4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit is a compressor start device assembly that combines a start relay and an overload protector intended for use with single‑phase hermetic refrigerator compressors. It is indeed a control and protection component-typically an electromechanical or solid‑state relay paired with a thermal or electromechanical overload-that mounts at or near the compressor terminals and provides the transient connection to the start winding while guarding the motor against sustained overcurrent or overheating conditions.
Inside the appliance, the kit interfaces directly with the compressor motor windings, the refrigerator thermostat or control board, and the supply mains.During a start attempt the relay supplies the start winding (or shifts the circuit configuration) to generate the additional torque required to spin a stalled rotor; once the compressor reaches operating speed the relay opens or reduces current to the start circuit.The overload portion is a temperature/current‑sensing device that opens the motor circuit when thermal or overcurrent thresholds are exceeded, preventing winding damage and helping to avoid repeated unsuccessful starts that can stress the refrigeration system.
In this article readers will find a technical clarification of how the 4387535 kit functions, guidance on model and compressor compatibility and electrical characteristics to check before replacement, a list of common failure symptoms to recognize (for example repeated clicking, compressor hum without start, or tripped overloads), step‑by‑step troubleshooting methods including continuity, resistance and amp draw checks, and practical replacement considerations such as matching terminal layout, thermal ratings, and safe disconnection procedures. The intent is to provide technicians, engineers, and informed appliance owners with the diagnostic context and decision criteria needed to evaluate, test, and, when appropriate, replace this start relay and overload assembly.
Table of Contents
- Function and Role of the Compressor Relay and Overload Start Kit in the Refrigeration Cycle
- How the 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit Works Inside the Appliance
- Common Failure Symptoms and Diagnostic Indicators of Relay and Overload Start Kit Malfunctions
- Compatibility, Model Interchangeability, Replacement Considerations, and Installation Procedures
- Q&A
- In Conclusion
Function and Role of the Compressor Relay and Overload Start Kit in the Refrigeration Cycle
The 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit combines a start relay, which engages the compressor’s start winding for the brief interval required to bring the motor up to speed, with an overload protector that interrupts power if the motor draws excessive current or overheats. During a normal refrigeration cycle the thermostat closes and applies line voltage to the compressor; the relay provides a low-impedance path to the start coil so the compressor develops sufficient starting torque, then drops out once the motor reaches running speed. The overload is a thermal or current-sensitive device wired in series with the compressor’s common terminal to open the circuit in overcurrent or overheating conditions, preventing winding damage and possible burn-out.
Technically, compatibility depends on terminal layout, coil impedance, and rated voltage-most applications for this kit expect three-terminal compressors (Common, Start, Run) and standard household supply (typically 115-120 V in North America), but confirm with the compressor nameplate and wiring diagram before replacement. Practical diagnostics: a failed relay frequently enough produces continuous humming without starting, or clicking as the relay attempts to engage; an open overload results in a loss of power to the compressor and can show as a dead motor with no clicking. Technicians commonly verify component function by measuring coil resistance,performing a bench swap with a known-good relay,or observing inrush current with a clamp metre to determine whether the start circuit is engaging properly.
- Common failure symptoms: humming/no start, frequent start/stop cycles, warm compartment, or no compressor activity with power applied.
- Installation checks: match terminal labels, confirm voltage, and ensure secure spade connections and correct orientation to avoid miswiring the start/run circuit.
- Field test tips: measure start coil resistance and monitor inrush current to distinguish relay failure from a seized compressor.
| Item | Description |
|---|---|
| Function | Start relay provides momentary engagement of the start winding; overload opens the circuit under overcurrent/thermal stress. |
| Typical ratings | designed for standard refrigeration compressors at household line voltage; check nameplate for exact amp/voltage compatibility. |
| Fitment | Intended as a replacement kit for compatible Whirlpool compressors-verify model/terminal layout before installation. |
How the 4387535 Whirlpool Refrigerator Compressor relay And Overload Start Kit Works Inside the Appliance
The 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit is a combined electrical starter assembly that controls the compressor’s initial inrush current and protects the motor from thermal or current-induced damage. The relay provides a brief connection to the compressor start winding or engages an internal start assist device so the rotor achieves sufficient torque to begin rotation; once the compressor reaches running speed the relay opens and the motor operates on the run winding. The overload protector is a temperature- and current-sensitive switch mounted in series with the compressor that opens if the winding temperature or sustained current exceeds safe limits,preventing damage from locked-rotor conditions,stuck valves,or refrigerant undercharge. In typical Whirlpool installations this kit is clipped directly to the compressor terminals and must match the compressor terminal layout and electrical ratings for reliable operation.
- Typical symptoms of relay/overload failure: rapid clicking,compressor humming without start,or intermittent starting that clears after cooling.
- Behavior under fault: relay may stick closed (continuous start winding) or fail open (no start), while overload trips open under overcurrent and will only reset after cooling.
- Compatibility considerations: verify terminal configuration (S, R, C), voltage rating, and mounting style to ensure direct replacement.
From a practical servicing perspective, the start kit functions as the interface between household supply and the compressor motor during the high-stress start interval; technicians confirm kit operation by measuring voltage at compressor terminals during a start attempt and by checking for continuity of the overload at ambient temperatures. The assembly does not change compressor refrigeration characteristics-its role is strictly electrical-so mismatched kits can produce proper cooling but shortened motor life or immediate starting problems. When replacing the part, compare electrical ratings and terminal arrangement rather than only part number to ensure functional compatibility across different Whirlpool compressor models.
| Item | Description |
|---|---|
| Start Relay | Provides momentary connection to the start winding to achieve motor torque at startup. |
| Overload Protector | Opens the circuit under sustained high current or elevated winding temperature to prevent motor damage. |
Common Failure Symptoms and Diagnostic Indicators of Relay and overload Start Kit Malfunctions
The 4387535 Whirlpool Refrigerator Compressor Relay And Overload start Kit combines a start relay (or PTC/switch mechanism) with an overload protector to engage the compressor’s start winding and protect the motor from sustained overcurrent or overheating. In normal operation the start relay provides a brief high-torque impulse to the start winding so the compressor accelerates to running speed, while the overload opens under excessive current or thermal stress to prevent motor damage. Failures typically manifest as electrical or mechanical symptoms rather than gradual refrigerant changes, and compatibility with the compressor’s design and nominal line voltage is critical-substituting a non‑OEM start component can result in weak cranking, extended start attempts, or nuisance overload trips that mimic refrigerant or compressor mechanical faults. Such as, a refrigerator that attempts to start for several seconds and then clicks off repeatedly usually indicates the relay cannot provide the initial start boost or the overload is opening under excessive inrush current.
- Repeated clicking with no compressor run: relay is failing to close or has internal PTC degradation.
- Sustained humming of the compressor motor without spin-up: start winding not being switched in, or relay contacts welded/shorted.
- Compressor starts then rapidly trips off (warm compressor casing): overload opening due to overheating or high current draw.
- Intermittent starting or only starts after manual tapping: degraded relay contacts or intermittent internal connection in the kit.
- visible discoloration, melted housing, or burnt terminals: thermal failure of the overload or poor terminal connection.
Technicians confirm a relay/overload kit fault with targeted electrical checks: measure supply voltage at the compressor terminals under start attempt, observe the presence or absence of a start‑spike current with a clamp meter, and verify continuity through the overload at ambient temperature.Disconnect power before performing continuity checks; the overload protector should be closed at room temperature and open only under elevated temperature or fault conditions. When measurements are inconclusive, a controlled substitution with a known-good OEM 4387535 unit or inspection against service manual wiring diagrams provides definitive confirmation-using a mismatched relay can reduce starting torque or allow prolonged inrush that trips protective devices. For practical troubleshooting, combine visual inspection, static continuity tests, and dynamic current/voltage observation during a start attempt to distinguish relay/overload faults from compressor mechanical failure or low refrigerant conditions.
| Item | Description |
|---|---|
| Start behavior | Clicking or humming without spin-up indicates start circuit or relay failure |
Compatibility, Model Interchangeability, Replacement Considerations, and Installation Procedures
The 4387535 Whirlpool Refrigerator Compressor relay And Overload Start Kit combines a start relay and thermal overload protector to provide the momentary high-torque starting current to the compressor’s start winding and to disconnect the compressor on sustained overcurrent or overheating. The relay closes the start winding circuit for a fraction of a second during startup, and the overload opens the run circuit if the compressor draws excessive current or runs hot; together they prevent repeated hard starts and protect the sealed motor. Compatibility depends on physical terminal layout (typically the three compressor terminals S-R-C), the compressor’s rated line voltage and locked-rotor current, and the mounting/clip arrangement; a kit that matches those electrical and mechanical parameters will perform like the original, while units with different terminal arrangements or electronic start systems are not interchangeable.
- Disconnect power,remove compressor access panel,and label wires before removing the old relay/overload.
- Verify terminal layout and compressor nameplate ratings (voltage and locked-rotor amps) against the replacement kit.
- Install the new relay/overload by seating it on the compressor terminals and securing any retaining clip, then restore power and observe startup behavior.
When replacing the relay/overload, inspect the compressor terminals and harness for heat damage and measure coil resistance and continuity with a multimeter to verify motor and relay states; persistent humming or failure to start after installing a correct kit indicates a locked rotor, internal motor fault, or sealed-system problem rather than a start-component failure. Technicians should replace both the relay and overload together from the same kit to ensure matched activation timing and thermal characteristics, and they should confirm that the replacement matches the compressor’s electrical spec sheet; replacing a mechanical relay kit on a refrigerator that uses an electronic start device will not correct starting faults and can lead to repeated failures or diagnostic confusion.
| Item | Description |
|---|---|
| Terminal configuration | Typically 3 terminals (S, R, C) – confirm layout matches compressor base |
| rated supply | Usually 115 V AC for household models; verify nameplate voltage |
| Function | Relay provides start boost; overload protects against sustained overcurrent/overtemperature |
Q&A
What is the 4387535 Whirlpool Refrigerator Compressor Relay and Overload Start Kit and what does it do?
The 4387535 kit is a replacement start device assembly for manny Whirlpool-family refrigerators. It typically contains a start relay (or PTC start device) and an overload (thermal protector) that mount on the compressor terminals. The start relay gives the compressor motor the initial push to start, and the overload protects the compressor from excessive current/heat. Together they allow the compressor to start and protect it during operation.
How do I know if the relay/overload (4387535) is bad and needs replacing?
Common symptoms include a refrigerator that is warm, the compressor humming or clicking repeatedly but not running, intermittent cooling, or the compressor starting only after multiple attempts. Visual signs of failure can include burn marks, melted plastic, or corrosion on the unit. Though these symptoms can also be caused by a seized compressor or problems in the sealed system, so confirm by testing before replacing the part.
Can I test the 4387535 relay/overload at home and how?
Yes – but always disconnect power first.Remove the part from the compressor terminals and inspect visually. Use a multimeter on continuity/ohms: the overload should show continuity if cold (it’s a thermal protector). The start relay may show some resistance or change in continuity depending on type; an open circuit usually indicates failure. Another practical test: with power off, swap in a known-good start kit or temporarily push the compressor to start (careful, only if you know what you’re doing); if the compressor then runs, the relay/overload was likely bad. If you’re unsure, have a technician confirm (compressor motor tests and amp draw measurements can better isolate the problem).
Is replacing the 4387535 kit something I can do myself? What precautions and tools are needed?
Replacing the kit is a common DIY repair and usually straightforward: unplug the refrigerator, pull it away from the wall, locate the relay and overload on the compressor, remove the mounting clip or screws, disconnect the terminals, and install the new kit. Basic tools: screwdriver, needle-nose pliers, and possibly a socket set. Safety precautions: always disconnect power before working, avoid bending or stressing refrigerant lines, and keep fingers clear of sharp sheet metal. If the compressor is seized or the sealed system is damaged, do not attempt further sealed-system work-call a certified technician.
Will replacing the relay/overload fix all compressor start problems?
not always. if the start relay or overload is faulty, replacing the kit frequently enough restores normal starting. But if the compressor itself is mechanically locked/seized, the start device won’t cure the problem and the compressor may draw excessive current or be damaged. Also, problems with the fridge’s control board, wiring, or the sealed refrigerant system will not be fixed by a relay change. if replacement does not restore operation, further diagnosis by a technician is recommended.
Is 4387535 a direct OEM replacement for my Whirlpool/Maytag/Kenmore model?
4387535 is an OEM Whirlpool start relay/overload used across many Whirlpool, Maytag and Kenmore models, but compatibility varies.Always confirm fit by checking your refrigerator model number and cross-referencing with the part number on the manufacturer’s parts diagram or a reputable parts supplier. Do not rely solely on physical similarity-terminal layout and mounting style must match.
Can I use an aftermarket or universal start kit instead of the Whirlpool 4387535?
Aftermarket or universal kits are available and can work,but quality varies. A proper replacement should match the electrical ratings, terminal arrangement, and mounting method of the original. Using a mismatch can cause poor starting performance or damage.When possible use the OEM 4387535 or a verified equivalent that lists your appliance model in its compatibility list.
Does replacing the 4387535 require handling refrigerant or opening the sealed system?
No.Replacing the start relay and overload is an external service that connects to the compressor terminals only and does not require opening the sealed refrigerant system or handling refrigerant. If the problem is in the sealed system (loss of refrigerant, valve failure, or internal compressor failure), that will require a certified HVAC/R technician to service the sealed system.
to sum up
The 4387535 Whirlpool Refrigerator Compressor Relay and Overload Start Kit serves a critical role in initiating and protecting the compressor motor.By providing the necessary start assistance and thermal/electrical overload protection, the kit helps ensure reliable compressor starts, stable refrigeration performance, and reduced risk of motor damage. Properly functioning start components contribute to consistent temperature control, efficient operation, and avoidance of more extensive mechanical failure.
as symptoms of start-component failure can resemble other refrigeration issues, accurate diagnosis is essential before replacing parts. When testing confirms the 4387535 relay and overload as the cause, timely replacement with the correct kit helps restore reliable operation and can prevent costly compressor failure. For best results and safety, follow manufacturer guidance or engage a qualified technician and use the appropriate OEM replacement to maintain performance and longevity.
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