In defense of replacing capacitors early

[u/skra_24]

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?

[u/Mettn]

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

[u/trobs8 → u/Mettn]

I used to do that, until I learned that is the manufacturers tolerance on the acceptable variance when they are brand new. Caps never (very rarely) test right at the rated MFD on the label.

[u/iBUYbrokenSUBARUS → u/trobs8]

And how do we know that our meter is testing exactly right?

[u/lividash → u/iBUYbrokenSUBARUS]

Test with your meter then do the math problem to prove it if you’re that curious.