MZD2766GEW Maytag wide by side Evaporator coil freezes up will not defrost

frankemilne

Premium Member
Joined
Apr 13, 2019
Messages
13
Location
Chino Hills CA
Model
MZD2766GEW
Brand
Maytag
Age
More than 10 years
Evaporator coil freezes up will not defrost. After manually defrosting unit cools properly until cool freezes up again, about 3-5 days depending on usage. Replaced adc board, defrost heater and defrost thermostat. Still will not defrost. Check resistance on heater and thermostat Pryor and after new installation and the old one actually seem to check out okay but change them anyway. Also performed ADC Board Test prior and after new installation and unit would not go into defrost after the L1 to test jump.

Old Parts actually checked out okay accept both control boards would not make unit go into defrost after jumping. Otherwise unit comes to temperature shuts off and Cycles beautifully until the coils freeze up which restricts air flow to the refrigerator consequently lowering that temperature slowly until total freeze up and then manually defrosting again. I am stumped at this point the door seals are good there's no sweating it just won't defrost any help would be appreciated at this point thank you.

Also have been reading through your blogs and have noticed that this is a very common problem with this unit but have not been able to find any resolution please help thank you.
 
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rickgburton

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Try this:
Open the doors for a period of time (5-10 min) to force the control to call for cooling).

Cycle the cold control on and off three times in six seconds. The cold control needs to be left in the closed (calling for cooling) position for the defrost system to energize on all platforms. It is not enough to cycle the cold control knob, the contacts must actually open and close . In most cases, you can hear the contacts open and close if they are doing so.
 

frankemilne

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Apr 13, 2019
Messages
13
Location
Chino Hills CA
My Maytag wide by side has two sliding temperature controls on top of one another one for the freezer and one for the refrigerator. Do I cycle both refrigerator and freezer on and off or just the freezer as it is the only one with an off position.

Also I have an ammeter hooked up to the unit and when running it is only drawing 9 tenths of an amp and only increases when the ice is cycling or the doors are open and the lamps are on fyi.

Also may I open the doors while the unit is already running and still leave it open for 5 to 10 minutes or? Must I wait until the unit has come up to the temperature and everything shuts off before proceeding with this test.
 

frankemilne

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Messages
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Location
Chino Hills CA
Ok, did the off on off on off on in the 6 second interval. After the first off unit did not react to anything. After 2 minutes refrigerator attempted to fire up drawing 13.2 amps and shut off in 2 seconds. 2 minutes later refrigerator attempted to start again and now I have a 1.1 amp draw. after the initial attempt the fans continued to operate and still are at this point.

But apparently no defrosting of the coils as they are freezing up as we speak. it appears as the cooling system is functioning as well to the best of my knowledge without pulling the refrigerator out and actually checking compressor fan etcetera but I can hear it and feel the air coming out under the refrigerator as well as the interior. Does the temperature control have any bearing on defrost?

It is the only thing I have not replaced I hate to keep throwing money at this bird but a new reefer right now is not in my budget. As if they ever are,lol. Still stumped.
 

frankemilne

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Apr 13, 2019
Messages
13
Location
Chino Hills CA
Coils are iced up again restricting proper cooling to refrigerator and freezer. Freezer has jumped up to 10 degrees Fahrenheit and the refrigerator is up to 50 at this time. I am manually defrosting again to save my food. Fortunately I have a backup freezer in the garage and coolers for refrigerator items. What the heck?
 

frankemilne

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Messages
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Location
Chino Hills CA
I was trying to add a photo of what the condenser coils looked like before defrosting after 5 days. I don't know how to achieve this or if it's possible.
 

frankemilne

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Location
Chino Hills CA
Ok, you must be in an Eastern Time Zone got it. Going to fire up my defrosted unit and I'm sure it will function once again perfectly until coils freeze up. Wow it's like being in The Flintstones LOL should be a simple fix you would think. But I have heard nothing but bad things about this Maytag unit unfortunately. I have old refrigerators in my shop that run forever granted they are not energy efficient but they are cost-effective because they always work!
 

rickgburton

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Do you have the evaporator cover installed or removed? If it's removed it won't cool properly. You have already replaced the entire defrost system so I think we need to see some pictures of the frost pattern on the evaporator coils. Leave the machine plugged in and running while you remove the evaporator cover and take several pics of the frost pattern. Make sure the pics are on your computer. Click on the picture icon in the toolbar. Then "select file" and navigate to your pics. Click on open then "upload files".

Measure the voltage across the red wire and the white wire on the ADC. Should be 120 VAC. If you have an amp meter, clamp the yellow wire. If not that's ok. Make sure the machine is plugged in and running. Use a screwdriver to short L1 to TEST and hold it for several seconds. Listen for a relay click then measure the voltage across Yellow wire and the white/black wire, 120 VAC.
 

frankemilne

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Location
Chino Hills CA
Evaporator covers are installed. Voltage across red and white wire reads 120. Shorting L1 to test has no effect can't hear any relay clicking and there is no voltage across yellow wire and white black. I have a photo of the Frosted up coils but I'm using my smartphone and unfortunately I'm not smart enough to put the picture in this blog. But I could email it Direct if that is possible. Thanks again.
 

Jake

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Rick did you know they stopped production of that defrost control board?

Here's the defrost control board for his model: 61005988 Defrost Control Board

frankemilne: Yes, it's your defrost control board that is faulty, if your defrost thermostat and defrost heater ohm test good, that's all it can be is a bad defrost control board.

Jake
 

frankemilne

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Messages
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Location
Chino Hills CA
Okay, thanks. I will contact the seller. I am curious about the placement of the defrost thermostat it is an inch and a half away from the back wall as the manual States and is on the line without what I believe is the dryer? It's something with some Putty wrapped around it in a little piece of copper tubing coming out of it. Anyways it's not on that line. Also would like to show you the pics of the frost patterns on the coils. I am using an Android phone to do this blog. Do you know how I can take a picture from this device and add it to this blog so you can look at it? Thanks again Jake.
 

frankemilne

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Messages
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Location
Chino Hills CA
Also while I'm waiting for a functional board I was wondering instead of shutting down the refrigerator and manually defrosting this couldn't I jump the heater for the approximate 23 minutes manually so as to confirm the heater is actually functional and to save me from playing with the hair dryer and taking everything out and apart? I understand that you would by no means advise anyone to do such a thing because of safety but I work with a lot of electrical devices and I'm confident with my skills.
 

rickgburton

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As long as I know the correct wires to jump of course.
You already tried and it didn't work:
frankemilne said:
Shorting L1 to test has no effect can't hear any relay

Jumping, shorting, same thing.
As long as you can read continuity through the heater and defrost thermostat they should work fine.
 

frankemilne

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I don't understand are you saying that if I apply direct voltage to the defrost heater and thermostat circuit without the defrost control board it won't work?
 
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