Window AC - Bad Cap, Cutoff, or is Compressor Toast?

4 years ago

I'm hoping someone with repair knowledge can offer some input on a inoperable Window AC unit.

Quick version. 2 year old 10,000 BTU Kenmore (apparent LG Components) has full power and working fan, but the compressor will not engage. A video of the symptoms is here: https://vimeo.com/419645674

Does it seem like it's simply a bad capacitor, maybe a bad thermal cutoff switch, or is this symptomatic of a dead compressor?

More detail: Unit is a Kenmore Elite 77101. It was just over a year old and hadn't even been through 2 summers yet when the problem started

Symptoms: Full power and apparent function - Fan runs and the panel acts like it's working properly, but compressor will not engage. There's a very faint "tick" sound (relay?) and what seems to be a change in power level to the fan for a few seconds, then the the fan resumes full power (in the video you can even see the fan speed change as the compressor tries to engage) I'm assuming this is the start relay trying to engage the compressor, but when it can't it stops trying.

I have tried a suggested technique of tapping the compressor with a rubber mallet as it tries to engage with no effect.

There were no issues leading up to this. No freezing. No drop in output, no odd noises, no apparent cycling issues. Just a sudden realization that the room was hot and that the compressor wasn't on. It had been hot the few days before it stopped working, high 80's to low 90's with high humidity, but nothing it hadn't handled before.

In general the unit was not overworked though. I'd even kept the thermostat set at 78 to keep power use down and to keep from over working the unit. We would usually turn it to just fan at night and open windows when it cools down, but it had been on the cool setting for over a full 48 hours. Even that doesn't seem like it should stress the unit that much though.

We tried power cycling, and even left it unplugged overnight with no change.

I'm trying to decide if it can be reasonable repaired, or if I need to look for a replacement before it starts getting unbearably hot (in either case, I don't think I'll ever buy Kenmore or LG anything again).

Any input is greatly appreciated. THANKS!

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Comments (5)

dadoes
4 years ago
Could be a bad capacitor. Could be a locked compressor. Could be a wire burned off. Maybe a bad start relay.

Not a bad thermal cutoff ... that's what's repeatedly shutting off the compressor (and on when it cools sufficiently) from trying and failing to run.

The fan slows during the start attempts due to overall increased current draw and amperage draw.

77101 is not a full model number. The correct number is on a model/serial label affixed somewhere on the unit. Probably syntax of xxx.xxxxxxxxx (three digits, a period, and more digits/characters).
K. Black thanked dadoes
K. Black
Original Author
4 years ago
last modified: 4 years ago
Dadoes, thanks for the reply. The full model number seems to be 580.77107710. I'll have to get to the box later to confirm.

After looking at parts numbers and comparing the control layouts, I'm pretty certain that the Kenmore is actually a re-badged LG Model LW1017ERSM. Same slide out chassis. Same remote.

Sadly, a significant number of the 2 and 3 star amazon reviews (21%) mention a similar, if not identical issue. Maybe now that I know a more widely sold identical model. maybe I can manage to better narrow down a fix.

I'll have to open the box up again to check the part number, but capacitors only tend to be around $35-$40 from what I can tell. Maybe I'll give that a shot. On the other hand, from what people are describing it doesn't sound promising, so maybe that's $40 better put toward a different brand that won't maybe just fail again in a year.
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kevinande
4 years ago
Window units are not exactly designed to be worked on, especially in the modern world of throw away appliances. Some may disagree with me, but given their cost it makes far more sense to simply replace it unless you just want to tinker with it. Certainly hiring someone to do the work is not worth the cost. Back when I was a young whipper snapper we had three units in our country home that were all 220V and they lasted for years. I seen to remember my dad complaining a lot about the electric invoice too lol.
K. Black thanked kevinande
dadoes
4 years ago
Surprising ... the model number does search at SearsPartsDirect.com.

They list the capacitor at $26.95. Possibly can find it for less. And perhaps better to shop parts elsewhere, Sears is notorious for advising *after* placing an order that items are out-of-stock/backordered or even NLA.

It's a combination start/run compressor/fan capacitor. Can't quite read all of the rating info, the item photo has it turned to the right. But, 270VAC, 50/6.0 uF ... something, something, etc. Match whatever's on the original.

Capacitors can be tested with a meter if you have one and know how. Also can visually examine if it appears "swollen," burned, or the vent cap is blown.
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K. Black thanked dadoes
K. Black
Original Author
4 years ago
" It's a combination start/run compressor/fan capacitor" -- Ahhh, That explains it. I could only find a fan start capacitor on the LG site.

" Capacitors can be tested with a meter if you have one and know how ". I do have a good Fluke multi, watched a few videos, and I'd toyed with the idea of testing it as I was putting it away for the winter, but I haven't messed with high voltage Caps before and didn't have a way to safely discharge it. I'm wondering if it will still have a significant charge after 7+ months. I can make a discharge tool, but that also entails extra cost, even if I'm just buying heavy gauge wire and figuring out what size resistor to use.

I didn't find any scorching or signs anything was blown, as I recall. No telltale swelling either, but it may have been in a sleeve that I didn't feel comfortable messing with at the time.
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