Hi,
Ok, there is no defrost heater on the fresh food evaporator coil, only the freezer evaporator coil has the defrost heater. This is a very complex dual evaporator cooling system with the 3-way involved.
This how it works:
If the refrigerator compartment is calling for cooling the control determines if the refrigerator evaporator coil temperature has been above a predetermined temperature (approximately 35°F) for 15 minutes. This is to assure the evaporator coil is
defrosted.
- If the evaporator coil is below the predetermined temperature the refrigerator fan turns on to circulate air over the evaporator coil to defrost it. The fan will operate until the evaporator coil is above the predetermined temperature for 15 minutes.
- If the evaporator coil is above the predetermined temperature but for less than 15 minutes the refrigerator fan turns on to circulate air over the evaporator coil to defrost it. This continues until the 15 minute time is met.
• When the evaporator coil is above the predetermined temperature for 15 minutes or more the 3 way valve moves to the closed position. At the same time the compressor, condenser fan, refrigerator evaporator fan turn on.
• With the 3 way valve still in the closed position the compressor evacuates the refrigerant from the low side of the system and pumps it into the high side of the refrigerant system.
• After a predetermined time (approximately 2 minutes) the 3 way valve changes position allowing refrigerant to flow from the high side, through a capillary tube, and into the refrigerator evaporator coil allowing cooling of the refrigerator compartment.
The refrigerator evaporator fan also turns on and circulates air across the evaporator coil. Heat is removed from the air and recirculated back to the compartment.
• When the refrigerator temperature cools below the control setting it will either:
- Turn the compressor, condenser fan, and evaporator fan off and switch the 3 way valve to the open position.
- Or, if the temperature in the freezer compartment is above the control setting or is within a predetermined amount from the cut in temperature the 3 way valve changes position allowing refrigerant to flow from the high side, through a capillary
tube, and into the freezer evaporator coil allowing the cooling of the freezer compartment. The freezer evaporator fan also turns on and circulates air across the evaporator coil. Heat is removed from the air and recirculated back to the
compartment.
So if the refrigerator evaporator fan is running, and you moved the the thermistor to the proper position, and put the control board in 8 hr defrost instead of ADC, then I really don't have a clue why it's still frosting up your refrigerator evaporator coil. Unless there is a problem with that 3-way valve sticking and allowing the refrigerator evaporator coil to get a CONSTANT flow of refrigerant through it and not closing that 3 way valve to the refrigerator evaporator after the temperature in the refrigerator has been satisfied.
I'd suggest having Whirlpool come out to see if it is that 3-way sticking open for the refrigerator evaporator coil.
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Jake