[Dbear13]

I'm having continuing problems with this. The fridge portion has been getting warm, and the vents are icing up (which undoubtedly explains why it's getting warm). I replaced both the adaptive defrost control unit (which I think tested bad, but I'm not entirely sure) and the defrost thermostat, but that didn't solve the problem. I finally took out the upper vent control entirely, so there's a clear passage up top. I've also de-iced the lower vent. But the fridge temperature is still hovering right around the low end of "spoilage" on the thermometer.

I checked yesterday, and the fan is running, at what seems to be a good speed. There was a little frost on the lower portion of the defrost heater, and some at the upper portion of the chamber that houses the defrost heater. But I don't know when it last defrosted, so that may be normal.

One other thing. The floor of the freezer compartment was covered with a sheet of ice, about 1/8" thick. I think we're spilling from the ice trays, since they're bending in the middle and inevitably some water slops over when we put them in. The ice wasn't covering anything, but I wonder if all that moisture isn't somehow contributing to the frost problem.

Any suggestions?

[magician59]

I would inspect the door seals to see if there are any gaps or tears that will allow warm air to leak in.

If there's ice on the floor of the freezer, the defrost is definitely working. You should look for a clogged or iced drain. You can usually thaw it by squirting very hot water into the drain, using a turkey baster, until you hear the water trickle into the drip pan. If it's clogged with something, you can usually clear the clog by pushing it through with a length of wire clothes hanger. Just make sure you put a small loop on the end of it so that you won't tear the drain tube.

[Dbear13]

I've looked at the door seals a few times, and I looked again last night, but I can't see any flaws. Would they be easy to spot?

[magician59]

Yes. For a significant amount of warm air to leak into the freezer or refrigerator, you will see a gap of at least 1/4 inch, or a tear, at least 3" long. If you don't see anything like this, you can pretty much rule out the gaskets as the cause of the problem.

[magician59]

Set the temperature controls at mid-range, and give the unit a day or so to stabilize. Then take the temperatures of the freezer and refrigerator. The freezer is supposed to be around zero degrees ; the refrigerator is best at about 38. Tell us what you find.

Also, feel the top of the dome on the compressor. Normally, it is warm, but not too hot to touch. The condenser (the coil next to the compressor) is normally a little too hot to touch next to the compressor, and somewhat cooler farther away from it.

The temperature of the evaporator coil itself is normally about -15 degrees; and there is normally a thin frost equally covering the evaporator coil.

Both the condenser fan and the evaporator fan will be running. All this is a picture of how it is supposed to look, when the compressor is running.

[Dbear13]

When I got home last night, the fridge temp was 50, with the thermostat turned all the way cold. (The kitchen temp wasn't much more than that.) I put the thermometer in the freezer section, and it was down around -20. And this is with the upper vent door mechanism out of the fridge, so the upper vent is just a big hole. That sure doesn't seem right. The lower vent was partly iced up (only a day or two after I last cleared it). I'm starting to think there's something other than ice physically blocking the lower vent.

[magician59]

Were the fans running? What about the other temperatures?

[Dbear13]

If you mean the fan in the back of the freezer and the fan underneath by the compressor, yes, I think so. When I went into the back of the freezer compartment the fan was running, and I can usually feel the air circulating in the back, although very little of it seems to be coming through the vent into the fridge. And I just checked the compressor fan and it's running.

What other temperatures do you mean?

[magician59]

If you're only seeing a partially frosted evaporator, you either have a partial restriction, or a leak somewhere in the system. It may be worth the cost to have a pro come in and diagnose it for you.

[Dbear13]

Well, I decided to fix the only problem I could find. The drain was in fact plugged (with an ice plug), so I got that cleared out. I set the thermostat just below the coldest setting, and we left for a couple of days. When we got back, the fridge temp was around 34, and there was no sign of icing on the vents. So maybe it's OK. I'll keep an eye on it, and like Ahnold, I might be back...

Thanks for hanging in there with this.