Any A/C Technicians in the house?

[mikeatrpi]

The central air for my house stopped working a few days ago. Its an older Williamson unit - house was built in 84, and I don't know if its been replaced since. Symptom - on the outside unit, the fan runs but the compressor does not. I heard it buzz, but it doesn't run. Once the fan is going you can't hear the buzz anymore.

I found the schematic, and it looks like the red wire between the compressor run capacitor and the contactor burned out. The spade connector is a loose fit, but I don't know if it was loose before the wire burned up, or not. I also found evidence of critters living in there.

At the store this morning I bought a new cap. 40uF, 370V, $16 - made in China but I'll roll the dice and I didn't have a choice.

1) Is there anything special about the wire used here? Is normal 14G stranded an OK replacement?

2) The cap isn't bulged, but the terminals are corroded and loose where the fire happened. Is it correct to replace the cap?

3) A contractor was at the store with me. He looked at the wire and told me to suspect my microwave, oven and refrigerator... and he told me to call my insurance company. When he left the clerks told me to ignore him, that he's been having a bad day. But still, am I going to burn the place down if I goof this up?

I have a referral to a reputable tech if required.

Advice anyone? Many thanks!

 

[comedyman809]

sounds like you compressor is throwing in the towel.

1984 installed......it may be time.

if your compressor is still good, that start cap may be the problem and if not, then your refrigerant leaked out.


this is one of those times where you will need an a/c tech.

 

[comedyman809]

got 10k-15k?? hopefully its an easy fix

 

[Cuda]

I'd say your doing all the right things. If it does work for you after replacing the cap. I'd throw an amp meter on your compressor line to see what it's drawing. If it's higher than the name plate you could be needing a new unit.

 

[ebasista]

You're on the right path here. Caps go bad all the time. With a unit as old as yours I would have bought a kick start/hard start capacitor to give the compressor a bit more juice to get her moving.

Remember this though, this compressor is ancient, and if you do get her running (very likely) you should be planning on an HVAC upgrade in the near future.


Replace the wires with the same gauge and stranded. I've seen burned out contactors where critters decide to call them home and likewise corrosion/loose wires causing them to melt.

I hope you disconnected the power and left it off as soon as you had the problem.....reason being that the buzzing sound is the compressor getting power and trying to start......if it keeps doing that for too long the compressor will eventually burn out.

At this point you have nothing to lose, so good luck

 

[mikeatrpi]

Update -

I installed the new cap and replaced that one section of wire. I also used some dielectric grease on the connectors and pinched the old ones to create a tighter connection. I'm happy to report - its working again!!!!

We probed the old cap, and it was a short between the terminals. That's probably what caused this wire to flame out.

Thank you all!

 

[comedyman809]

yeah, i used to make service calls to hosipal/labs low temp freezers.

75% of the problems were dead start caps.

 

[Slip_Kid]

Those starter capacitors go bad all the time, you saved yourself a service call.