Corroded/loose lead on compressor capacitor - Panasonic window AC

[fred_perkins]

We have a large Panasonic window unit (24000 btu, model #CWXC243HU) than is ten years old and has worked quite well over the years.  Evaporator and condenser fins are cleaned annually, and e+ filter get replaced every two weeks while the unit is operational.

 

Yesterday was a hot day (close to 90 F), yet the unit seemed to be running a bit colder than usual.  Turned up the thermostat but it still seemed to be running cold.  Then, around dinner time, as outside temps were cooling down, the unit stopped cooling and just churned out warm air.  The fan ran all night, but the compressor wouldn't kick on -- even with the thermostat turned down to 60.  Outside temps were in the 70s all night and already about 80 when we woke up -- rather uncomfortable for sleeping!

 

Pulled the unit out of the window this morning and found that the wired connector has corroded (or arc-ed?) such that the wire is no longer connected with the common lead on the condenser capacitor.  It's a dual cap with three leads, and the cap seems to be integrated within the compressor.  The connector seems to be brass and has a hole burned through the middle. The pin on the capacitor is partly intact, but some of it is gone.  I was able to clamp the wire (with clamping pliers) to the common pin on the capacitor and the unit runs and cools just fine.

 

Obviously, the clamping pliers are not a long-term solution.   But even if the brass connector on the wire were replaced, it wouldn't make very good contact since part of the capacitor's common pin has corroded (or arc-ed). 

 

Is it OK to just cut off the brass connector and solder the wire directly to the capacitor's common pin?  Or would the solder just burn up over time as the compressor runs hot?

[m_west5]

Are you able to read the micro-farad and voltage rating on the capacitor? I would not advise you to "repair" by soldering to the fried contact.

I googled your model number and not much came up in way of a parts diagram. You stated that it is integrated into the compressor. Could you take a close up pic and post? Did you try pulling on the capacitor to seperate it?

Be careful, capacitors hold a charge and will shock you, even with unit uplugged from outlet. You need to discharge from common to compressor and common to fan BEFORE handling.

What are the ratings and then search for a like cap that you may be able to use if the manufacturer part is no longer available.

[fred_perkins]

 

The red arrows point to the partially-burned-out connector and common terminal.  My theory is that the connector became loose and periodically arc-ed, causing a hole in the middle of the connector.  I temporarily clamped the remnants of the connector to the terminal, and the compressor kicks on just as it should and the unit runs perfectly.

 

Just to the right are the Run and Start terminals, which are just fine and show no signs of burn-out.

 

I have a multi-meter but it does not have a capacitance setting.

Edited July 12, 2014 by fred_perkins

[m_west5]

Thanks for posting the picture. It looks like you may be able to pry around the top of the cap to remove it. By the looks of it, it may be corroded in place and hard to remove. Did you try that? I have not worked on your specific model before, so I'm really not sure how to remove it.

You may be correct about the loose connection. However, other faults will cause this too. I would highly recommend taking amp draws and voltage readings on the compressor and fan. Also, visually test and/or inspect all other components and wiring. Compressors at initial start up pull a tremendous amount of current. A good quality true rms meter will show this. If you are not sure on how to check all of this, then call in a professional to get their opinion.

My major concern is obviously the fire hazard this presents. When that contact on the capacitor arced/burned, I'm sure some internal damage occured. It will most likely fail again soon.

I say replace the capacitor and thoroughly check out the unit to ensure it is functioning safely and properly. It's not worth risking life or property

[Budget Appliance Repair]

S T O P - Do NOT try to pry that out of the top of the compressor, that is NOT a capacitor.

 

Those are the Common, Start, Run connections to the compressor.  Clean all the corrosion off with a small file and emory cloth and replace the burnt connectors.   May have to carefully use a small grinding bit on a dremal tool to clean up the terminal that melted because of arching.

 

They make a special lead wire kit that has a red, blue and black wire lead with a special terminal end on each wire specifically made to connect to partially damaged compressor terminals.   I did a quick search before finishing this post - it looks like they are available in 3 different wire sizes, (8, 10 or 12 gauge).

 

Here's a site that has all 3 wire gauge sizes - http://www.hvacbrain.com/Term-LOK-3-Wire-Compressor-Terminal-Repair-Kits-s/4422.htm

 

Amazon has them also - here's one listing that has a good detailed picture of the special connector ends.

http://www.amazon.com/Qwik-QT2810-QwikLug-Compressor-Terminal/dp/B003LL9W4A

check the similar products list below description for different wire gauges.

 

Here's a YouTube video, make sure you get the style that the set screw comes down from the top, the cheaper kits have the set screw coming in on the side and may not be able to tighten good.

 

They have them listed at APP but show as not available, but with all the above info you should be able to find a set for your needs.

Part number: QT2810

Part number: QT2812

Edited July 13, 2014 by Budget Appliance Repair

[m_west5]

Thanks Willie for covering my 6. I did guestion to myself Fred's second post about the terminal names he used compared to his first post, but didn't put it together. No excuses, just my not paying attention to the details.

With that being said Fred, please follow Willie's advice above. It's right on the money.

[fred_perkins]

Many thanks to both of you for the suggestions and advice!  It really wonderful to have the brainpower of multiple pros.

 

I wondered myself whether those terminals might just be going directly into the compressor and not a capacitor first.  Sure enough, I looked around and found the capacitor hidden in a nearby location (behind the control panel and main circuit board).

 

Glad to know about the special clamp-on lead kits for situations just like this.  I had no idea that such a product exists and probably would not have found them on my own.  I plan to order a kit soon -- or, if available, maybe just a single connector (since R & S are fine and show no signs of damage).

 

When the unit is unplugged from the wall, I assume there is the same risk of shock via these leads since they run back to the capacitor -- right?  So should I access the cap itself and touch a screwdriver between common and each of the other two cap terminals before cleaning the compressor terminal with a file?

[m_west5]

Yes, that is correct. Capacitors (and the wires still connected to the cap connections) hold a charge even when unit is unplugged. Safety first and foremost.

[Budget Appliance Repair]

I believe the only way your are going to get just a single one of those repair wires is if you find a used one on Ebay, I'm pretty sure as new they are only sold as a complete set of three.

[fred_perkins]

I bought the lead wire kit and replaced the common lead using the nifty new connector.  I got the brand that was recommended (with brass screw that tightens from above rather than from the side).

 

The unit ran beautifully for two weeks after replacing the common lead/connector.  But then, just before noon today, the circuit breaker starting tripping.  Temps outside are in the mid-80s with a predicted high in the upper 80s later this afternoon.. 

 

The first time it tripped, I had to reset the main breaker (near the meter) for the entire apartment, in addition to the double AC breaker in our breaker box. Before powering up again, I pulled the AC unit from the window and exposed the compressor and newly-replaced common lead/connector. 

 

I then powered up and the fan started up and then I heard the compressor kick on.  A second or two after the compressor kicked on, the AC breaker tripped again (main breaker did not trip this time).  I noticed a moderate flash (like a big spark) that appeared to originate behind the compressor, close to the fan toward the back of the unit.

 

Does this sound like the compressor is shorting or grounding out?  Or more likely a bad cap?

 

Front and back coils were just cleaned a couple months ago, so I don't think dirty coils are causing an increased load. 

Edited August 5, 2014 by fred_perkins

[m_west5]

Hi Fred, how did the compressor and new lead look? Get a close look. You should start looking for the exact spark location. You will find it and then come on back and we'll go from there.

I would advise not to power on the unit until you find the sparked component to prevent further damage.

[fred_perkins]

The top of the compressor (where all 3 leads connect) looks clean.  There is no charring, residue, or other evidence of sparking anywhere near the new common lead/connector that was installed. 

 

As mentioned, the flash seemed to come from behind the compressor toward the back of the unit.  My fear is that the compressor is grounding out, so the spark is between the compressor housing and metal chassis -- but that's just my rookie guess.  I'm not really sure how to localize it without starting up the compressor again.

 

The unit has been running in "fan" mode (no cooling, so no compressor) for several hours without any problems.

[m_west5]

Ok, do you have a DVOM? Buy one, borrow one, you need one.

Unplug unit or switch breaker off. ALL resistance tests are performed with power OFF.

Resistance check all 3 compressor leads (remove wires from leads, check one at a time) to a bare metal spot on the compressor body.

Zero ohms or really low resistance = compressor bad.

Edited August 5, 2014 by beam current