Temperature variation in freezer on Whirlpool...

Sorry, thought that was part of the post :)

ED22TQFXN00 is the model number from the serial plate. Built in 1998, side by side with water/ice in freezer door if that helps.

Nothing is blocking the vent. It's a Whirlpool. Ice seems to be normal, but ice cream is very soft. Ice cream sandwiches can be flattened easily.

I have caught it near 20 degrees several times today since I'm home. The digital thermometer records minimum/maximum temps, and if I reset it and check after 8 hours, min is around -5, the max will always be near 20 degrees even without me opening either the refrigerator or freezer side.

I'm attaching a picture of the model tag as well.

Thanks!

Are you thinking that this thermostat is intermittent? Both control knobs (I'm guessing for the thermostat) are in the refrigerator section. There does appear to be a removable panel that would give me access to this area.

I found an on-line source of parts with a schematic, I'll check there and see if it looks like what you're talking about. Seems to make sense though. The temp hit 21.6 max last night, so something would seem to be amiss with the thermostat...

I went ahead and ordered the thermostat and should have it by the time I go home today. I'll post back with the results in a day or two. Thanks!

New thermostat has been installed, now to see if it makes any difference! :) I'll reset the thermometer once it's cooled everything down again and see what my max temp is on the freezer after the replacement.

At first I wasn't sure the new thermostat was helping, but after everything had a chance to cool down I reset the thermometer and checked it this morning. The Min temp was -1.5, and the Max was 5.5, so it looks like the thermostat was probably the culprit. The ice cream sandwiches are also firm instead of squishy. I'll reset it again before I go to work and check when I get home, but I think it's fixed!

I guess I spoke too soon :(

Checked the thermometer when I got home, min temp of -2, max temp of 24F. Ice cream sandwiches are squishy again. Freezer and refrigerator were not opened at all.

Any idea what else might cause such strange behavior? I have already vacuumed off the coils underneath the refrigerator, are there any other coils that might be icing over? Defrost circuit on the fritz?

No worries, the thermostat was a likely culprit and was on my list of things to try and replace anyway. Don't feel bad at all!

I did open the back of the fridge and vacuumed off what I could. The compressor fan is definitely running. I also took off the evaporator cover in the freezer and checked the evaporator, there's no major buildup of ice on it like I thought there might be. The evaporator fan is running as well.

I repacked the items in the freezer so as to be sure there's plenty of airflow, especially to the air intake at the very bottom of the evaporator compartment in the freezer (it's behind a drawer).

I'm going to let it run again for a while after repacking and double-checking that nothing is blocking any of the ducts.

Thanks again for the assistance, and don't worry about the thermostat. Like I said, I was heading down that road anyway :)

A picture is worth 1,000 words. Didn't see any frost anywhere underneath it. The water drip tray had a little water in it but nothing much.

Left side (from rear)



Right Side (from rear)

OK, thanks for looking. I'll give it a bit to see if rearranging the contents and tapping on things behind the condenser panel might have made any difference before I throw in the towel :)

After doing some more reading, it seems like the temperature in the Freezer getting into the 20s might be normal, IF it's for a short time after the defroster heater kicks in. I guess I'd only be able to determine this if I could plot the temperature over time and see when, and for how long, the temperature is getting up into the 20s.

The min/max may be deceiving, since it could be getting into the 20s only once every 12 hours (defrost cycle) and for only a few minutes. That would be enough to fake out my thermometer, and may explain why last night it never got above 5 degrees.

I may just crank up the coldness in the freezer some more and let it go at that :)

I moved the thermometer to the refrigerator section and will see how consistent the temps are on that side.

Do you know how the defrost heater works on these models? According to the parts guide I found, it's a bi-metal defrost thermostat. I wonder if there's any chance that this thermostat might be bad, and is running the defroster more frequently or for longer than it needs to thus heating up the freezer compartment?

The thermometer for the fridge itself seems to measure the refrigerator side air, so if the defroster heater was running extra long it might not affect the temp on the refrigerator side as much.

I found this also in regard to a defective defrost mechanism:

Sometimes (but fairly rarely) both heater and cooling system can be energized by the timer at the same time. This can result in thawing then refreezing of food in the freezer compartment often leading to freezer burn on that food. In most cases the evaporator coil will remain mostly in an un-frosted state. The defrost heaters will cycle on and off as the defrost thermostat opens and closed due to the temperature it senses.

I did notice that sometimes after the compressor shut off, I could literally watch the temperature in the freezer compartment rise a degree a minute. I don't know how hot the defrost heater coil gets, but I wonder if that would explain the rapid rise in temperature I saw in the freezer if it were running excessively?

I THINK I FOUND IT!

I pulled the cover off the evaporator while the unit was running and measured the temperature of the heater coil and the evaporator coil with a non-contact infrared thermometer.

While the compressor was running, the evaporator coils were below zero, around -6 to -10 degrees, However, the heater coil was 40F! There's no way that coil would be 40 degrees unless it had power going to it, which as I understand it should NOT be happening at all when the compressor is running. That would also explain the rapid rise in temperature in the freezer after the compressor shuts off.

So it would seem to me that I've got a faulty evaporator heater circuit going on...

I ended up replacing the defroster timer, which seems like maybe it did the trick. It's been 24 hours since I replaced it, and the temps in the freezer have ranged from -3 to +5 degrees. Nothing into the 20s like it was doing before.

Thanks again for your help!