (say k Ohms range), use that to short it instead of the screw driver, hold it with a plier with rubber coating on the handle and wear gloves for extra insulation.

He was trying to say shut off the power before shunting (discharging) the capacitor. ...shorting it powered up may cause some fireworks.

 

[mcdonnell]

I stand corrected apparently my replacement capacitor was made in God Bless America. That's two items this week I purchased made in USA capacitor and genrac power washer.

 

[zzyzzx]

Guys I already replaced the supposed bad bulgeless capacitator . Unit fired right up after replacement the new one was 12 dollars. Thanks

That's what these things should cost, and why I don't shop at Grainger. Two summers ago I needed a contactor. It was $9 on Amazon, or several times that locally ($35 or more). I used a window A/C unit while I waited in a mail ordered the part.

 

[mcdonnell]

Yep same part online is 8 dollars

 

[92saturnsl2]

What brand AC is it?

It's a Comfortmaker brand, the unit is made by International Comfort Products, I think a division of Carrier.

 

[92saturnsl2]

Replaced the capacitor today and it fixed the problem.

The old capacitor looked fine physically- there was no bulging or anything of the sort, nothing about the appearance would have led me to believe it's bad. But I got no capacitance reading on the HERM side, and the fan side was reading 2.5uf instead of 5.

My cheap E-bay meter must be halfway accurate because the new one tested right at 45/5 uF within a tenth or two.

Capacitor cost $24 at Winair, I guess if something on the AC were to fail, that's the one you want it to be! Thanks to all for the help/suggestions.