WHY CAPACITORS FAIL in Air Conditioners! Watch it Break!

In this HVAC Training Video, I show a Run Capacitor Failing in an Air Conditioning Unit in Real Time!! I show 2 ways to measure the MFD of the capacitor with a multimeter to see if it's good or bad. I give 4 reason why a run capacitor would go bad. Supervision is needed by a licensed HVACR Tech while performing tasks as Experience and Apprenticeship garners Wisdom and Safety.

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⚠️ Disclaimer:
Information in this video is intended for educational purposes only. Any work related to the topics in this video should be performed by licensed technicians or by apprentices under the supervision of licensed technicians. AC Service Tech LLC is not responsible for any possible damages or injuries caused by the use or misuse of any information provided.
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#hvacr #hvacr #hvactrainingvideos #hvactraining #hvactraining101 #acservice #acservicetech #capacitors #airconditioner #acunit #capacitance #break #MFD #hvacunit #training #realtime
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[vernroach]

I'm a former instructor, still running service...This is an excellent video...Better than most, clear, easy to understand, and well done....Thanks again for what you're doing.

[classicpontiac]

A little tip from a former residential tech, replace all 370 vac capacitors with 440 vac capacitors using the correct microfarad rating. IE: 35/5 mfd. 370vac dual capacitor fails, replace it with a 35/5 mfd 440vac capacitor. I can't ever remember having a callback on the same unit for a repeat failure in 9 years of service. Good luck guys!

[henrypfister]

Most educational A/C repairman I have ever seen. I'm an electrical engineer and I say he knows his stuff.

[BryanTorok]

I am amazed how much knowledge is available on the internet for free from folks willing to share it. Thanks for making these videos. Also, thanks for providing the Amazon links. Looking through them reminded me that I need to get some vacuum pump oil and pick up a swaging tool for an upcoming job.

[dandaman]

Craig, you have a natural talent for explanation and always demonstrate these concepts. I'm a visual learner and appreciate it. The Mini Split book is one of a kind!
We didn't get much time to chat, but I hope to see you next year at the HVAC Symposium in Clearmont!

[cdf]

Thanks. I had a string of cap failures on a new Trane sysyem. After the first 3 or 4, the AC guy measured voltage. I had a bad street transformer and 1 leg was 115, the other leg was 132. Town came and replaced it, no problems ever since.

[LRBennettInc]

Such a great lesson for every tech who now can't sell them a new fan motor because the homeowner just watched this. Very good video.

[mr.b]

I’m a Contractor now but been in the HVAC trade for 18 years and I still learn from your videos, good stuff and some of it I’ve forgotten about. Thanks for putting in the effort!

[douglaswatters]

When I was a kid the capacitors lasted the entire life of the unit. I've seen caps so old the only reason they had to be replaced was because the 25 year old terminals had rusted through and you couldn't get a connection on them anymore. Those caps were oil filled and weighed a couple pounds. They were also a lot bigger in physical dimensions, a 30mfd was about 7 inches long oval can.. The caps we have now sometimes fail in a year and feel like they're filled with air.

[spelunkerd]

For anybody wondering where the numbers come from, recall that impedance of a cap is 1/(2*pi*f*C). Plug that impedance into Ohm's law and rearrange to get C by itself, and assume 60 Hz. Dynamic testing like this will be much more accurate in a real world situation. Brilliant video!

[chriswtx]

I always keep a spare capacitor at home. After the first $250 bill for replacement, I learned to do it myself.. Only a $20 part so cheap to keep a spare. In Texas they are the most common failed part on a home AC and they charge an arm and a leg to come and replace it. Literally takes 5 mins to replace..Easy to test with a volt meter..

[badlucklazyguy]

Hands down this is the best video I have found on youtube for this topic. The guy didn't go to deep but just deep enough to give enough of the math behind what was going on to arm a DIY'er with with what they need to understand when replacing these caps themselves (or at least dealing with an AC contractor.)

[AXNJXN]

I honestly can't even remotely consider why anyone would thumbs down this video... It is distinctly, one of the absolute best explanations on YT for value, reason and explaining the math behind it. Job well done Sir.

[randyduncan]

Thank you for the great content! Having a clamp ammeter plus a good DVM makes checking the capacitance very easy as opposed to cutting the power, discharging the caps, disconnecting the caps and using a meter that can measure capacitance. I also like the fact that your way tests the cap under load. With the supply chain woes I think I'll buy an extra just in case. Everything in your A/C system is designed to fail after closing time on Friday in August.

[johnnytdufc]

I see several comments that share my thoughts here: A. Excellent delivery of information. No unnecessary pauses nor tangents, you stay on point and you are very concise. You ought to teach HVAC/Electrical if you don't already. I am very impressed. Oh, and you answered my questions. I had no idea what dielectric fluid was before today and that explains the size and shape of transformers on telephone/electric poles. Pure physics inside a capacitor...surface area for storing electrons. Color me schooled. Though I'm now more curious than ever.

[robs]

Thanks for the video! My HVAC capacitor recently failed and due to the recent heat wave and we could not get a vendor out. Was able to get a capacitor and install it with the help of videos like yours (locked out the circuit, waited, then tested for residual voltage). the old capacitor had good shape but the top was wet from electrolyte leaking. Thanks!

[shopart]

Thank you, your video is by far the best at explaining why capacitors fail. When I built my house I purposely placed the AC unit on the north side of my house away from the sun. Not only does it help save capacitors it also lets the unit run more efficiently.

[ethansmallsandthescaldeddo]

here in the US southeast im seeing alot of capacitors fail within the warranty of the unit, ive noticed that these capacitors are made by the same company, we replace them with a cap made by a different company from a different place and they last significantly longer for some reason

[chrisscott]

HVAC school was insisting caps fail due to overvoltage (transient / surge). When I suggested it was heat, I was essentially told I was stupid. I've had really good luck replacing with two capacitors to spread the heat load. I also agree with the commenter who suggests caps with higher voltage ratings. Everything I've seen suggests heat is the real culprit.

[johnnysfunzone]

EXCELLENT video! As mentioned by @classic Pontiac37, sometimes using a higher voltage rated cap will make things last longer. In petrochem control systems, I've seen blown out power supply filter capacitors that the manufacturer pinched pennies on and were within a volt or 2 of the running voltage. Running "rated voltage" that close is not good in HVAC or in production plants running 24/7. We solved that problem by replacing all of those "too tight" VDC filter capacitors with ones almost triple the running voltage. No more failures.