Sooo our a/c just quit...

[HaroldMHedge]

After shutting off the power to my Trane heat pump to replace the capacitor, I learned the hard way that my system has a 30 minute delay following reenergizing the system.

[pwd72s]

https://www.youtube.com/watch?v=bWH38Rg1iMI&ab_channel=HVACSchool

[A930Rocket]

Originally Posted by mattdavis11

…Easy job, just don't forget kill the power to the unit (condenser) and then discharge the capacitor first.

Amazon sells capacitors, but I couldn't wait until Monday.

How do you discharge the capacitor?

[red-beard]

Originally Posted by A930Rocket

How do you discharge the capacitor?

I have a 100 Watt 25 Ohm resistor. Some people use a screw driver. They bleed down eventually. I check with a Volt meter and discharge if necessary.

[Scott Douglas]

Just to close this thread out, it was the start capacitor.
I mentioned I'd posted here and everyone thought I should replace it myself. The guys confirmed that getting someone to sell one to me was a problem.
This is only the second time in 10 years we've had to spend money on the system so I'm not too worried about the bill.

[javadog]

When you have to replace a capacitor, try to find one made in the USA, (this will be difficult). Failing that, find one that’s made in Mexico. Do not install one that’s made in China.

[Baz]

[Neilk]

I have a couple of spare capacitors that I bought for $30 after going without AC for a day and spending $150+ to get it repaired.

[aschen]

I definitely keep spare caps on hand. Really nice to be able to replace these things with out waiting for the amazon guy or running around to AC supply stores (which always seem to close at like 4).

For the fan start cap you can give the blade a with a screw driver or something and it will spin up. Works in a pinch if you need to cool the house.

Single phase AC induction motors seem so archaic and crude in the year 2022, but they work and are simple I suppose.

[Baz]

Originally Posted by Scott Douglas

Just to close this thread out, it was the start capacitor.
I mentioned I'd posted here and everyone thought I should replace it myself. The guys confirmed that getting someone to sell one to me was a problem.
This is only the second time in 10 years we've had to spend money on the system so I'm not too worried about the bill.

Scott,

Glad it worked out for you - easy fix - so not too expensive.

You can get these from Amazon. Grainger as well. Other places. I bought from eBay in the past also.

If it's something you don't want to mess with - I respect your decision.

Happy Friday!

[mattdavis11]

Originally Posted by aschen

For the fan start cap you can give the blade a with a screw driver or something and it will spin up. Works in a pinch if you need to cool the house.

That's a good point. I tried that and the fan worked, but the compressor did not. My capacitor is a dual purpose. I wonder if its possible to only blow half of the capacitor on a dual.

[GH85Carrera]

I had replaced our capacitor after the cooling fan was running, but the compressor would not kick on. A few days later we had a very momentary power blip. I went to check on the ac unit, and same thing, the compressor was not running. I rigged up a small hose and had it wet down the compressor to cool it down. 20 minutes later, I removed the hose, and fired it up. When the thermostat finally decided it had been long enough the compressor came to life, and all was well. That was 45 days ago, and we have had a lot of HOT days.

I still need to restock with a fresh spare capacitor.

My Fluke 75 meter does not have the setting for checking the capacitor mention in that excellent video above. I have had my Fluke for 35 or 40 years.

[javadog]

One way to test a capacitor without using a meter is to touch the two magic terminals with your two index fingers and measure how high off the ground you are launched. All you need is a wooden ruler and a witness.

Legal disclaimer: Do not actually attempt this, it will kill you and all of your unborn children.

[javadog]

Originally Posted by mattdavis11

That's a good point. I tried that and the fan worked, but the compressor did not. My capacitor is a dual purpose. I wonder if its possible to only blow half of the capacitor on a dual.

‘Reckon so…

[aschen]

I have one of these reasonably priced grey market flukes with cap checker.

They are real fluke but intendend for low cost markets. Same fluke quality and a bargain imho though. No fluke warantee or us support however


https://www.ebay.com/itm/373557024598?epid=26041733181&hash=item56f9bbd756:g:h5oAAOSwg2lgh7YE

[mattdavis11]

Originally Posted by javadog

One way to test a capacitor without using a meter is to touch the two magic terminals with your two index fingers and measure how high off the ground you are launched. All you need is a wooden ruler and a witness.

Yep, that's why they're measured in microfareds. It's a low fare short ride.

[javadog]

Guaranteed to be painful and probably surprisingly loud, as well.

I doubt there are very many repeat customers.

[Scott Douglas]

I looked at the box and recognized the name from one of the videos here but I forget which one. I watched the guy change it out and he didn't really check to see if it was discharged but he was very careful to only touch one wire at a time.
I should have photographed the whole deal. I know where it's located now and what kind of contortions I'll have to go thru if I ever have to change it again. We don't use it all that much compared to what most of you do, but it has been used more in recent months as it seems the weather has been a lot hotter than it usually is.

[Scott Douglas]

Originally Posted by Baz

Scott,

Glad it worked out for you - easy fix - so not too expensive.

You can get these from Amazon. Grainger as well. Other places. I bought from eBay in the past also.

If it's something you don't want to mess with - I respect your decision.

Happy Friday!

The best part is Baz, that my wife won't blame me for it not working since I didn't fix it.

My fear of electricity comes mainly from an experience my cousin went thru that ended up killing him. He was about 10 yrs old and fishing on a private lake in an aluminum boat. They went under a bridge of some sort and he reached up and touched it. Something hadn't been wired correctly and he was electrocuted. I never really helped my dad out much when he was working on electrical stuff at our house as a kid. He had studied and taken the exam to qualify himself so he could work on the house without needing a paid professional. I wish now that I had paid more attention to how things were done but that's water under the bridge now.

[fintstone]

Just be glad you did not need refrigerant now. You would have to contribute an arm or leg...and then in a few weeks, it would all leak out and you would be back to square one.