HVAC Capacitor

[LoudMusic]

The HVAC was complaining about HI PS, so we shut it down and cleaned all the filters, pipes, pumps, and fittings. Reassembled, switched it on, blowing cold, feeling good.

Then we smell burning! Shut it down, pull it apart, discover a burnt wire on the capacitor. Is this as simple as replace the capacitor and crispy wires, or is it indicative of bigger issues?

See attached image for charred wire. We have switched off the breaker.

[Jammer]

Hello, Loud Music.


I do my own A/C repairs and replaced the capacitors on the A/C in my house (on land) a couple of months ago.


The burned wire is due to a failing connector where the wire attaches to the capacitor. My advice would be to replace the wire and connectors. While there is no harm in replacing the capacitor, it would be strictly a preventative measure at this point since there is nothing to indicate that there is something wrong with it.


It is common for wires to overheat at their terminals due to corrosion or improper crimping technique. If there were a more serious problem resulting in overcurrent in the wire, the insulation would be evenly burned along the entire length of the wire.


Fair winds

[LoudMusic]

Ah, excellent. Thank you for the information. Sounds like I need to get some spools of cable and start replacing some of these.

[a64pilot]

It’s almost certainly from a loose connection, but I would replace the cap too, they are cheap and easy.
I would only clean and make sure the other connections were tight and I like to apply some silicone grease to prevent corrosion, I would only replace the burnt wire.
You literally squeeze the female spade connector just a tad to tighten it, and resist excess wiggling when you push it back on, that can loosen one.

That cap appears to be a dual cap, three terminals, take it to a HVAC supply place 99% sure they will have the right uf rated one, for $20 or so.
That burnt wire seems to be from the fan circuit I believe.

[OzePete]

This is typical damage caused by spade connectors. Spade connectors lose conductivity and heat results.
We hate them and don't use them.
Best to solder such electrical connections where possible.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[Dave852]

Once you remove the cap you will see the size printed on the side. Since it's a dual cap it's will be two numbers such as 45/5 for example. The terminals will be labeled "herm", "fan" and "c". Label each wire before disconnecting

[deluxe68]

And check the wires for brittleness. Overheating might require replacement of the whole wire if there is not enough to reterminate.

[LoudMusic]

Two successful projects today. One was to replace the shower pump, which had a cracked planetary gear that followed through with destroying the thing. And replacing a burnt wire in the aircon control.

Today's rewards for hard work are a shower and a cool cabin for sleeping. Heyooooooo!!!

[senormechanico]

Originally Posted by OzePete

This is typical damage caused by spade connectors. Spade connectors lose conductivity and heat results.
We hate them and don't use them.
Best to solder such electrical connections where possible.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

I'm coming late to this thread and was ready to post exactly what what OzePete wrote.


Quarter inch spade terminals no longer exist on ALL of my boat's wiring. They have been banished !!!