4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit is a combined electromechanical start device designed for single‑phase refrigeration compressors; it typically contains a start relay (or equivalent start device) and a thermal overload protector packaged to manage compressor starting and to protect the motor from overcurrent or overheating. as a discrete service part for Whirlpool refrigerators, the kit replaces the factory start components that provide the transient connection to the compressor’s start winding and an automatic disconnect if the motor draws excessive current or reaches unsafe temperatures.
Inside the appliance, the relay and overload work together with the compressor motor windings, the thermostat/control board, and the line supply to initiate compressor rotation and to interrupt power during fault conditions. when the control system calls for cooling,the relay provides a momentary or timed feed to the compressor’s start circuit so it can overcome initial inertia; the overload senses excessive current or temperature and opens the circuit to prevent winding damage. The assembly is normally mounted at or near the compressor shell and is therefore directly involved in the mechanical and thermal protection of the hermetic motor, making it a key component in the refrigeration system’s reliability and safe operation.
In this article readers will find a technical overview of the 4387535 kit’s function and its electrical and thermal role within the refrigeration circuit, guidance on model compatibility and specification matching, common failure symptoms such as no‑start, humming, tripping, or intermittent operation, and methods a technician or informed appliance owner can use to diagnose relay/overload faults. The article will also discuss practical replacement considerations – including rating and mounting concerns, verification checks to perform before and after replacement, and factors that indicate whether the start kit or the compressor itself is the root cause – presented in a professional, service‑oriented manner.
Table of Contents
- Function and Role of the Compressor Relay and Overload in Whirlpool Refrigeration Systems
- How the 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit Interfaces with the Compressor Motor and Control Circuitry
- Diagnosing Common Failure Symptoms: Electrical, Thermal, and Mechanical Indicators of Relay/Overload Fault
- Compatibility, Replacement Considerations, Step‑by‑Step Installation and Troubleshooting Procedures for Service Technicians
- Q&A
- The Conclusion
Function and Role of the Compressor Relay and Overload in Whirlpool Refrigeration Systems
The compressor relay provides the initial electrical connection to the compressor’s start winding and times that connection so the motor achieves sufficient torque to come up to speed, while the overload protector interrupts current flow if the compressor draws excessive current or exceeds safe temperature. The 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit combines a start relay and a thermal overload into a matched assembly so the relay’s engagement characteristics and the overload trip point are appropriate for the compressor motor; this reduces mismatch risks that cause repeated hard starts or premature motor stress. using the relay to apply the start winding only during the brief starting interval limits heating in the start coil, and the overload prevents damaging continuous operation under stalled or locked conditions.
- Typical failure symptoms: compressor hums but will not start, prolonged start times, or intermittent starting.
- Electrical indications: excessive starting current, blown fuses, or tripped breakers during attempted starts.
- Physical signs: discolored or melted terminals, cracked housing, or a relay that fails to click on energization.
| Item | Description |
|---|---|
| Function | Relay energizes the start winding; overload opens circuit on overcurrent/overtemperature. |
| Typical control voltage | 115-120 V AC for North American household models (verify on-spec for international models). |
| Compatibility | Designed for specific Whirlpool compressor families-confirm compressor part number and terminal layout before installation. |
In service diagnostics, technicians monitor starting current with a clamp meter and observe relay actuation; a relay that never engages or an overload that trips at low current points to component failure rather than refrigerant issues.For practical replacement, match terminal arrangement, mounting clip style, and electrical ratings; installing the 4387535 kit into a compressor for wich it was not specified can result in insufficient starting torque or nuisance trips.Do not bypass the overload to force a start-temporary bench tests can confirm relay operation, but long-term reliability requires a correctly rated relay and thermal protector matched to the compressor’s design.
How the 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit Interfaces with the compressor Motor and Control Circuitry
The 4387535 Whirlpool Refrigerator Compressor relay And Overload Start Kit provides the electrical interface between the refrigerator control circuit and the compressor motor by combining a start relay and a thermal overload protector in a compact assembly. The relay portion briefly connects the compressor’s start winding to the supply during initial energization (either via a current-sensing electromechanical relay, a PTC thermistor, or a solid-state start device), while the overload protector sits in series with the compressor common to interrupt power if the motor draws excessive current or the internal temperature of the motor rises beyond safe limits. On three-terminal hermetic compressors the kit wires to the Common, Start and Run terminals; the control board or thermostat supplies line voltage to the kit so the relay can apply the start winding for a short interval and then drop out as the motor reaches operating speed.
In practical service,the kit must match the compressor’s electrical characteristics (trip current/temperature,coil behavior and terminal layout) and the appliance’s control strategy,as incorrect ratings can cause repeated nuisance trips or failed starts. Typical troubleshooting cues for a failing start kit include repeated clicking, a humming compressor that won’t start, and elevated starting current on clamp meter checks; installation checks should confirm secure spade connections, correct terminal identification, and continuity through the overload when cold. Examples of useful diagnostic actions are measuring resistance between Common-start and Common-Run, confirming the overload opens under simulated overload conditions, and comparing nameplate ratings; replacement parts should comply with the compressor manufacturer’s specified electrical parameters.
- Common symptoms: clicking, humming without start, intermittent starts, or blown thermal protector.
- Key behaviors: momentary start engagement, series thermal protection, and dependence on control voltage source.
- Installation notes: match terminal layout and trip/current ratings to compressor nameplate.
| Item | Description |
|---|---|
| Start relay | Applies temporary current to the start winding to produce starting torque; might potentially be PTC, current-sensing or solid-state. |
| Overload protector | Opens the compressor common circuit under excessive current or temperature to protect the motor. |
| Terminal mapping | Wires to Common, Start and Run terminals; correct mapping is required for proper operation. |
Diagnosing common Failure Symptoms: electrical, Thermal, and Mechanical Indicators of Relay/Overload Fault
The 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit is a combined electrical protection and starting device that interfaces directly with the compressor’s three terminals (common, start, run).The relay portion provides the transient connection to the start winding so the compressor can overcome initial inertia, while the overload protector opens the circuit if the compressor draws excessive current or the internal temperature rises beyond safe limits. Functionally, a properly matched kit will show continuity patterns consistent with a healthy start circuit and will not exhibit sustained high current draw; compatibility requires the kit’s electrical ratings and terminal configuration to match the compressor’s nameplate specifications to avoid misoperation or nuisance trips.
Diagnosing failures relies on distinguishing electrical, thermal, and mechanical indicators: electrical issues often present as no-start or persistent humming with measurable abnormal current, thermal faults show open continuity at ambient once cooled or a hot-to-touch protector after repeated attempts, and mechanical failures manifest as rattling, seized rotor, or burnt terminals. Practical checks include measuring DC resistance between terminals and verifying line voltage appears at the start terminal only during the initial spin-up, monitoring inrush current with a clamp meter, and inspecting the kit for discoloration, melting, or loose connectors.Replace the kit only after confirming the compressor is not mechanically locked; if the compressor draws normal starting current and the kit still fails, verify part number compatibility and terminal layout before installing a replacement.
- electrical: humming,no crank,abnormal inrush or open/short on multimeter.
- Thermal: overheated or open overload after warm-up, protector trips repeatedly.
- Mechanical: rattling, seized shaft, burn marks at terminals.
| Item | Description |
|---|---|
| Electrical Indicator | Humming, high inrush current, or continuity faults between compressor terminals. |
| thermal Indicator | Overload opens after heat build-up; protector shows open at room temperature if failed. |
| Mechanical Indicator | Physical damage, loose terminals, seized compressor shaft preventing start. |
Compatibility, Replacement Considerations, Step‑by‑Step Installation and Troubleshooting Procedures for Service Technicians
The 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit replaces the start relay and thermal overload protector that manage compressor startup and short‑term overload protection on many Whirlpool family refrigerators. In operation the relay provides temporary current to the compressor’s start winding to produce the necessary torque to get the motor turning, and the overload opens the circuit when motor current exceeds its design limits or the motor overheats. Technicians will see specific failure behaviors: a clicking sound with no spin, a continuous hum without rotation, or an open circuit reading on the overload element. Check mechanical fit, terminal layout, and electrical ratings against the compressor’s stamped RLA/LRA and OEM cross‑reference to ensure compatibility rather than relying solely on physical size; mismatched overload trip points or improper terminal assignments can allow repeated failed starts or permit damaging overcurrents.
- Common symptoms indicating start kit replacement: repeated clicking, humming without start, tripped breaker on startup, or open/short readings on relay/overload.
- Basic troubleshooting sequence: disconnect power, document wiring orientation, measure continuity/resistance of start/run/overload terminals, replace only if readings are out of spec, then observe inrush and running current after reassembly.
Stepwise installation and technician checks: remove power and access the compressor; photograph and tag leads, then remove the old relay/overload and test it with a multimeter (overload should read continuity cold and open if blown; start relay frequently enough shows a low resistance between specific terminals or an open when failed). Fit the 4387535 kit in the same orientation, secure clips, and reconnect leads to their original terminals.After restoring power, verify the compressor starts within a couple of seconds, measure starting current with a clamp meter (compare to the compressor’s LRA/RLA), and confirm there are no abnormal noises, repeated starts, or high running current. If replacement does not restore operation, proceed to verify compressor winding resistances, check supply voltage and control board outputs, and inspect for mechanical seizure or refrigerant system lockups before repeating component changes.
| Item | Description |
|---|---|
| Replacement Part | 4387535 Whirlpool start relay and overload kit – matches start switching and overload protection functions |
| Fast Test | Multimeter continuity: overload = closed (cold), start relay = expected low resistance between start/run terminals; open indicates failure |
Q&A
What is the 4387535 Whirlpool Refrigerator compressor Relay and Overload Start Kit and what does it do?
The 4387535 start kit is an OEM replacement assembly that contains the compressor start relay (or start device) and the overload protector used on many Whirlpool-family single‑phase refrigeration compressors. The relay provides a short starting boost to get the compressor motor turning, and the overload protector stops current if the compressor overheats or draws excessive current, protecting the motor from damage.
How do I know if the start relay/overload (4387535) is the problem and not the compressor itself?
Common symptoms of a bad relay/overload include: compressor humming but not starting, fridge cooling poorly, clicking at the compressor, or intermittent starts. A quick check is to remove the relay and shake it (some relays rattle when failed) and inspect for burn marks.A multimeter can check for open/shorted windings on some relay types, but many modern relays are solid‑state and require swapping with a known good unit or using a service manual test procedure. If the compressor spins up with a known good relay or start kit, the relay was the problem.If it still won’t start, the compressor motor might potentially be locked or failed and needs professional diagnosis.
Is the 4387535 kit compatible with my Whirlpool/Kenmore refrigerator?
Compatibility depends on the refrigerator model and the specific compressor used. 4387535 is an OEM part used on many Whirlpool, Maytag, KitchenAid and Kenmore units, but you should confirm by checking the appliance model number and the part cross‑reference in Whirlpool’s parts list or on the label at the back of the fridge. Do not rely solely on visual similarity-always verify fit and terminal arrangement before installing.
Can I install the 4387535 start kit myself, and what safety steps should I take?
Yes, many appliance owners can replace the start kit themselves.Steps: unplug the refrigerator, pull it away from the wall, locate the compressor access panel (usually at the back bottom), remove the cover, disconnect the old relay/overload from the compressor terminals, and install the new unit in the same orientation.Safety tips: always disconnect mains power, avoid touching sharp sheet metal, note or photograph terminal wiring before removal to ensure correct reconnection, and don’t attempt internal compressor repairs. If you’re uncomfortable or the compressor area is hard to access, hire a technician.
How do I test the old relay/overload to confirm it’s faulty before replacing it?
Visual inspection can reveal burnt, melted, or discolored parts-signs of failure. for mechanical relays you can use a multimeter to check for continuity between appropriate terminals per the service manual. For PTC or solid‑state relays, bench testing is more limited; thay may appear open at room temperature but function under load. The most reliable home test is to temporarily replace the suspect relay with a known good one (or a new OEM 4387535) and observe whether the compressor starts normally. If uncertain, have a technician perform the electrical tests.
Will replacing the relay/overload prevent compressor damage or fix every start problem?
Replacing a failed relay/overload frequently enough cures start problems caused by those parts and can prevent further damage from repeated unsuccessful start attempts. Though, if the compressor windings are already damaged, the motor is seized, or there are other system issues (like a refrigerant restriction or electrical supply problem), replacing the relay will not fix the underlying issue. If the compressor still does not start after installing a new relay/overload, contact a qualified service technician for compressor diagnosis and repair.
Are there any differences between the 4387535 and aftermarket kits, and should I use OEM or aftermarket?
OEM 4387535 is manufactured to Whirlpool’s specifications and is guaranteed to match terminal layout, mounting, and thermal characteristics. Aftermarket kits vary in quality; some work fine and are less expensive, others may not match electrical ratings or physical fit. For reliability and to maintain warranty coverage, OEM parts are recommended-especially for critical components that protect the compressor.
How much does the 4387535 start kit cost and is it an economical repair?
the start kit is a relatively low‑cost part compared with compressor replacement. Prices vary by retailer and region but are typically inexpensive,so replacing the relay/overload is a cost‑effective first repair for a compressor that won’t start. If symptoms persist after replacement, factor in diagnostic labor and possible compressor replacement when evaluating total repair cost.
The Conclusion
The 4387535 Whirlpool Refrigerator Compressor Relay and overload Start Kit serves as a critical component in the refrigerator’s starting circuit, helping the compressor turn on reliably while protecting it from electrical overload and overheating. properly functioning relay and overload devices reduce the strain on the compressor during startup, contribute to consistent cooling performance, and can help prevent premature compressor failure by interrupting current in fault conditions.
As symptoms such as failure to start, intermittent running, or frequent humming can result from several possible causes, accurate diagnosis is essential before replacing components. Verifying the specific fault, confirming part compatibility, and following safe installation practices-or engaging a qualified technician-ensures the kit will restore reliable operation and avoid needless expense. Timely, correct replacement of a defective relay and overload is a cost-effective step to protect the compressor and maintain overall appliance 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
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Replacement parts for many appliance models can also be found at
Reliable-Parts-Hub
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