change capacitor on outside AC unit

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anyone ever change the capacitor on their outside AC unit?

2nd week w/ an A/C tech no-show. I've google-diagnosed the problem. certainly couldn't hurt it by replacing this part, even if that doesn't resolve the issue. seems super simple
 

Cycleops

Legendary Member
Location
Accra, Ghana
I gotta tell you RR that it never gets that hot in the U.K. Never had the need to change the capacitor on ours here, only re-gas it.
 

irw

Quadricyclist
Location
Liverpool, UK
anyone ever change the capacitor on their outside AC unit?

2nd week w/ an A/C tech no-show. I've google-diagnosed the problem. certainly couldn't hurt it by replacing this part, even if that doesn't resolve the issue. seems super simple

Hmm. Capacitors you say…Apologies if you are aware of the dangers already, but if you don’t, please be aware that capacitors can be very dangerous, even if the equipment hasn’t been turned on in a while.

 

Tenkaykev

Guru
Location
Poole
Is the capacitor for the compressor? The “ start” capacitor is electrolytic and usually of a high value in the region of 80-250 mfd. “ permanent “ or run capacitors are usually of lower value. Some will have a discharge resistor wired across the terminals, but its good practice to short the terminals with an insulated screwdriver. I changed many hundreds over the years when I repaired Electric motors.
 

ColinJ

Puzzle game procrastinator!
The value and voltage is often printed on the capacitor.

Which can be found decorating the ceiling if you do what the guy in the video did! :laugh:
 

Andy_R

Hard of hearing..I said Herd of Herring..oh FFS..
Location
County Durham
Which can be found decorating the ceiling if you do what the guy in the video did! :laugh:

The guy in the video is actually a very experienced and qualified electrical engineer. He has a lot of videos on You tube where things always go spectacularly wrong, but he never gets injured - strange that isn't it...Look up "ElectroBoom"
 

presta

Guru
capacitors can be very dangerous, even if the equipment hasn’t been turned on in a while.
Most who work with electronics have had small electrolytics go pop every once in a while, but the ones that are big enough to be dangerous have safety vents, so they don't do anything worse than squirt a load of mess out of the relief valve rather than exploding. I've seen that guy in that video before, he comes across as someone who's putting on an inept act for 'comic' effect.

If it's a high voltage circuit, the bigger risk with capacitors is a charge remaining after switch off, not only should you ensure they're discharged before handling, but some are unaware that they need to remain shorted. If you discharge a capacitor then remove the short, they can partially recharge themselves because the electrical stress remains within the dielectric for some time. The main isolator switches on our big transmitters had contacts that shorted the main HT supply, and kept it shorted all the time the power was off.
 

the_mikey

Legendary Member
anyone ever change the capacitor on their outside AC unit?

2nd week w/ an A/C tech no-show. I've google-diagnosed the problem. certainly couldn't hurt it by replacing this part, even if that doesn't resolve the issue. seems super simple

When you say "the capacitor" it makes me think it's simply a capacitor for getting a brushless motor running and not a power supply or control board issue, do it if you think there's power getting to the motor but it's failing to turn somehow.
 

Tenkaykev

Guru
Location
Poole
Most who work with electronics have had small electrolytics go pop every once in a while, but the ones that are big enough to be dangerous have safety vents, so they don't do anything worse than squirt a load of mess out of the relief valve rather than exploding. I've seen that guy in that video before, he comes across as someone who's putting on an inept act for 'comic' effect.

If it's a high voltage circuit, the bigger risk with capacitors is a charge remaining after switch off, not only should you ensure they're discharged before handling, but some are unaware that they need to remain shorted. If you discharge a capacitor then remove the short, they can partially recharge themselves because the electrical stress remains within the dielectric for some time. The main isolator switches on our big transmitters had contacts that shorted the main HT supply, and kept it shorted all the time the power was off.
Yes, that caught me out once, a cap I’d discharged earlier gave me a belt when I was refitting it later. It became second nature to touch the terminals to my bench vice after that incident.
 
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