, this built in refrigerator was cooling properly, but the customer noticed the strip that separates the freezer from the fresh food section was very warm to the touch. The temperature seemed to be warm sometimes, and very warm at other times. It didn't seem like to big a problem until the white plastic strip began to yellow from the heat so it was time to have it looked at.
Side by side refrigerators consist of the two cooling cavities that are temperature isolated from each other by a divider. The front of this divider called the mullion will have part of the refrigeration sealed system run just bellow the surface where it will provide a bit of warmth to help prevent condensation from forming between the doors. As cooling demands change, the temperature of the mullion strip will change and may become more noticeable during times of warmer outside temperatures. If the strip becomes noticeably warm or even hot to the touch, this is an indication the sealed system is unable to efficiently remove heat from the unit and it needs to be addressed. This can be something as simple as cleaning the condenser coils and grills with a cleaning brush
to allow for better airflow. But it can also be an indication that something has failed.
The most likely cause of a warm mullion strip is the failure of the condenser fan. This fan, which is located near the compressor, is used to draw cool air across the condenser coils, and the compressor to aid in removing heat from the system. If the fan motor were to stop due to a failure or by possibly getting blocked, the sealed system would be unable to remove most of the heat causing the mullion strip to be very warm to the touch.
On this unit, I removed the top grill and access cover, and found just what I expected, a stalled condenser fan motor. A quick check with my meter showed no voltage to the motor, so using the tech sheet, I put the unit into a diagnostic mode to test the motor components. When I selected the condenser fan test, I still was unable to read any voltage to the motor which is an indication of a source voltage failure. Or in this case, the control board is not providing any power.
After shutting off the power and removing the control board from it's housing, I installed a new control board
into this unit. Turning the power back on brought the display and interior lights to life, but the compressor and fans were not working. A bit of information on these built in refrigerators. There is an approximate 8 minute delay used by the board for their start up routine. The best thing you can do is turn them on and wait. Once it is ready, everything will start up as usual and begin cooling again. This goes for anytime the power is shut off to the unit, so don't panic when changing this board, or after turning the power back on. With everything back in place, and 8 minutes had elapsed, the fans kicked back on, and the mullion strip was back to it's normal temperature.