A/c capacitor help

If your air handler overflow pan has a safety shutoff float switch you might want to check the pan for water. This will allow everything but the compressor to run, it’s happened to me before,

It’ll be fine. Honestly I don’t know if all single phase auxiliaries have a physical separation of exactly 90deg or if some are custom, but the bigger cap will just produce a shift closer to 90. Not a problem.
It *may not charge/discharge enough to get a full wave across the aux, but it will locate the prob and can be used until a better match is found even if that is some time out.

The other recent Capacitor thread, named AMRAD and Titan as 2 USA made caps.
I used the Amrad link in that thread to look up my 45/7.5 x370/440 cap, went to Ebay and ordered it at $33 to my door. Same sized Titan cap ran $15.

The Amrad site shows a more viscous/thicker insulating fluid than other caps.
Buy a couple as spares and you won't have to beg at local A/C supply when you are in a bind.

My 3 year old Trane unit had a China cap. Will install the Amrad and let it ride....

or anything else that was just "close enough
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My AC went out as a hurricane was kicking up. I had a close enough cap to fire the unit up until the storm had passed.

My AC guy said to definately go back with origianl spec one.

I’m not seeing it this way. I’m seeing a few percent more starting current and torque then possibly less or more running current across the auxiliary but not much of a change at all. Get some peace of mind from being closer to correct size but I don’t see this harming a healthy motor under any circumstances.

That probably didn't matter much in the R22 days when compressors, fan motors, and capacitors were better built. Today it's different when OEM's are cutting costs everywhere to meet efficiency standards. The tolerance to a few hundred more or less watts based on using a capacitor with slightly different specs matters. A healthy motor dealing with a few hundred watts more heat is how it becomes an unhealthy motor and a new motor costs a lot more than the right capacitor, even a premium US-made capacitor (the Titan HD's for my units cost me $20 each, new fan motor was $236 at the same supplier).

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What is it with all these capacitor threads?What causes them to fail?

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Heat & Voltage spikes (brown outs, etc) are the main reason they fail - can’t do anything about heat but surge protectors might help with the voltage surges - I have a surge protector on my HVAC condenser installed with a change out in Feb 2023. I’ve never had a capacitor fail either, but what I can guarantee if it does fail it will be on a weekend or holiday, hosting a party, hottest day of the year, returning from vacation to a hot house,….. at the most inconvenient time. lol. I keep a spare for that reason and know how to check for a bad capacitor with a multimeter & replace it. According of professional HVAC sites I peruse, capacitor failure the the #1 failure they deal with, followed by contactor failure, and then condensor fan motor failure.

I watched a Y/T channel where a HVAC company owner-tech in Lafayette started replacing the “cheap” capacitor in brand new units he installs with a better made USA made capacitor b/c he was getting so many call backs within the first year of installation with capacitor failure.

ETA: Why Capacitors Fail in ACs

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Have I just been lucky?

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Capacitors aren't made as well as they used to be. The metal and insulation films are thinner, they use organic/castor bean oil, etc. Buying Amrad, Titan HD, Mars capacitors that are USA-made is about the best you can do now but even they aren't built as well as the old ones.