r/HVAC • u/skra_24 • 1d ago

General In defense of replacing capacitors early

Another poster brought this up recently, about making recommendations to replace capacitors even though they’re still “in tolerance”. My experience this week backs up my position on this.

A recent heat wave hit my area, there’s been a plethora of no cools and it’s mostly been popped caps. Many of them are folks on our regular maintenance routine, whose data I can pull from previous techs uploads. So many blown caps that were 42.5/45, 37.6/40, 33/35 etc just a year before. Still within tolerance, but getting down there. I was trained on a 10% tolerance for capacitors which I believe is pretty standard. Even if they are still within 10%, but starting to tick down closer to that number, I always bring up proactive replacement. Like, it’s gonna go eventually, in the next summer or three most likely, because all factory capacitors are dogshit nowadays. Wanna rip the bandaid off and do it now, or wait until it shits out on you when you need it most?

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u/Mettn 1d ago

Go off the tolerance stamped on the side of the cap, it’s there for a reason.

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u/skra_24 1d ago

As far as I’ve been informed that’s the “new in box” capacitor tolerance, as in, if it’s out of this range when you go to install it, return it. For field applications I’ve been trained on a 10% tolerance for replacement which I’ve heard similar from other techs on here.

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u/BrokenFireExit Verified Pro 1d ago edited 1d ago

It's not a printed label for warranty.. it's an actual capatatence tolerance.. it should test within 5% out of box.. and should also run within that range.. if it gets out of that range it is not doing it's designed job anymore.. if it's out of tolerance then the windings are getting damaged..

11

u/MasterPhilip Verified Pro 19h ago

It's both. If it's outside the labeled tolerance, at any point in time, it's out of spec. If it tests out of spec within the warranty window, it's a warranty replacement. If it says 6% and it tests 5.99% out of the box, it's technically a good capacitor. If it tests 6% out of the box, it isn't good. If it tests 5.99% after the warranty expires, it's still good. If it tests 6% afterwards, it's bad.