I'm having a problem with an evaporator icing up on my frigidaire PLRU1778ES0. This is a commercial stand alone fridge i.e. no freezer. Since we bought our house the fridge thermostat was turned to the warmest setting. I turned it colder day by day trying to get it cold enough. But even at coldest it doesnt get below 43, it stays there for a week and then quickly shoots into the 48-54 range once it finishes icing over . I force it into de-ice and the element worked all the way thru its defrost cycle. So i replaced the defrost timer and defrost thermostat and thawed the evaporator completely. The evap fan works beautifully and i replaced the door seal also as good measure since it had a tear in it. Ten days later here comes the problem again. Fridge is at 52 degrees. I have read that low refrigerant cannot cause this problem but what else could it possibly be??? This is my second figidaire that came with a house that has done this. The last fridge I replaced the ENTIRE defrost system on it except for wiring which i metered out and it still didnt stop it from icing over.

The ice is thicker along the bottom and up the sides but it has some ice from top to bottom and all the way side to side. The lines going to the coil are completely ice free. Now that i have the evap. thawed and the fridge has been running for 2 hours it got down to 36 degrees already. It's been a couple days and the temp is 40 degrees on coldest setting and the humidity in the fridge has been between 80-90% since I put it back together

As the compressor runs, humidity in the air inside the freezer condenses onto the surface of the evaporator. This frozen water on the evaporator is called condensate. The condensate will continue to build up on the evaporator over time, forming a white, fuzzy layer that periodically needs to be melted off during the automatic defrost cycle. During defrost, the compressor is turned off and a heater under the evaporator is fired up to melt the condensate off. As the condensate melts, it drips into the pan beneath the evaporator. Problem is that, in this particular design fluke, the defrost cycle ends and the compressor starts running again before all the water drains from the pan and, as a result, some of the water gets frozen. Next cycle, a little more gets frozen, and so on until the drain is blocked and the melted water starts backing up during defrost and running into the beer compartment below. You can visit at https://www.commercialfridgefreezer.com.au/