[brianday]

My Tappan refrigerator is freezing foods & liquids even at the lowest temperature settting. I did keyword search the posts prior to posting this post.

Per another website, I checked the temperature control by checking continuity with my multimeter, with the switch set to coldest and off. With the multimeter set to 20K ohms, when the setting is off, it reads infinity (1). When set at the coldest setting, it reads continuity 0 (same as touching the 2 probes together). The temperature control passed the continuity test. When I repeat the test with the multimeter set at 200 ohms, the alarm sounds for continuity. It sounded at the coldest setting and no alarm for the off position.

I then checked the defrost timer using my multimeter to test continuity. There are 4 posts with "3" being the common (white). According to the website, I put one probe on the common post (3) and tested the other 3 posts. One or two of the posts should read 0 or near 0 (continuity) and the third post should read infinity (1). With the multimeter set at 20K ohms, post 2 read infinity (1), but post 4 and 2 read 12.60, rather than 0 (continuity). I then advanced the timer to the defrost cycle and repeated the test. Again 1 or 2 posts should read continuity, but one of the posts that previously read continuity, should now read infinity. This time post 4 read infinity (1) and posts 2 and 1 read 12.61. If I set the multimeter at 200 ohms (as during the temperature control test) I should have an alarm sound when there is continuity. No alarm sounds at any post whether in defrost cycle or not. The defrost timer does advance while the refrigerator is operating. Should I consider the defrost timer to be bad, where I did not get a 0 reading (indicating continuity) even though it advances? Is it possible my defrost timer is different and should not have continuity? Should I be looking at another cause for why my refrigerator is running cold?

Thank you for any assistance.

[woodchuck]

The fridge is too cold so too much cold air is coming through the vent where the cold air is blown from the freezer by the evaporator fan in the freezer. To control this flow you have a damper which is closed more when you select a higher temp for the fridge. Check this damper and vent.

[brianday]

Thanks woodchuck. Can you tell me if the damper is controlled mechanically or electronically? i.e. Does the temperature setting adjust the amount of the opening of the damper via a switch? From what I can gather, the evaporator fan and damper control are at the back of the fridge. The problem fridge is in our rental apartment. I won't be able to get back up there until tomorrow. From what you say, the damper is not closing enough to block the flow of cold air into the fridge compartment. What are the typical reasons for the damper remaining open too far? Thank you again for your help. This is all very new to me.

[woodchuck]

Based on this diagram part #2 is your control knob. MRT15DREW Parts List

I think yours is a mechanical control. You turn the knob to adjust the damper. It could have a broken plastic part or missing spring. You'll have to take some apart to find the problem. There could just be blockage preventing it from closing. Check the freezer side of the vent also.

[brianday]

Thanks again woodchuck for your last reply. I removed the housing over the fan and damper to see if the damper was broken or stuck. It was fine and turns freely. The fan spins freely. I closed the damper completely to keep the coldest air in the freezer and the refrigerator froze even harder. Doesn't make any sense, but that's what it did. The thermostat checked out, the defrost timer advances and I closed the damper. What's left to try and or replace? Any chance that the limiter (defrost) thermostat is malfunctioning causing it to run longer than it should?

[woodchuck]

Does your compressor turn off when the temp controls are set for the warmest setting. Can you check the temp in your freezer.

[brianday]

The compressor does shut off. When I was up there yesterday doing work on other things, the refrigerator seemed to run very little. I checked the temperature today and it has been steady @ 25.7 Fahrenheit for a half hour now. Thanks for your help.

[brianday]

Hi again woodchuck. Update: My remote thermometer stopped working not too long after I last updated the temperature a day and a half ago. When I went up and retrieved it today, it was reading 1 degree. So it is much colder than what I originally thought. Don't know if this affects what you think the problem is.

[woodchuck]

5 to 10 degrees is normal for most freezers. It sounds like it may be your cold control. Refrigerator Repair Guide: How To Test the Temperature Control (page 2 of 2) - ACME HOW TO.com Even if it checks out ok on the test it is acting like it is not adjustable. Here's diagram and parts list part 18. MRT15DREW Parts List

[brianday]

Part #18 is just the knob of the temperature control, isn't it? Wouldn't it be part #21 or 21A depending on which model, Partselect.com - Frigidaire Refrigerator Parts And All Brands of Appliance Parts
or
Partselect.com - Frigidaire Refrigerator Parts And All Brands of Appliance Parts
My model fridge doesn't have a 0-6 to indicate which specific model #. Here is the label on the fridge, is it a MRT15DREW3? http://mohairdollwigs.com/tappanfridge.jpg

I did test the temperature control, so apparently the test isn't conclusive then. This was in fact the website I used to run the test. Thanks.