When I turn the ref. on after 3-4 days my evaporator coils covers with ice and my refrigerator is not cold. The freezer freezes though

As the freezer is working you can probably discount that the reason is low refrigerant gas. The other reasons would be that the fridge circulation fan has failed.
or
The channel that directs cold air from the freezer is blocked with ice at the rear of the freezer. It happened to my GE and was caused by a failed defrost timer that was icing up the evaporator coils at the back of the freezer.

A service call lasts about an hour including melting the ice with a heat gun..

There might be a few causes

Door Seal might be defective causing the door not to shut tightly this causes air from the room to get into the freezer through the opening and as the air comes in contact with the evaporator coils, it freezes. Normally the defrost system removes the ice but if the seal is defective the coils freeze too quickly and the defrost system cant keep up

If the freezer evaporator coils ice over, the defrost thermostat might be defective. Several times a day the defrost heater turns on for a few minutes to melt away any frost that may have accumulated on the freezer evaporator coils. In order for this to work, the defrost thermostat has to sense that the coils are cold enough. If the coils are cold enough the defrost heater will turn on. If the thermostat is defective it may not be able to sense the temperature of the coils and then won't turn on the defrost heater. If the defrost heater doesn't turn on, the evaporator coils ice over and eventually no air will be able to travel through the coils to provide cooling to the freezer. The defrost thermostat can be checked for continuity. It should have continuity when it reaches the low temperature of its operating range.

The drain in the freezer behind back lower panel
needs opening. You can see it at the bottom of the back panel
underneath the evaporator coils. (The cold coils)
Run Hot water in the drain until it clears or use a hairdryer.
When the defrost melts the water it goes down the drain
If the drain is clogged with Ice or ? The defrost water
overflows into the ref. or freezer or on floor
Run Hot water in the drain until it clears or use a hairdryer.
Also check fan undernearh Ref in the rear
Clean condenser coils underneath
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Leo Ponder
imufo2
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The drain in the freezer behind back lower panel
needs opening. You can see it at the bottom of the back panel
underneath the evaporator coils. (The cold coils)
Run Hot water in the drain until it clears or use a hairdryer.
When the defrost melts the water it goes down the drain
If the drain is clogged with Ice or ? The defrost water
overflows into the ref. or freezer
Run Hot water in the drain until it clears or use a hairdryer.
Also check fan undernearh Ref in the rear
Clean condenser coils underneath
.I'm including my article on Refrigerator Repair for your help and convenience.;
Please click or copy and paste into browser for Article
http://www.fixya.com/support/r5816737-fix_refrigerator_psychologically
Thanks for using fixya
Leo Ponder
imufo2
Please VOTE FOR ME IF THIS WAS HELPFUL

remove the access panel in the freezer section and see if the evaporator coil is iced over,a little frost is o.k.,but when they are covered with ice they can't pass cold air,if this is the case defrost the coil with a handheld hair dryer,then check the defrost heater under the coil for continuity,if its good then suspect a defective defrost control be it timer or adaptive defrost

If you only had ice buildup in one section of the evaporator you have a weak/inefficient compressor.
You need a new compressor or a new refrigerator.

1. Get the Food out of the Ref and Freezer. Unplug the power cord from the wall.
2. The cooling coil is in the back wall of the freezer side. Working from inside the Freezer.
3. Remove the back plastic cover to expose the cooling coil. It's called the Evaporator coil.
4. Use a hair dryer to melt all ice off the coil.
5. Put it back together. It should work for 3 - 5 days now at least.
6. Put a thermometer in there. After 24 hrs. the freezer should be 0 to 10 degrees F. and the Ref. side 37 to 44 degree F.
7. Check the door gaskets for tight fit, using a dollar bill for a gauge.
Shut the door on the dollar and try to pull it out in several places.

If it ices up again in a week or two, you have a defrost heater problem. There is a electric heat strip around the cooling coil. This heat strip comes on about 10 minutes every 8 or 10 hours. This heater melts the ice off the coil. There is a clock timer device under the ref. that cycles the heat strip. You may have a bad clock, fuse device or burned out defrost heater strip. The cooling coil must be ice free to work properly.

First, I think it’s important to know that the Ref side has no cooling coils, it’s basically a box and the cold air in the freezer is blown over by a fan through a channel into the Ref side. This channel has a door which regulates how much cold air goes through. You probably have two control knobs in the Ref side, one controls the temp with numbers 1-9, 9 being the coldest. This temp control tells the compressor how long to run. The other control is for that little door and it may have letters A-E, E being the coldest. If you set it on E (coldest) then this will close that little door and keep most the cold air in the freezer.
So, how can the Ref side be cold and the freezer side not freezing?

1. Coolant leak. There is enough coolant to keep the Ref side cool but not enough to freeze on the freezer side.

2. Defrost system failure. The coils on the freezer side are clogged with ice and it's just a matter of time when the Ref side won't cool either. The back wall in the freezer will be covered with ice/frost

First, I think it’s important to know that the Ref side has no cooling coils, it’s basically a box and the cold air in the freezer is blown over by a fan through a channel into the Ref side. This channel has a door which regulates how much cold air goes through. You probably have two control knobs in the Ref side, one controls the temp with numbers 1-9, 9 being the coldest. This temp control tells the compressor how long to run. The other control is for that little door and it may have letters A-E, E being the coldest. If you set it on E (coldest) then this will close that little door and keep most the cold air in the freezer.

Now, why is that cold air not getting over to the Ref side?
1. The little door is not open.
check your control setting. You can't see the door but, you should be able to feel air coming through the channel on the Ref side.

2. The fan in the freezer is not working.
You can hear this fan running when you open the freezer.

3. The coils on the freezer side are clogged with ice which won't let the fan circulate the air over to the Ref side.
This is a failure of the defrost system which consist of the defrost timer, heater, and thermo disc.

Also, If you replaced the evaporator fan then you got a good look at the cooling coils. Look at these coils while it is running. There should be a light coat of frost on all the coils. If this frost line is only 3/4 or 1/2 or any amount less than full coverage of the coils then the system has a coolant leak.

Directly under these coils is the drain pan and drain hole in the middle. This area should be clear of any ice or debris.

It could be some many things, to save time let me give you this check list:

• Check the temperature setting
• Assure that there is enough room for air flow in the refrigerator or freezer
• Check for air flow restrictions in vents
• Test the temperature control
• Clean the condensor coils
• Check the door seals
• Test the door switch
• Test defrost heater
• Test defrost timer
• Test evaporator fan
• Check for a clogged drain tube
• Check for refrigerant leak

Do what you feel qualified to do.

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