WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is a temperature‑activated defrost thermostat (a bimetal temperature switch) designed to sense evaporator coil temperature adn change state at approximately 55°F (≈13°C). The part combines a temperature sensing element and a mounting clip to secure the device to the evaporator or refrigerant line; electrically it is typically a normally‑open or normally‑closed snap‑action switch that interfaces with the defrost control circuit. As a discrete temperature controller it is compact, usually has two spade terminals for wiring, and is specified by its actuation temperature and physical mounting method rather than by complex electronics.
Inside a frost‑free refrigerator or freezer the defrost thermostat monitors coil temperature during a timed defrost initiated by the defrost timer or electronic control board. When the evaporator is below the thermostat setpoint the switch changes state to permit power to the defrost heater during an active defrost cycle; as the coil warms above the setpoint the thermostat opens (or returns to its normal state) to remove power and prevent overheating. The component thus interacts directly with the defrost heater,the control module or timer,and indirectly affects compressor and evaporator fan cycling by ensuring frost is removed without allowing sustained heater operation.
In this article you will find a technical description of the WR50X55 function and specifications,guidance on model compatibility and mounting orientation,common failure symptoms and diagnostic checks (including continuity testing at temperature and expected resistance/continuity behavior),troubleshooting steps to isolate thermostat faults from heater or control failures,and practical replacement considerations such as correct setpoint,clip placement,terminal type,and safety precautions when servicing the defrost circuit. The focus will be on providing data useful to technicians, engineers, and experienced appliance owners for accurate diagnosis and safe replacement of the defrost thermostat.
Table of Contents
- Function and Role of the Defrost Thermostat in Refrigerator Defrost Cycles
- How the WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip Operates Within the Appliance
- Common Failure symptoms: Thermal, Electrical, and Mechanical Indicators
- Compatibility, Replacement Considerations, and Clip‑Mount Installation Procedures
- Q&A
- Key Takeaways
Function and role of the Defrost thermostat in Refrigerator Defrost Cycles
The defrost thermostat is a temperature-actuated safety and control device that monitors the evaporator temperature during a defrost cycle and interrupts the defrost heater circuit once the coil has reached the designed termination temperature. The WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is a mechanical bimetal snap-action thermostat set to open near 55°F; it is mounted directly to the evaporator using the supplied clip so the sensing element tracks coil temperature rather than air temperature. In typical automatic defrost systems the timer or control board supplies power to the heater, and the thermostat opens when the coil reaches the setpoint to terminate heat and prevent overheating or prolonged defrosting. Proper thermal contact via the clip and correct orientation affect timing – a loose or poorly seated sensor will delay opening and can cause liquid water on the floor or excessive cabinet temperatures.
Functionally the thermostat acts as both a control input and a safety cutoff: closed at cold evaporator temperatures to allow the heater to operate when commanded, and open at warmer coil temperatures to stop the heater. Common diagnostic checks use an ohmmeter – the thermostat should show continuity when the coil is cold and open after warming above the setpoint; alternatively, warming the sensor with a heat gun while observing continuity replicates normal operation. Typical failure modes are a stuck-closed thermostat that lets the heater run too long (leading to warm cabinet and potential compressor stress) or a stuck-open thermostat that prevents defrost heating (resulting in heavy frost buildup and reduced cooling). Practical verification and replacement require matching the setpoint, mounting clip style, and lead configuration to the original part to ensure compatibility and reliable defrost termination.
- Symptoms of a failed thermostat: freezer warm or water pooling (stuck closed), excessive frost and poor cooling (stuck open).
- Test method: continuity cold = closed, warm above ~55°F = open; test in situ with the clip secured to the coil or remove and simulate temperature with a controlled heat source.
- Replacement note: match setpoint and clip style for accurate thermal coupling to the evaporator.
| Item | Description |
|---|---|
| Setpoint | Opens near 55°F (termination temperature) |
| Mounting | Clip-on sensor for direct evaporator contact |
how the WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip Operates Within the Appliance
The WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is a bimetal temperature switch designed to monitor evaporator coil temperature and act as a high‑limit for the defrost heater circuit. Installed with its spring clip directly to the evaporator tubing, the device is normally closed at low coil temperatures so the defrost heater can be energized by the control module; as the heater warms the coil the bimetal element opens at the 55 Deg set point, interrupting current to prevent overheating and excessive melting. This mechanical action provides a predictable, line‑voltage safety cutoff independent of the electronic control board, and the clip mounting ensures fast thermal response and repeatable operation across GE refrigerator models that specify WR50X55 as the replacement part.
Functionally, the thermostat is a two‑terminal passive switch used in series with the defrost heater; compatibility depends on matching the 55 Deg opening set point and the clip style so that the sensor senses the same coil temperature as the original assembly. Technicians commonly test the unit with a multimeter for continuity when the sensor is cold and for an open circuit after warming the element (bench heat or during a controlled defrost), and they replace it when continuity behavior does not change. Practical failure modes include a stuck‑closed thermostat that allows the heater to run longer than intended or a stuck‑open thermostat that prevents the heater from operating, both of which produce symptoms such as persistent frost, iced evaporator surfaces, or abnormal water during the drain cycle; replacing with a correct WR50X55 unit and ensuring good clip contact restores intended defrost timing and safety.
- Key features: 55 Deg opening set point, bimetal element, spring clip mounting, two‑terminal connection.
- Common symptoms of failure: continuous heater operation, incomplete defrost and ice buildup, or no defrost activity.
- Typical service checks: continuity at low temperatures,open circuit after controlled warming,and physical inspection of the clip contact.
| Item | Description |
|---|---|
| Set point | 55°F (≈12.8°C) opening temperature |
| Type | Bimetal defrost thermostat (mechanical) |
| Mounting | Spring clip to evaporator tubing for fast thermal coupling |
| Function | Interrupts defrost heater current when coil reaches set point |
Common Failure Symptoms: Thermal, Electrical, and Mechanical indicators
The WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is a bimetallic temperature sensor mounted to the evaporator coil that controls the defrost heater by switching the heater circuit based on coil temperature. Functionally the device is normally closed at low coil temperatures to allow current to flow to the defrost heater, and it opens at the rated temperature (approximately 55°F / 13°C) to interrupt the heater once ice has melted.Proper compatibility requires matching the mounting clip,lead length,and terminal type so the sensor senses coil temperature accurately and interfaces reliably with the refrigerator’s defrost timer or control board.
- Thermal symptom: evaporator remains heavily frosted while the defrost heater never energizes – typically caused by a thermostat stuck open or thermally detached from the coil.
- Electrical symptom: no continuity at cold temperature or intermittent contact – indicates burned contacts, internal corrosion, or broken leads.
- Mechanical symptom: detached or broken clip, crushed sensing element, or corrosion on terminals - produces false readings or failure to actuate.
Diagnose the part with safe, standard tests: remove power, isolate the thermostat, check continuity with a multimeter when the sensor is cold (expect continuity) and verify it opens when warmed (e.g.,with a controlled heat source); inspect the clip engagement and lead insulation for damage. Also confirm the defrost heater receives voltage from the controller during a manual defrost – if the controller supplies power but the heater does not run, the thermostat or its connections are the likely fault. For replacement, match the temperature rating, clip style, and terminal configuration to maintain correct thermal contact and circuit behavior; the following rapid reference summarizes the key technical attributes.
| item | Description |
|---|---|
| Rated trip | Opens near 55°F (≈13°C) |
| Switch behavior | Normally closed at low temperatures; opens on warm-up |
| Mounting | evaporator coil clip |
| Common failures | Open-circuit, high resistance, mechanical clip failure |
Compatibility, Replacement Considerations, and Clip‑Mount installation Procedures
The WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip senses evaporator temperature and terminates the defrost heater circuit when the coil rises to its cutout, approximately 55 °F. Mechanically it is a two‑terminal temperature‑actuated switch that is normally closed at freezer temperatures and opens as the sensed metal temperature reaches the setpoint,interrupting current to the defrost heater to prevent overheating. Compatibility depends on matching the electrical connection style and the thermal cutout: the replacement must use the same clip‑mount sensor, spade terminal configuration, and 55 °F cutout to behave correctly in a GE defrost sequence or in refrigerators that use the same sensor geometry and control timing.
When replacing and installing the clip‑mount thermostat, prioritize sensor placement and secure thermal contact so the device reads the evaporator metal rather than air temperature. Typical practical steps are: remove power, confirm the old thermostat’s behavior with a multimeter (continuity cold, open above cutout), unclip without damaging the sensing element or capillary, attach the replacement clip to the same coil location or tubing with full metal contact, and reconnect the spade terminals before restoring power and observing a defrost cycle. Follow-up checks include verifying that the defrost heater runs untill the thermostat opens near 55 °F and that wiring routing keeps the thermostat clear of moving parts and moisture buildup.
- Key checks: match cutout temperature, clip orientation, terminal type, and ensure good metal-to-clip contact.
- Diagnostics: use a multimeter to confirm continuity at low temperature and opening when warmed to the cutout.
- Installation tip: seat the clip on a flat portion of the evaporator tube or fin and avoid compressing the sensing element.
| Item | Description |
|---|---|
| Temperature setpoint | Approximately 55 °F cutout (opens at or just above setpoint) |
| Switch behavior | Normally closed at low temperatures; opens to terminate defrost when warm |
| Mounting | Spring clip to evaporator coil or tubing for direct thermal contact |
| Terminals | Two spade/male quick‑connect terminals for series defrost heater wiring |
Q&A
What is the WR50X55 defrost thermostat and how does it work?
The WR50X55 is a GE OEM defrost thermostat (frequently enough called a defrost temp-sensor or bi-metal thermostat) rated at 55°F (about 12.8°C). It is normally closed when the evaporator temperature is at or below its rated temperature,allowing current to flow to the defrost heater during a timed defrost cycle. Once the evaporator warms above the rating, the thermostat opens and cuts power to the heater to prevent overheating.
How can I tell if the WR50X55 thermostat is bad?
Common symptoms include heavy frost/ice buildup on the evaporator, poor cooling in the freezer or refrigerator, running defrost heater continuously (ice melting continuously or water leaking), or no defrost at all. To confirm, test continuity with a multimeter: the thermostat should show continuity (near zero ohms) when cold (below ~55°F) and open when warmed above the rated temperature.
How do I test the WR50X55 defrost thermostat with a multimeter?
Disconnect power to the appliance, remove or access the thermostat, and set a multimeter to continuity or ohms. Cool the sensor (ice water or freezer environment) and check for continuity-meter should show continuity when the sensor is below ~55°F. warm the sensor (hold in your hand or use warm water/hair dryer carefully) and verify it opens (no continuity) when above the rating. If readings do not change with temperature, it is faulty.
Can I replace the thermostat myself and what are the installation steps?
Yes, if you are comfortable with basic appliance work and electrical safety. Steps: 1) Unplug the refrigerator.2) Remove interior panels to access the evaporator and the old thermostat. 3) Release the clip and remove the old thermostat from the coil/tubing, noting wire connections. 4) Install the new WR50X55 sensor with the clip so it makes firm contact with the evaporator coil (not insulated away from the coil). 5) Reconnect the wires in the same configuration, secure wiring, reassemble panels, and restore power. Always follow the appliance service manual and observe safety precautions.
Is the WR50X55 compatible with my GE refrigerator model?
The WR50X55 is a common GE/Hotpoint replacement defrost thermostat used in many models, but compatibility varies. Verify by checking the existing part number on your thermostat or consult the refrigerator’s parts list/service manual. If unsure, provide your refrigerator model number to a parts supplier or technician to confirm exact fit.
What temperature does “55 Deg” refer to, and in which state is the thermostat closed or open?
“55 Deg” refers to 55 degrees Fahrenheit (about 12.8°C). the thermostat is closed (allows current) when the evaporator temperature is at or below that setpoint, enabling the defrost heater during a timed defrost. It opens when the evaporator warms above the setpoint, stopping current to the heater.
Are there any installation pitfalls or tips to ensure reliable operation?
Key tips: mount the sensor in the same position as the original and use the clamp to ensure good thermal contact with the coil; do not place insulating material between sensor and coil; route and secure wires away from moving parts and hot surfaces; and always power off the unit before servicing. If the clip does not fit snugly, replace it with the correct style-poor contact can cause improper defrost control.
What happens if the defrost thermostat fails closed or fails open?
If it fails open (no continuity even when cold) the defrost heater will not receive power, causing progressive frost buildup, reduced cooling, and potential compressor strain. If it fails closed (stuck conducting), the defrost heater may run longer or continuously, perhaps causing excess thawing, water leaks, warm temperatures, or shortened heater life. Either condition requires replacement to restore normal defrost control.
Key Takeaways
The WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is a small but essential component that monitors evaporator temperature and signals the defrost system to stop when a specified threshold is reached. Proper operation of this thermostat helps ensure timely termination of defrost cycles, minimizes frost buildup on evaporator coils, and contributes to steady cooling performance and efficient energy use. The clip-mounted sensor design promotes secure contact with the evaporator, improving the accuracy of temperature detection and reliable cycle control.
Because a failing defrost thermostat can lead to excessive ice accumulation, uneven cooling, and increased wear on other system components, accurate diagnosis and timely replacement are significant. Testing and verification should confirm the thermostat’s function before replacing related parts; when replacement is necessary, selecting the correct WR50X55 GE refrigerator Defrost Thermostat 55 Deg with Clip and ensuring proper installation will help restore normal defrost operation. If there is any uncertainty about diagnosis or repair, consulting a qualified service technician is recommended to maintain safe and effective refrigerator performance.
Professional Appliance Service
If your appliance requires professional diagnosis or repair, visit
Revolff Home Services
for expert appliance repair services.
For local appliance service information see
Dryer repair Henderson
.
Replacement parts for many appliance models can also be found at
Reliable-Parts-Hub
.
