How to test & replace a defrost heater assembly with a bi-metal thermostat on an upright Frigidaire freezer

Get ready to save yourself some cash and hassle! If you need to find out if the defrost heater assembly or bi-metal thermostat is faulty on your upright Frigidaire freezer, you’re in the right place! You can replace it yourself if necessary, and we’re here to help you do it like a pro.

If you find out that you need any replacement parts for your Frigidaire freezer, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Important: The testing and replacement information in this article is based on model LFFH20F3QWC and may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

What you need

• Multimeter
• Phillips head screwdriver
• Flathead screwdriver

Important: The specific tools required may vary depending on the model of your appliance and the type of fasteners used on it. Always consult the user manual or refer to any specific instructions provided by the manufacturer for the recommended tools for your appliance model.

Read more: Freezer Section Too Warm: Top 6 Reasons and Fixes for Kenmore, Whirlpool, Frigidaire, GE, and Other Brands

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind:

• Always power off and unplug your appliance or switch off the circuit breaker before you attempt any maintenance or replacement work. This keeps you safe by eliminating any risk of electric shock.
• If the appliance has recently been used, give it plenty of time to cool down before working on it.
• Take your time while working to prevent accidents and personal injuries. Rushing is the enemy of precision.
• Work in a well-lit area so you can see and access appliance parts.
• Keep your workspace free of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with wet hands. Make sure the work area is completely dry.
• Check the user manual to see if there are specific installation or safety instructions related to your appliance or replacement part.
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause personal injury.
• Wear insulated work gloves to protect your hands from sharp metal parts and debris.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.
• Always take photos or make a note of wiring terminals or other connections before disconnecting them to make reassembly easier.
• Don’t test live voltage with a multimeter if you’re unfamiliar with how to prevent short-circuiting.
• Consider wearing safety glasses and/or a dust mask when working with chemicals, dust or a large amount of debris to prevent irritation or injury.
• Turn off the water supply at the outlet before beginning repairs. Keep towels ready to catch any residual water in the system when removing parts.

Read more:  Refrigerator or Freezer That’s Too Warm: Top 6 Reasons and Fixes

How to test the defrost heater assembly & bi-metal thermostat

Find out if your defrost heater assembly or bi-metal thermostat is faulty by following these steps.

Step 1: Access the defrost heater

1. Unplug the freezer from the power outlet.
2. Remove the shelves from the freezer.
3. Use a Phillips head screwdriver to remove the screws at the top, bottom, and two sides of the evaporator cover.
4. Carefully move the evaporator cover to the side and inspect the coils. If they’re heavily coated in ice and frost, then you’ll know that the unit hasn’t been going into the defrost cycle properly.

Step 2: Test the bi-metal thermostat

NOTE: Don’t remove the bi-metal thermostat from its clip on the evaporator coil.

1. Unplug the red and white wire connections from the thermostat.
2. Set a multimeter to continuity mode.
3. Use the meter probes to check the thermostat for continuity. Since the coils are likely iced up, the thermostat should be in the closed position.

If the thermostat is reading open or appears deformed, it’ll need to be replaced.

Step 3: Test the defrost heater

1. Set your multimeter to resistance (Ω) mode.
2. Use the meter probes to check the resistance across the connections of the defrost heater. You should get a reading of approximately 31 Ohms.

If you don’t get about 31 Ohms, then you’ll need to replace the defrost heater.

How to replace the defrost heater (if needed)

Follow these steps to change out the defrost heater in your Frigidaire freezer.

Step 1: Remove the old defrost heater

1. Make sure the unit is unplugged from the power outlet and disconnected from the water supply.
2. Unclip the bi-metal thermostat from the evaporator tubing.
3. Disconnect the two wire connections from the thermostat.
4. Find the two metal clips at the bottom of the evaporator coils.
5. Undo the two metal clips. Be very careful since the coil fins are very sharp,
6. Remove the two styrofoam blocks from each side of the heater.
7. Slide the old defrost heater assembly out.

Step 2: Install the new defrost heater

1. Slide the new heater assembly back into place.
2. Secure the heater to the bottom of the coils using the two metal clips.
3. Replace the two styrofoam blocks on each side.
4. Clip the new bi-metal thermostat into the same position as the old one.
5. Reconnect the two wire leads to the thermostat.
6. Replace the evaporator cover and secure it with the Phillips head screws.
7. Replace the shelves in the freezer.
8. Plug the unit back in and turn the water supply back on.

Read more:  Freezer Too Cold: Top 5 Reasons & Fixes

More for you

Thank you for reading! We hope this guide helped you get your upright Frigidaire freezer working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos.

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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