LRFCS25D3S refrigerator temperature fluctuating, freezer seems fine

[Consumerbot7237]

Model Number

LRFCS25D3S

Brand

LG

Age

1-5 years

This is a French door model, with ice maker in the freezer.

I've had a wireless thermometer installed to monitor the temperature in the fridge and freezer, and noticed that despite setting the fridge temperature to 37ºF, it was sometimes dipping down to 33ºF, at risk of freezing the contents.

In order to keep that from happening, I've since set it to 40ºF, and kept an eye on it. I've since seen it below 34. I've attached some charts that show the fridge and freezer temperature over the course of about 10 days. The spikes in freezer temperature correlate to brief periods of about 260 watts higher power usage, so I presume those are defrost cycles. I thought that might be the cause of the variations in fridge temp, but as the charts show, there doesn't seem to be a connection. In these charts, the fridge has been set to 40ºF, and the freezer to -4ºF.

On the second chart, Jan 29th, the temperature stayed between 33.8 and 35. That's actually wonderful, but as you can see, it doesn't stay there. If I change the set-point lower, I'm afraid of ruining the contents by freezing them. Is this normal behavior for this fridge? For all of them? Or is there a possible malfunction that could be fixed? I've got technical abilities with electronics, but would rather avoid doing anything that could jeopardize the warranty.

 

[Jake]

Hi,

I couldn't locate the service manual for this model, the problem is usually the refrigerator temp. sensor.

The only sensor I see on this model is the freezer temp. sensor: https://www.repairclinic.com/PartDetail/Temperature-Sensor/6500JB2002X/2651043 and I don't know if it controls the refrigerator section as well.

Hopefully another tech. or member that's seen and fixed this problem can shed some light on it for us.

 

[Consumerbot7237]

Thanks for that reply, @Jake !

Would you agree that a problem exists, then? If you look at that first chart, there's a brief period where it behaves as I'd expect would be normal, from the 27th at 4pm crossing into the 28th. The rest of the time it seems to be "hunting", but never finding equilibrium.

I thought I'd check here to confirm that something is actually off, prior to consulting with LG.

 

[Jake]

Normal would be 0 degrees F for the freezer and 37 degrees F for the refrigerator.

Your charts seem way too cold for the freezer being in the below 0 range. And not so far off in the refrigerator section. My refrigerator always hovers between 37 to 40 too depending upon door openings and defrost cycles, but never gets and stays above 40.

 

[Dan O.]

Where are you measuring the temperatures?

The controls are designed to maintain an average food temperature. If you're measuring right in the air flow, the readings will not be an accurate indicator of food temperature as the air temp will be colder whenever the compressor is running.

For food compartment temperature we put a container of water on a middle shelf and monitor that water's temperature.

For freezer temperature try elevating the temp sensor to the centre of the compartment and out of direct air flow.

Try that and see if the measurements change.

JMO

Dan O.

 

[Consumerbot7237]

Thanks @Dan O. and @Jake for the replies!

Your charts seem way too cold for the freezer being in the below 0 range.

The freezer was set to -4º (out of a possible range of -7 to +5). I'm not worried about the freezer getting too cold, unless it's a symptom of a problem.

The controls are designed to maintain an average food temperature. If you're measuring right in the air flow, the readings will not be an accurate indicator of food temperature as the air temp will be colder whenever the compressor is running.

The thermometer was positioned in a tray that should have kept it out of air flow. I'll put it in a sealed container, in the middle, to mitigate the issue you mentioned. I can't submerge the wireless thermometer in water, unfortunately.

Meanwhile, I tried setting the fridge to 35º, and it seemed fine. But while I was sleeping, it drifted down into the 20's, and some of my liquid contents had turned to slush by the time I caught it when I woke up. I've since set it back to 40º, and as before, it hung out there for a while, but eventually drifted down as low as 34.3.

I just checked the temperature of the contents with an infrared thermometer to compare. I got 35.3º, which jives pretty well with my wireless thermometer. (while set to 40º!)

The temperature swings end up being about 5º, and happen independently of our use of the fridge/freezer. (we're not filling it with hot food or slabs of frozen meat to defrost, for example).

I think I'll get in touch with LG, and see what they say. I'll try to remember to report back here!

 

[Dan O.]

I can't submerge the wireless thermometer in water, unfortunately.

If needed in the future, it could be inserted into a sandwich bag or balloon, etc. The thermal image should be fine however.

some of my liquid contents had turned to slush by the time I caught it when I woke up.

That's not right but I can't think of what might be responsible.

I think I'll get in touch with LG, and see what they say.

Hopefully it is a common occurrence and they know what the cause my be.

g/l

Dan O.

 

[Consumerbot7237]

They told me it didn't seem right, and suggested that I have a technician take a look at it. When I called a local tech, he was confused that LG hadn't opened a workorder for him. I didn't want to pay a service call/diagnostic fee, and never got around to asking LG to cut a workorder for him, until...

The other day, it completely quit cooling. The light came on when opening the door, fan noise resumed when the doors were closed. No errors reported on the controls, nor by the "Smart Diagnosis". My power meter showed that it was drawing 6-13 watts, which is normal idle draw when the compressor isn't running.

I now have a service call Wednesday to replace the compressor and/or control board. As before, I'll try to come back and share the outcome. Thanks again!

 

[Yankeefix]

LG LRFCS25D3S Refrigerator Service Manual