How to Troubleshoot Cooling Problems in a Whirlpool Top Mount Refrigerator

Escrito Por: Ben Schlichter
  • Comentários: 0
How to Troubleshoot Cooling Problems in a Whirlpool Top Mount Refrigerator

Dificuldade

Moderate

Passos

12

Tempo necessário

No estimate

Introdução

If your Whirlpool top mount refrigerator is freezing food in the fresh-food section or not cooling enough, the problem is often related to airflow, thermistor readings, the control board, or (less commonly) a sealed system issue. This guide shows how to do the basic checks, access the cold control assembly, identify the correct thermistor wires, and test the thermistors with a multimeter on Whirlpool models like the WRT31, WRT51, WRT53, and MRT1188 that use Athena or Hercules control boards.

    • Check whether the refrigerator section is over-cooling (freezing food) or not cooling at all (or only cooling a little).

    • Treat both symptoms seriously because the same sensing and control parts can cause either problem.

    • Unplug the refrigerator and pull it away from the wall so you can safely access the back.

    • WARNING: Live voltage tests require power, and they can shock you if probes slip or touch the wrong points.

    • Remove the rear access panel to expose the black condenser coils.

    • Brush and blow the dust and dirt off the condenser coils using a condenser coil brush or forced air.

    • Don’t skip this because dirty condenser coils can prevent proper cooling even if every other part is good.

    • Remove the glass shelves from the refrigerator section to make room to work.

    • Use a 1/4 inch nut driver to remove the two 1/4 inch screws from the cold control housing.

    • Pull the cold control assembly out far enough to access the wiring and the board.

    • You can access the housing with the unit plugged in, but unplug it before disconnecting connectors or doing resistance tests.

    • Press the plastic retaining tabs inward and slide the control board out of the housing.

    • Use a wide putty knife to press the tabs if a flathead screwdriver doesn’t fit well.

    • Give yourself enough room to reach the test points and connectors on the board and harness.

    • Locate the thermistor wires in the harness connected to the control board.

    • Use the orange and blue wires as the refrigerator thermistor pair.

    • Use the gray and pink wires as the freezer thermistor pair.

    • Both thermistors use the same resistance specifications.

    • Unplug the refrigerator so you can safely measure resistance.

    • Disconnect the thermistor wires from the harness or connector so you’re not reading the control board through the circuit.

    • Use a multimeter in resistance mode to measure across the orange and blue wires for the refrigerator thermistor.

    • Measure across the gray and pink wires for the freezer thermistor.

    • Compare your readings to a Whirlpool thermistor temperature-to-resistance chart for the temperature the sensor is currently at.

    • Plug the refrigerator in only if you’re doing a live voltage test.

    • Set the multimeter to DC volts and probe the thermistor wires at the harness to check for the expected 5 VDC signal.

    • Use very fine multimeter probe leads because the connector area is extremely tight on these housings.

    • Keep probes from touching each other or any other terminals to avoid shorting the board.

    • Replace a thermistor if its resistance is far out of specification for its temperature.

    • A bad thermistor can cause no-cooling or over-cooling because it sends the wrong signal to the compressor to run too little or too much.

    • Test both thermistors because either one can affect the system’s cooling behavior.

    • Look for ice around the edges of the freezer rear panel or coming out of the air holes.

    • Pop off the small screw covers and use a 1/4 inch nut driver to remove the hidden 1/4 inch hex-head screws holding the panel.

    • Remove the ice maker cover by taking out its Phillips screw.

    • Disconnect the ice maker Molex harness by pressing the bottom and top retention tabs back using a flathead screwdriver or needle-nose pliers.

    • Pull the evaporator cover off, or steam away heavy frost with a garment steamer if the panel is frozen in place.

    • Treat heavy ice encasing the evaporator area and foam as a likely defrost problem, such as a bad defrost heater or a bad sensor.

    • If ice is only on the foam assembly but not on the silver coils, inspect the plenum area for obstructions that block airflow to the refrigerator section.

    • Clean the foam and steam away any ice blocking the air paths, then reseat the foam assembly.

    • Check that the evaporator fan runs normally because a stalled or slow fan can cause poor cooling and ice buildup near the fan.

    • Use the freezer thermistor location behind the evaporator cover as an easier place to test it with a multimeter if needed.

    • Inspect the evaporator frost pattern and look for a uniform frost across the entire evaporator coil as the normal pattern.

    • Suspect a low-charge sealed system issue if frost is heavy only on the inlet segment, such as the upper right evaporator line frozen solid.

    • Use a clamp meter on a compressor wire, such as the white wire, to check compressor amperage during a cooling run.

    • Use about 1 amp as a reference for normal operation on this style of unit, and treat readings below about 0.6 amps as a strong sealed system warning sign.

    • If the frost pattern is normal and the thermistors test in spec, consider the Athena or Hercules control board as a possible over-cooling cause.

Conclusão

Reinstall all covers, reconnect every harness you unplugged, and secure panels with their original screws. If the condenser coils are clean and the thermistors test correctly but the frost pattern or compressor amperage suggests a low-charge condition, plan for professional sealed system service.

Autor(a)

Ben Schlichter

Membro desde: 21/01/25

6447 Reputação

0 comentários