Evaporator freezes up

Delfield freezers have defrost in the control. It is a thermostat, defrost control, and other things all rolled into one device. Not adjustable in any way. check the manual for details. http://download.partstown.com/is-bin/intershop.static/WFS/Reedy-PartsTown-Site/-/en_US/manuals/6000XL%20SERIES_spm.pdf

If the refrigerator is not defrosting, the defrost control board might be defective. The defrost control board monitors several conditions and determines how often to run the defrost cycle. If the board fails, the refrigerator will not go into the defrost cycle. Eventually, ice will build up on the evaporator coil and then the refrigerator and or freezer will not stay cold enough. This will depend on where the evaporator is located. It's prudent to check the defrost heater and defrost thermostat for continuity before replacing the defrost control board.

Does it? Or is it just the display that reads 50? Don't forget the evaporator has to get to 50f to get rid of the ice forming on it. It will do this 3 or 4 times a day, but the product temperature should not creep much above setpoint. Check the food temperature with a digital probe when defrost occurs to see if it is only the display module ( which may have it's sensing phial too close to the evaporator or have lost it's insulation jacket)
Also check the grill in the base (condenser) is clear and clean so it recovers from defrost as it should..

Hi and welcome to FixYa, I am Kelly.
There are 12 midelos that fall under the model number you passed. I will cite EV171NYMQ05 as a reference model number via this link:
http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5140769

The freezer fan should be on anytime the compressor is on. If there is an ice block built up on the evaporator coils it can lock the fan blade in place via the ice build up. Additionally... if the fan motor bearings are dry or coated with sludge this too can prevent the fan motor from operating. The fan motor is item 3 this link: http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5140769&diagram_id=28174432#d28174432

Detail views:
http://www.appliancepartspros.com/Appliance-Parts/whirlpool-motor-evap-item-number-ap4539455.aspx

To check the can motor all that is required is a simple continuity check across the 2 connector wires. You should read under 480 ohms.

If you discover that the fan blades are encased in ice... do a manual defrost: (be ready to tend to a water mess)
1. By first unplugging the unit and then removing the freezer contents.
2. Direct an external fan into the freezer compartment for just over 2 hours.
3. Make sure the compartement drain funnel is clear of obstructions. Item 11 this link: http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5140769&diagram_id=28158051#d28158051

After the 2 hour manual defrost period plug in the unit and test to see if the fan motor is running.
If it is running you may have an automatic defrost problem causing the ice build up. On a freezer the ice build up will start again if there is an automatic defrost problem in 3 - 5 days. Until the automatic defrost problem is corrected you will end up doing the manual defrost routine described above everytime you have improper cooling problems.

Components that can cause the automatic defrosting problems are
1. The defrost timer item 7 this link: http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5140769&diagram_id=28257341#d28257341 Because it is not cycling or stuck in one position.
2. The defrost bi-metal thermostat item 9 above link (stuck closed)
3. The defrost heating element item 5 above link. (open)
And of course internal wiring....

Check the fan motor for continuity... if you attempt to lubricate it which is very difficult on this fan motor make sure you use paraffin based "Turbine oil" and not a regular household or automotive oil. Using any other oil will cause the fan to stop working in as little as 30 days.
Thanks for choosing FixYa,
Kelly

Dirty condenser, condenser fan motor is not running, freezer overpacked, bad thermostat, evaporator ice build up and it blocks the air flow. evaporator fan motor is not running or sealed system problem.

Defrost problem.

Check for excessive frost build up in the freezer on the back panel. This would indicate that you have a defrost problem. One of 3 things cause a ref not to defrost. Defrost timer may not be advancing to the defrost position on the timer...The defrost thermostat, located on the evaporator in the freezer, measures open (bad)...or you have a bad defrost heater. If you have an electronic defrost control,which is used on most Maytag, Jenair, or Amana units, this could be your problem. If you turn the unit off for 24 hours to let it defrost manually then it will last for about 2 weeks before freeze up again.

John,
What you are hearing is popping caused by thermal expansion inside the evaporator enclosure during its' defrost cycle.
Depending on your make and model, it'll go into defrost every 8 to 12 hours of compressor "run time". That is, the defrost timer "monitors" how long the compressor runs and after it accumulates the pre-set "run time", the timer then shuts the compressor off and initiates its' programmed defrost routine. This routine lasts for 20-30 minutes, or until the defrost thermostat opens.
The defrost routine sends 120 volts to a heating element in the evaporator compartment which gets red hot. This sudden temperature change (from below freezing to warm) causes the cabinet to expand slightly. That's when you hear the "Pop".

I hope this helps, John. Thanks for using FixYa, and don't forget to rate my answer.

SG

the drain pipe you cleaned out has a p-trap that holds water. after awhile this trap will build up sludge and possibly freeze up. i recomend defrosting the drain pan again and try some way to forcfully flush hot water thru the drain. I use a turkey baster filled with water to do this. if the drain continues to freeze you may need to install a heat trap to keep drain from freezing.
a heat trap is just a piece of 10-12 guage solid copper wire with about 3 inches in the drain and the other end wrapped around the defrost heater which is the BLACK rod attached to the bottom of the evaporator coil in the freezer compartment. if you need any further assistance just let me know Peyton

If its a frost free upright freezer and the evaporator is frosting up with a snow like frost you have a defrost problem.. defrost themostate, heaters, or timmmer