I looked at a customers 3 year old upright Frigidaire freezer tonight that wouldn’t cool down past 12 degrees. But the temp. setting was set at 0 degrees. I removed the cover from the evaporator coils and they were slightly iced up about 2 inches along the bottom. I defrosted the coils and checked the heater and defrost thermostat. Both checked out okay. Then using the controls on the door I put the freezer into defrost manually. Just to make sure this function was working properly. This also checked out okay. My question is, with the ice built up on the evaporator coils, why isn’t the freezer defrosting itself? Could there be an issue with the control board on the door? Or something else? What tells the freezer it needs defrosting? Any help would be greatly appreciated. Thanks.
Here is a link to the tech shet and manual from Frigidaire.
http://www.frigidaire.com/manuals
Here is a good link to get manuals
http://appliancedigest.com/index.php?
You have to join the site to download the manual but it is free and this is a very good site for manuals.
There are several manuals for freezers in the Miscellaneous Service Manuals section.
Sounds more like a low freon problem than a defrost problem to me.
For defrost to effect cooling the coils must be iced/frosted over to the point that the evaporator fan cannot pull air through them.
Low freon would give cooling on only part of the evaporator coil.
If you are confident that it is a defrost problem then I would say that the control board is toast. I think the display and control board are one and the same on this unit but cannot find a parts breakdown to confirm this.
AP4981913
Thanks denman. The owner had the manuals for the freezer. They weren’t much help. The owner told me 2 weekends ago he had a repairman look at the freezer and the evaporator coils were completely iced over.Top to bottom. The repairman defrosted the coils and left. He didn’t check anything else. If the evaporator coils were completely frosted over, the freon level should be okay. Correct? This all started when the other repairman installed a 3 in 1 start relay instead of installing the correct start relay. Later that night when he went back was when he realized the evaporator coils were completely frosted over. Yesterday when I looked at the freezer they had just started to ice over along the bottom. So the control board along with the heater and defrost thermostat are the only components that control the defrost cycle? Nothing else in the freezer/evaporator section? Maybe this freezer has multiple issues. Thanks again denman.
If the evaporator coils were completely frosted over, the freon level should be okay. Correct?
Correct
Later that night when he went back was when he realized the evaporator coils were completely frosted over.
Hard to comment on this as you did not see the coils or know what/how the repair was done.
If the unit had the doors open for any length of time it will fill with warm moist air so when it is re-started I would expect a fair amount of frost on the coils until the interior humidity is reduced.
For defrost to be a problem the coils must be frosted/iced up to the point where the evaporator fan cannot pull sufficient air through them to cool it.
So the control board along with the heater and defrost thermostat are the only components that control the defrost cycle?
Yes
Nothing else in the freezer/evaporator section?
You do have a thermistor for temperature control but that does not seem to be a problem here.
I think it may be in the freezer itself.
My evap coil is icing over too. much older model though. sealed system. How could it be low on coolant? no signs of corrosion. Ice sensor?
rwomer
Please start your own post using "Post New Topic"
Give a description of the problem and any symptoms and or troubleshooting results you have found.
Also include a model number.
http://www.appliancepartspros.com/modelnumber_locator.aspx
How could it be low on coolant?
If the coils are evenly coated then it will not be a low coolant problem.
If iced/frosted over to the point where the evaporator fan cannot pull air through them then it is probably a defrost problem. But without a model number I do not know if it even has a fan or auto-defrost.
no signs of corrosion.
Low freon does not need ant signs of corrosion to occur.
Ice sensor?
Do not know what you are referring to.