Using a too-big capacitor temporarily (40/5 instead of 30/5)

My other AC (number 2) (for those who remember my other number 1 unit's problems) acted up and the capacitor is bad (confirmed after checking with a multimeter.)

Two related questions: The last AC tech who came (not me) replaced the dual cap with a 35/5, although the compressor says use 30 (the 5 for the fan is fine/matches.) It was 2 years ago, I would have thought the capacitor would have lasted longer, but it's definitely bad. There's a little swelling on the bottom, although it's still otherwise new and shiny looking.

What are the repercussions of a too-large capacitor? Would that have had anything to do with the dead ones early demise?

Question 2: I can get the right capacitor tomorrow (Grainger) for $18 or today for $40 at another place. However... I have a 40/5 capacitor sitting around from years ago that's still good.

The cheapskate in me is tempted to use the 40/5 just for today and get the $18 capacitor tomorrow. This is a continuation of the earlier question, the repercussions of a too big capacitor (although in this case, question 2, it would just be for a day)

Thanks in advance!

 

The motor manufacturer select the capacitor's capacitance for maximum starting torque based on the motor construction and closest capacitance available. You have to accept the risk of ruining the compressor motor when using a different capacitance value. The new capacitor's voltage rating must meet or exceed the original capacitor's voltage rating. Personally, I would suffer the one day to get the correct capacitance capacitor.

 

Some compressors can handle the extra starting/run boost however the results are unpredictable.
We could never recommend using a larger one.

 

I weighed all the pros and cons, carefully considered that there was a ticking clock since I may end up running into the weekend, stores closed, that sort of thing, then balanced my time vs. money for drive time, as well as time vs. money vs. the risk of a delay (what if the order was delayed?) Upon weighing all the the data, I decided to go to the local store, spend $40 instead of $18, and I'm back in action.

(Translation: My wife made me get the $40 one, TODAY!)

Thanks for the advice all.

 

Absolutely.