WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is a temperature‑actuated defrost thermostat designed for use on refrigeration evaporator coils.It is a small, mechanically simple sensing switch – typically a bimetallic, normally closed device with a mounting clip - that opens it’s contacts when the local coil temperature rises to the thermostat’s specified setpoint (55 degrees), thereby interrupting the defrost heater circuit.
Inside the appliance the defrost thermostat is part of the defrost system: it is indeed mounted directly to the evaporator or evaporator sheath with the supplied clip so it senses coil temperature accurately, and it controls current to the defrost heater while interacting with the defrost control (timer or electronic control board). When the evaporator is cold the thermostat remains closed allowing the control to energize the heater during a defrost cycle; once the ice has melted and the coil temperature reaches the thermostat’s setpoint the thermostat opens and de‑energizes the heater, preventing unnecessary heater run time and reducing risk of heater overheating or component stress. It thus affects defrost duration, ice build‑up, and downstream compressor/fan operation by helping maintain normal evaporator function.
In this article you will learn how the WR50X55 operates electrically and thermally, wich appliance locations and models typically use this style of thermostat, common symptoms of failure (such as persistent ice build‑up, heater that never shuts off, or a defrost heater that never comes on), basic troubleshooting steps using a multimeter and temperature manipulation, and practical replacement considerations such as matching setpoint, terminal type, mounting clip fit, and electrical ratings. The guidance is focused on providing the technical facts a technician, engineer, or informed appliance owner needs to diagnose, test, and replace the part safely and with the correct specifications.
table of Contents
- Function and Role of the Defrost Thermostat in GE Refrigerator Defrost Control Systems
- How the WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip Operates Within the Evaporator assembly
- common Electrical and Thermal Failure Symptoms and Diagnostic Indicators
- Replacement Considerations, compatibility Notes, and Step‑by‑Step Installation for the WR50X55 Defrost Thermostat
- Q&A
- In Summary
Function and Role of the Defrost Thermostat in GE Refrigerator Defrost Control Systems
The WR50X55 GE Refrigerator Defrost thermostat 55 Deg with Clip is a temperature-actuated switch that directly controls the defrost heater in GE refrigerator defrost control systems. It is indeed a normally closed sensor mounted to the evaporator with a clip so the sensing bulb reads coil temperature; during a defrost cycle the thermostat conducts current to the heater while the coil remains below its 55°F opening setpoint,and it opens as the coil warms to interrupt heater power.Because the thermostat is wired in series with the heater, it provides a temperature-limited cutout that operates independently of cycle duration in both mechanical timer and electronic-control defrost schemes.
Functionally and diagnostically, the defrost thermostat shoudl show near-zero ohms continuity when cold and an open circuit after the sensing element warms past the setpoint; technicians verify operation by measuring continuity at low temperature and after heating the bulb. Compatibility considerations for replacement include matching the 55°F setpoint, terminal type and lead length, and ensuring the clip locates the bulb against the evaporator plate-incorrect placement or a different setpoint can produce incomplete defrost or premature cutout. common failure modes are welded-closed contacts (heater remains powered during defrost), open contacts (no defrost and excess ice buildup), and intermittent contact (partial defrost cycles); correct part selection and proper bulb placement restore intended behavior in both mechanical and electronic GE control systems.
- Diagnostic checks: cold continuity (closed) → OK; warmed continuity (open) → OK; stuck closed → heater overrun; stuck open → frost accumulation.
- Replacement notes: match setpoint, terminal style, lead length, and clip mounting location for reliable operation.
| Item | description |
|---|---|
| Setpoint | Opens at approximately 55°F to terminate defrost |
| Type | Normally closed temperature-actuated switch |
| Mounting | Clip-mounted to evaporator plate for direct temperature sensing |
| Electrical behavior | Near-zero ohms when cold; open circuit after warming past setpoint |
How the WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip Operates Within the Evaporator Assembly
The WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is a temperature-actuated, bimetal switch designed to monitor the evaporator coil and interrupt the defrost heater when the coil warms to approximately 55°F. Mounted with a spring clip for direct thermal contact to the evaporator tubing or fin, the thermostat is normally-closed at low temperatures and opens at its setpoint to break the heater circuit during a defrost cycle.In typical systems the thermostat is wired in series with the defrost heater and the defrost control (timer or electronic control); the control starts a defrost,the heater raises the coil temperature,and the WR50X55 opens at ~55°F to terminate heating and prevent excessive warm-up of the evaporator and nearby components.
Proper operation depends on secure mechanical mounting and good thermal coupling: the metal clip ensures the sensor follows coil temperature rather than air temperature in the cabinet. Technicians validate function by checking continuity at cold temperatures (closed) and loss of continuity once the sensor warms past the setpoint (open). Common service symptoms tied to this part include persistent frost buildup on the evaporator (thermostat stuck open or clip loose) or shortened/aborted defrost cycles (thermostat opening prematurely). Replacement compatibility is generally limited to models specifying WR50X55 or equivalent thermostats with a 55°F opening characteristic and clip mounting; confirm the control wiring and physical mounting match the original before replacing.
- Setpoint: ~55°F (opens at setpoint)
- Switch type: Normally-closed at low temperature, opens on warm-up
- Mounting: Clip-on to evaporator tubing or fin for conductive sensing
- Role in circuit: In series with defrost heater and control to terminate defrost
- Failure symptoms: Continuous frost (open), shortened defrost (premature open), loose clip causes incorrect readings
| Item | Description |
|---|---|
| Setpoint | Opens at approximately 55°F to terminate defrost heater |
| Sensor type | bimetal thermostatic switch, clip-mounted for direct contact |
| Function in system | Limits defrost duration by opening heater circuit when coil is warm |
Common Electrical and Thermal Failure Symptoms and Diagnostic Indicators
The WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is a temperature-actuated switch that completes the defrost-heater circuit while the evaporator coil is cold and opens once the coil reaches the thermostat’s trip temperature (approximately 55°F / 13°C). Mounted with the supplied clip to the evaporator fins, the part senses coil temperature directly; correct seating and thermal contact with the coil are essential for reliable operation. In service, the thermostat presents a low-resistance path when cold (closed) to allow the defrost heater to run and should become an open circuit as the coil warms to the trip point, so failures commonly manifest as either a permanently open device that prevents defrost or a permanently closed device that allows excessive heater operation during defrost intervals.
- Excessive frost buildup on the evaporator while compressor cycles normally – thermostat likely fails open (no continuity when cold).
- Water pooling beneath the evaporator or excessive melting during defrost – thermostat may be stuck closed or not making proper contact with the coil.
- Intermittent defrosting or inconsistent defrost cycles – poor clip contact, corroded terminals, or marginal switching behavior.
- Multimeter shows continuity at room temperature or no continuity in ice-water – indicates failed thermostat; expected behavior is closed in cold test and open when warmed above the trip point.
| Item | Description |
|---|---|
| Trip temperature | Approximately 55°F (13°C) |
| Typical cold-state resistance | Near 0 Ω (closed contact) |
| Typical warm-state indication | Open circuit (OL) once above trip temperature |
| Mounting | Metal clip to evaporator fins – requires firm thermal contact |
For practical diagnostics, always disconnect power before handling or removing the thermostat. A simple functional check is to clamp the thermostat to a cold surface or immerse the sensing end in an ice-water bath and measure across the two terminals with a multimeter: you should see continuity when cold and an open circuit after warming above the specified trip temperature. If continuity behavior is correct but frost problems persist,verify heater continuity and defrost-timer or control operation; if the thermostat shows incorrect continuity behavior or poor mechanical contact to the coil,replacement with the WR50X55 GE Refrigerator Defrost Thermostat 55 Deg with Clip is the appropriate corrective action.
Replacement Considerations, Compatibility Notes, and Step‑by‑Step Installation for the WR50X55 Defrost Thermostat
The WR50X55 GE Refrigerator Defrost thermostat 55 Deg with Clip is a bimetal temperature switch used in the defrost circuit to protect the defrost heater and regulate defrost termination.This device is a normally closed switch at low evaporator temperatures and opens at approximately 55°F (≈13°C),interrupting power to the heater as the coil warms; technicians should expect continuity at temperatures below the rating and an open circuit above it. Typical failure modes include a thermostat that fails to close when cold (resulting in no defrost) or fails to open during defrost (causing heater to run continuously), so verify resistance/continuity with a multimeter and confirm terminal style, clip fit, and physical orientation against the existing part before replacement.
Compatibility depends on both electrical and mechanical fit: confirm the terminal type (spade/push-on), mounting clip diameter, and the refrigerator model’s wiring scheme rather than relying solely on part number lists, sence some GE/Kenmore models use variant clips or harness adapters. replacement procedure is straightforward but requires safe handling: disconnect mains power, access the evaporator area, remove the old thermostat from the coil and note wire positions, check the new thermostat for the same temperature rating and switch polarity, mount the clip securely to the coil so the sensor body contacts the metal, reconnect the wires, restore power, and validate proper defrost by initiating a manual defrost or observing the next automatic cycle; if the heater still behaves incorrectly after replacement, investigate the timer/controller, heater continuity, and door/gasket issues as the next troubleshooting steps.
- Disconnect power before servicing; verify with a meter.
- Check continuity: closed at cold, opens near 55°F.
- Match terminal style and clip size to existing installation.
- Mount sensor body flat against evaporator tubing for accurate sensing.
- Retest by forcing a defrost cycle or monitoring normal cycle behavior.
| Item | Description |
|---|---|
| Temperature Rating | Opens around 55°F (≈13°C) |
| Switch Type | Normally closed bimetal switch |
| Common Symptom | No defrost or continuous heater operation |
| Installation Note | Use matching clip and ensure firm contact with evaporator tubing |
Q&A
What is the WR50X55 defrost thermostat and what does it do?
The WR50X55 is a temperature-sensitive safety switch used on many GE-style automatic defrost refrigerators. It is clipped to the evaporator coil and senses coil temperature during a defrost cycle. It is normally closed at low (cold) temperatures and opens when the coil warms to its rated temperature, cutting power to the defrost heater to prevent overheating.
The part says “55 Deg” - is that 55°F or 55°C?
“55 Deg” for this defrost thermostat refers to about 55°F (approximately 13°C). This is the approximate temperature at which the thermostat opens during defrost to stop the heater.
how can I test the defrost thermostat to see if it’s working?
Always disconnect power first. Remove the thermostat from the evaporator (or access it in place) and use a multimeter set to continuity or resistance. At freezer (cold) temperatures the thermostat should show continuity (closed). You can verify by chilling it in ice water – it should be closed. Gently warm it (hair dryer, warm water) and it should open (no continuity) once it reaches near the trip temperature. If it does not change state, it is faulty.
What symptoms indicate the WR50X55 thermostat may be bad?
Common signs include heavy frost/ice buildup on the evaporator, a freezer that ice over and causes poor cooling in the fresh food compartment, a fast-cycling compressor, or failure of the defrost heater to turn off or turn on. If the thermostat is stuck open the heater may never run (causing ice buildup). If it is indeed shorted/failed closed during a defrost board malfunction the heater may overheat (rare if other safeties are present).
How do I replace the WR50X55 thermostat (basic steps)?
Turn off and unplug the refrigerator. Access the evaporator by removing the freezer back panel. Note or photograph the wire routing and clip position. Unplug the thermostat connector or cut power leads if necessary, remove the retaining clip, and unclip the sensor from the coil. Install the new thermostat in the same location and orientation, secure with the clip, reconnect the wire harness, reassemble panels, and restore power. Do not overtighten the clip or place the sensor where it won’t be in direct contact with the coil.
Is this thermostat compatible with my GE/Hotpoint/Kenmore refrigerator?
WR50X55 is an OEM GE-style defrost thermostat used on many GE/Hotpoint/Kenmore models, but compatibility depends on the refrigerator model and harness connector. Always confirm using your refrigerator model number and the part number listing from a trusted parts supplier or the appliance’s service manual before ordering.
Can I reuse the original clip and wires or should I replace them too?
You can reuse the original clip and wiring if they are undamaged and provide secure contact. Inspect the clip for corrosion, broken pieces, or weak springs; replace it if it won’t hold the sensor firmly to the evaporator. Also check the connector and wires for burned insulation or corrosion and replace any damaged components to ensure reliable operation.
Is it safe to operate the refrigerator if the defrost thermostat is missing or temporarily disconnected?
No. Operating the refrigerator without a functioning defrost thermostat (or with it disconnected) risks improper defrost operation. If the thermostat is open or missing the heater may not run and the evaporator can ice up, causing cooling loss. If wiring is altered incorrectly it could allow the heater to run without control, creating a fire or leak risk. Replace the part before returning the appliance to normal service.
In Summary
The WR50X55 GE refrigerator defrost thermostat with a 55-degree trip point and mounting clip is a small but critical component of the appliance’s defrost system.By monitoring evaporator temperature and closing the circuit when frost conditions exist, it enables the defrost heater to run onyl when needed, helping prevent excessive ice buildup, maintain cooling efficiency, and reduce wear on other refrigeration components.
Accurate diagnosis and judicious replacement are essential when defrost problems arise. Symptoms such as persistent ice accumulation,inconsistent cooling,or an inactive defrost heater should prompt testing of the thermostat (continuity checks at the specified trip temperature),inspection of the clip and sensor seating,and evaluation of related parts such as the heater,timer,and control board. Replacing the thermostat only when testing indicates a fault-and using the correct part and proper installation technique-minimizes unnecessary expense and restores reliable operation.
Maintaining and,when necessary,replacing the WR50X55 thermostat with its clip helps preserve defrost function,energy efficiency,and overall appliance longevity. When in doubt about diagnosis or installation, consulting the refrigerator manufacturer’s guidance or a qualified service technician ensures safe, effective repairs and continued 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
.
