FIXED LDN22735 compressor making a buzzing noise until overload kicks it out

[Telkwa]

Model Number

LDN22735ST

Brand

LG

Age

More than 10 years

Figured it might be best to start another thread instead of tagging on to the previous. Especially since I was so wrong...

The 3 pins on the Embraco EGU 70HLC compressor are positioned two above, one below. Don't know how to identify start pin vs. run pin. Looking at the compressor, I started with the lowest pin at 6:00. 4.5 ohms to the pin at 10:00. 4.0 ohms to the pin at 2:00. 7.4 ohms across the two upper pins.

Scratched a little bare spot on the compressor body and checked pin-to-compressor. All of them showed 0.L. No continuity. Checked probe to probe several times just to make sure.

Put the overload device and starter relay back on the pins. Energized. The condensor fan spun up, then a little tick and a buzzing noise started. Sounded just like a stuck motor starter. Noise definitely from the compressor. The buzzing proceeded for 16 seconds, then the overload tripped. A few minutes later the logic tried to spin the compressor again. Overload tripped out at 14 seconds. 16 sec the next time.

I removed the starter relay and overload device. The o/l device was hot in one small area.

When we were trouble-shooting inside the house a few days ago the compressor wasn't buzzing, which seems odd. Why buzz now when it didn't a coupla days ago?

The compressor passes the basic pin continuity tests but buzzes instead of starting until the overload kicks it out. What does that mean?

 

[Telkwa]

When the fridge was still in the warm house the compressor didn't make the buzzing sound. Everything else - overload kicking out, etc. seems the same.

The fridge is out in the cold now - about 40 degrees or so. Could ambient temp have something to do with the compressor buzzing when it was quiet before?

I checked the start relay for continuity. Placed probes in the two pin sockets. Got 500 ohms. Does that seem OK?

I'll attach a pic of the start relay and overload device.

The start relay doesn't rattle. I gather that's not a good test.

Does a start relay fail completely? Or can it fail partially, causing the compressor to buzz and misbehave?

Also, a local repair person said the start capacitor hardly ever fails. Is that accurate? At this point I'm thinking about trying a new cap and start relay but not sure the symptoms point toward those parts.

 

[Jake]

Does a start relay fail completely? Or can it fail partially, causing the compressor to buzz and misbehave?

It completely fails and will not start the compressor at all.

Rick made this diagram that shows how to ohm test both the compressor start relay and overload:

If both ohm test good--->You need to contact LG, Your compressor is the problem, LG is notorious for this issue. Google search LG refrigerator compressors , you will see massive recalls for this issue.

 

[Telkwa]

Thank you very much for the response. And the graphic. Gonna print that out. Handy illustration for us newbs. It's very helpful to see a lot of information all laid out in one presentation rather than picking up bits and pieces.

When checking diagonally across the start relay I get 470 ohms. Not 3 to 12. Any thoughts?

I'm not sure which mode I should use for testing the start capacitor? I was using ohm scale. Got some value, don't remember what it was. Then I dropped the capacitor. Now I get open circuit. How do I tell if I broke it?

 

[Jake]

When checking diagonally across the start relay I get 470 ohms. Not 3 to 12. Any thoughts?

That's very odd, is you meter set at 20 ohms or the lowest ohms setting on your meter? You have fresh batteries in your meter? Are you sure that's not 4.7 ohms?

I'm not sure which mode I should use for testing the start capacitor? I was using ohm scale. Got some value, don't remember what it was. Then I dropped the capacitor. Now I get open circuit. How do I tell if I broke it?

That's not a start capacitor, that's a run capacitor, it doesn't make the compressor start.

Here's the run capacitor for your model: 0CZZJB2014L

Its best to use a analog meter to ohm test any capacitor.

Look here:

 

[Telkwa]

OK, sorry, I'm using the wrong terms here.

The broken LG has a run capacitor that's separate from the start relay and the overload device. I'd been calling that run capacitor a "start" capacitor because I thought the capacitor helped the compressor to start.

I bought a clamping multimeter a year ago but not up to speed with it. Got out the manual. Figured out how to test capacitance. The run capacitor is showing 12.1 uf. It's rated at 12 so I think we're good.

As far as the 470 ohms reading on the start relay - the new multimeter is auto-ranging so I just put the probes on the contacts. The meter showed M at first, then it scaled down to k, then it went to no multiplier at all and a reading of 470+- a few ohms. Pins 1 & 3 are diagonal to each other, as are pins 2 & 4. I get about 470 ohms across 1 & 3, and the same value across 2 & 4.

I triple-checked with an old Radio Shack analog meter and a tiny digital meter. All of them agreed that it was about 470 ohms when testing diagonally across the start relay.

You can barely see the "1" and "2" in my picture above. "3" and "4" are on the far side.

I attached a pic of the run capacitor. I came up with the same replacement part that you did. However, the replacement is not identical to the original. Notice the contacts are turned 90 degrees. The two terminals for the run cap are attached to a plastic bracket that holds them in the correct position to make up to the capacitor. I'd have to cut or modify to make it connect. Hopefully this is a moot point because our cap is OK.

 

[Jake]

I triple-checked with an old Radio Shack analog meter and a tiny digital meter. All of them agreed that it was about 470 ohms when testing diagonally across the start relay.

Then your compressor start device relay is bad.

Here's the compressor start device relay for your model:
6749C-0014E Compressor Start Relay

I attached a pic of the run capacitor. I came up with the same replacement part that you did. However, the replacement is not identical to the original. Notice the contacts are turned 90 degrees. The two terminals for the run cap are attached to a plastic bracket that holds them in the correct position to make up to the capacitor. I'd have to cut or modify to make it connect. Hopefully this is a moot point because our cap is OK.

A run cap is not necessary for the compressor to run properly. It's only purpose is it makes the compressor run more efficiently (saves energy over a year). It saves you about $1.50 a year in energy that's it.

 

[Telkwa]

The more I learn the more I have to unlearn (?) I thought the capacitor provided a little extra jolt to help the compressor start.

I think I'll take a chance and order the start relay.

Will report back with results. Thanks again

 

[Jake]

I thought the capacitor provided a little extra jolt to help the compressor start.

Nope.

I think I'll take a chance and order the start relay.

Yes, keep us posted.

 

[Telkwa]

What does that tell you if the resistance read diagonally across the start relay is nearly 500 ohms instead of 10'ish?

 

[Jake]

It means its bad for sure if your meter is reading it properly.

 

[Telkwa]

I needed four hands so my wife helped me take a picture.

Appliance Parts Pros sent me an email - start relay ready to be shipped.

Amazon was keeping track of my internet activity. I got an email from them showing dozens of start relays and overloads. The page was labeled "4.7 PTC Starter Relay". The overloads looked very similar to ours. Most of the start relays looked similar too but some of them only had two terminals.

Thanks again for your help and patience.

 

[paulhl]

For what it's worth I have a whole box of these, 3 terminal. I save them from SZ compressor replacements. Top left to cap, bottom or top right neutral from cap pigtailed to power neutral. Less than 6 ohms on the few I tested.

 

[Telkwa]

Thanks for the info, paulhl. Installed the replacement PTC. The fridge appears to be working. Put a tray of ice in the freezer section. We'll see what happens...

 

[Telkwa]

The water turned to ice. How do I mark this thread "Fixed"?

 

[Jake]

Glad to hear the new compressor start device relay(PTC) fixed it.

I marked it FIXED for you.

Thanks for the update!

 

[Telkwa]

Hey, quick update -
We put the LG back into service yesterday. Put a few small dings in the stainless steel front panel while bringing it back inside, dammit.
The Frigidaire that we bought in a rush to keep all the food from going bad is gonna have to go out into the garage I guess. We're not gonna run it, just store it.

My wife really likes the bottom freezer LG, so she's very happy to have it back in the kitchen. I got some points for fixing it. So, thanks for that!

Who knows how long it'll run before something else breaks but got our fingers crossed. It's already 15 years old.

I want to highlight this for anyone who stumbles onto this thread - I read on the internet (and was told the same by an appliance repair shop in town) that the PTC relay will rattle and smell burnt when it fails. That may be true in many cases, but not all. Ours passed the rattle/smell test but had failed.

 

[Jake]

I want to highlight this for anyone who stumbles onto this thread - I read on the internet (and was told the same by an appliance repair shop in town) that the PTC relay will rattle and smell burnt when it fails. That may be true in many cases, but not all. Ours passed the rattle/smell test but had failed.

Yes, that is true, it does not have to rattle or smell burnt to be bad, that's why ohm testing it is really the only way to know if its bad.