4387535 Whirlpool Refrigerator Compressor Relay Adn Overload Start Kit is âa replacement start-assist assembly that combines a compressor start relay with a thermal overload protector⣠used on⢠hermetic⣠refrigerator compressors. the kit comprises componentsâ that control the compressor’s start circuit-temporarily supplying additional starting current to the motor’s start winding (or⤠activating an internal start device) and protecting⤠the âmotor from sustained overcurrent or excessive temperature through a thermal cutout.
Inside the appliance, the relay and overload sit at the compressor terminal housing and form the interface between the appliance control system (thermostat or control board) and the compressor motor. The startâ relay⤠provides the short-duration electrical path or phase-shift needed to develop starting torque,⣠while the overload senses⣠motor temperature or current andâ opens the circuit to prevent winding damage; together they interact with⣠the âcompressor motor windings, the power supply, âŁany start capacitor or solid-state start deviceand upstreamâ controls. Although they do not interactâ directly with theâ refrigerant circuit, their correct operation is necessary for the compressor to run and maintain refrigeration performance.
In this article, readers will find a technical overview of howâ the â4387535 start kit functions, guidance on which⣠compressor and appliance models it is compatible with, common failure symptoms (for example continuous humming, no-start conditions,â tripped breakersorâ intermittent operation)and⤠step-by-stepâ troubleshooting diagnostics â¤such âŁas visualâ inspection, continuity and resistance checksand current measurements.The articleâ will also cover practical replacement considerations-matching electrical ratings and terminal âconfiguration, safe isolation and mounting proceduresand factors to verify in service manuals-so technicians, engineersand appliance owners can assess and address start-circuit issues methodically andâ safely.
Table of Contents
- Function âand Role of the Compressor Relay and Overload in⢠Whirlpool Refrigerators
- Howâ the 4387535 â¤whirlpool Refrigerator Compressor Relay And Overload Start â¤Kit Works Within the Compressor Circuit
- Common Failure Symptoms, Measured Electrical Faultsand Effects on Cooling Performance
- Compatibility, Replacement Considerationsand field Troubleshooting Procedures for the 4387535 Kit
- Q&A
- The Way Forward
function and Role of the Compressor Relay and overload in Whirlpool Refrigerators
The compressor relay and overload together provide the electrical start and short-term thermal protection functions that allow a sealed refrigerator compressor to spin up reliably. Theâ 4387535 Whirlpool⢠Refrigerator Compressor Relay âAnd Overload start Kit contains the start relay device that momentarily âconnects the compressor’s start winding and a thermal overload (a temperature-activated cutout) wired â˘in series âwith the âcompressor’s run circuit. The â¤relay type used on âŁWhirlpool unitsâ is typically either a current-sensing or PTC-style starter that closes for a fraction of a second to provide the extra torque âneeded during motor startup; âthe overload opens when the compressorâ draws excessive current or the internal case temperature rises, preventing winding⤠damage âŁfrom sustained locked-rotor â˘or overheat conditions.
- Common symptoms of a failing relay/overload: brief clicking without compressor run, humming âcompressor that does ânot reach full speed,⤠refrigerator temperature rise after⤠a âŁstart attemptor compressor that runs intermittently then stops.
| Item | Description |
|---|---|
| Startâ Relay | Briefly energizes the â¤start winding to achieve⤠startup torque; specified by coil behavior and contact timing. |
| Thermal Overload | Series protector that opens on âexcessive⢠current/heat to prevent winding damage; must be matched âto compressor thermal characteristics. |
For serviceâ and compatibility, âmatchâ the relay’s terminal arrangement and electrical characteristics (coil resistance, âtrip/currentâ thresholds) to the compressor’s âterminal cluster⣠and the model application; the kit is intended for directâ replacement on specified Whirlpool compressors but should be verified against model and serial number.Technicians verifying a failed relay/overload often bench-test â¤for continuity and resistance âŁacross the start and âŁrun terminals and observe whether the relay closes during⣠a powered â¤start;⣠never bypass the overload for testing-use proper test procedures or a known-good replacement. Correct installation⢠requires secure terminal connections and proper seating on the compressor body so the overload senses case temperature accurately; improper or mis-specified replacements can allow repeated hard â¤starts, overheatingorâ premature compressorâ failure.
How the⢠4387535 Whirlpool â˘Refrigerator Compressor Relay And Overload Start â˘Kit works Within the Compressor Circuit
the 4387535 Whirlpoolâ Refrigerator Compressor Relay And Overload Start Kit is a combined start relay and thermal overload protector that mounts on the compressor terminals and controls theâ compressor motorâ during âstartup⣠and fault conditions. In normal operation the start relayâ provides a brief connection to the compressor’s start winding to âŁproduce the torque needed⢠to accelerate the rotor;⣠onc the motor reaches near-run speed the relay disconnects the start winding and the â˘compressor continues on the run winding. The overloadâ protector is placed in series with the run⢠circuit and is a⣠temperature/current-sensitive device that opens the circuit during an overcurrent or âoverheating event, isolating the⢠motor toâ prevent damage until the device cools and resets.
In practice, this⢠kit interfaces with three-terminal hermeticâ motors â˘labeled C, Sand ⤠Rand must matchâ the âcompressor’s terminal layout âand electrical âcharacteristics to â˘operate correctly.Symptoms that typically âindicate âa failingâ relay/overload assembly include steadyâ humming with no start, frequent starter âŁclicks followed by no-run,â or a compressor that starts intermittentlyâ after a cool-down⢠period. Technicians should verify terminal continuity, measure resistance across windings, âand inspect for burnt âor deformed components before replacingâ the module. Typical behaviors and checks include:
- Momentary start engagement: relay closes only during crank-up, then opens at run speed.
- Thermal trip: overload opens under sustained high current/temperature⣠and resets after cooling.
- Compatibility check: ensure correct terminal arrangement and that relay ratings match compressor â˘locked-rotor and run currents.
| Item | Description |
|---|---|
| C, S, R | Compressor terminals: Common (C), Start (S), Run (R)⣠– verify wiring matches kit terminals. |
| Start relay | Supplies momentary power to the âŁstart winding; may be current- or voltage-sensing depending on design. |
| Overload protector | Series thermal/current protection that âopens under overcurrent or overheating and typically resets afterâ cooling. |
Common Failure⣠Symptoms, Measured Electrical Faultsand Effects on Cooling Performance
The 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start â¤Kit serves as the⢠interface that enables the compressor’s start winding to engage briefly and protect the motor fromâ prolonged overload. The kit typically contains a start relay or PTC device andâ an overload protector; together â˘they provide the timed â¤or temperature-dependent connection to the compressor’s start circuit and a thermal/open-circuit safeguard against excessive current. Technicians âshould â¤confirm terminal⢠style, mounting footprintand electrical ratings match the compressor before replacement â¤- physical âfit and the kit’s⣠intended compressor class âdetermine compatibility more than brand labeling alone.
Common measured electrical faults include an open overload (infinite resistance), aâ shorted⤠or grounded relay/connectoror abnormal resistance values between compressor terminals. Use a ⤠multimeter to verify continuity through the overload atâ room temperature, check that there is noâ continuity between compressor âwindings and chassis groundand compare resistance symmetryâ across the three motor⣠terminals; substantial deviation or â¤an open reading points to a failed start kit or a motor winding fault. Failed or marginal âstart components typically⢠present as a hard-starting or non-starting compressor (persistent hum, frequent thermal trips), sustained⢠high run-current with reduced coolingor intermittent cooling where the unit cools briefly then âwarms as the âŁoverload opens;â thes symptoms help prioritize inspection before âreplacing the compressor itself.
- Compressor hums but does not start (start relayâ or PTC failure)
- Thermal overload trips repeatedly (overloadâ open or motor drawing excess current)
- Long âŁrun â¤times with inadequate cooling (weak start engagement)
- Intermittent cooling cycles or partial cooling (degraded relay timing or intermittent connections)
- Visible âheat damage or melted terminals at the start kit (electrical fault)
| Item | Description |
|---|---|
| Overload continuity | Room-temperature continuity expected; open (infinite) reading indicates failed protector |
| Compressor â¤terminal resistance | low, finite ohms between windings (S-R,â R-C, S-C) andâ no âcontinuity to âchassis ground;â large asymmetry or open = fault |
| Relay/PTC condition | Mechanical âŁrelays show measurable coil resistance; PTC devices may⢠not behave like coils but must not be shorted⣠to ground or open-circuit at ambient |
Compatibility, Replacement Considerationsand Field Troubleshooting Procedures for the 4387535 Kit
The 4387535 Whirlpool Refrigerator Compressorâ Relay And Overload Start Kit is designed to provide â¤both a â˘starting relay function and aâ thermal overload protector for singleâphase household refrigeration compressors. In practice this kit replaces the mechanical or electronic start relay and the inlineâ thermal protector that interrupt the start winding⣠and protect the motor from overcurrent and overheating. Compatibility is determined by compressor terminal labeling (normally S, R, C or⤠equivalent), nominal supply voltage â(most domestic refrigerators use 115-120 Vâ singleâphase)and the physical mounting or clip arrangement; the â¤kit will not work with threeâphase compressors⤠or systems that require an external start capacitor. Technicians should âmatch terminal positions and verify that â¤the compressor type is aâ singleâphase hermetic motor before installing theâ replacement kit.
Field troubleshooting and âreplacement require both visual and âelectrical checksâ to isolate relay/overload failures from compressor or wiring⤠faults. Use âa multimeter to check continuity across â¤the âoverload⣠(should âopen when hot, closed at ambient) and to⣠measure the relay coil/element resistance accordingâ to the â˘manufacturer’s service data; a rapid click at powerâup with no compressor run current suggests a failed start device, whereas no click and no current draw can indicate an open line âŁor âblown overload.â For safe confirmation of a bad start component, verify line voltage at the compressor while observing inrush current âwithâ a â¤clamp ammeter during attempted start; if the⢠compressor âdraws high lockedârotor current but the relay never engages, replace âthe âstartâ kit. Follow the cabinet wiring diagram andâ ground the chassis before performing live testsand do not bypass⤠thermal protection accept for brief diagnostic checks âŁthat are promptly corrected.
- Quick checks: âverify correct terminal mapping (S/R/C), confirm 115-120 V supply, inspect for burned or â¤melted terminals indicating high âresistance.
- Common symptoms addressed: hard starting âŁor repeated clicking, compressor overheating and shutting downor â¤no run after start attempt.
- Diagnostic tools: multimeter (continuity/ohms),clamp ammeter for inrush,and a service manual for terminal identification âand expected resistance values.
| item | Description |
|---|---|
| Part | 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit – âstart relay + thermal overload |
| Typical Voltage | 115-120 Vâ singleâphaseâ household compressors |
| Compatibility | Singleâphase hermetic compressors âwith matching S/R/C terminals; not for threeâphase or capacitorâstart systems that require separate start capacitors |
| Field Test | Continuityâ across overload at ambient, relay engagement clickand inrush current measurement âduring â¤start |
Q&A
What is the 4387535 Whirlpool Refrigerator Compressorâ Relay and Overload⣠Start Kit and what â¤does it do?
The 4387535 is a compressor start â¤kit that includes a start relay and an overload protector. It helps the compressor motor start by â˘momentarily âconnecting the start winding and protects⢠the compressor from overheating or drawing excessive current. Replacing a âfailed kit can restore normal starting function when the âŁcompressor or else hums or refuses to run.
What symptoms indicate âŁthe start kit is failing or needs replacement?
Common symptoms include: compressor â˘humming â˘but not starting, clicking or tripping of the overload, refrigeratorâ notâ cooling, the compressor running intermittently or not at all,â and visible â˘burn marks âor a burnt smell ânear â˘the⤠relay. These signs point to start/overload problems but can also be caused by other faults, so diagnosis⤠is ârecommended.
How⢠can I confirm the 4387535 is compatible with my Whirlpool refrigerator?
Check your refrigerator⢠model number and consult the Whirlpool parts list or the appliance’s service manual. Many online parts retailers let youâ enter the model number âto confirm compatibility. Do not rely solely⣠on visual similarity-confirm the part number or model â¤fit list before purchase.
Can I replace the âŁ4387535⣠myselfand what safety precautions should I take?
Many homeowners with basic mechanical skills can replace the plug-in relay/overload on the compressor. Always disconnect power at the outlet or breaker before working on the fridge. Avoid touching compressor terminals with âŁthe fridge energized. If you are not agreeable working near the compressor or removing panels, hire a qualified technician.
How do I test âŁthe relay and overload to determine if they’re faulty?
Start with âa⢠visual inspection: look for burn⣠marks, melted plasticor a strong â¤burnt odor.⤠with power disconnected, you can test continuity through the overload protector with a multimeter-an open circuit typically indicates failure.Some relays (PTC/electronic types) are harder to bench-test; technicians may swap with a known-good relay or measure current draw/voltage âat the compressor during start attempts. When in doubt, replace the â¤kit or consult a technician.
If theâ compressor hums but won’t start, willâ replacing this start kit fix âthe âproblem?
Frequently â¤enough yes-if the issue is a failed start relay or overload, replacing the kit commonly restores âstarting and cooling. Though,similar symptoms can âŁcome from a seized compressor,a failed start winding⣠inside the âcompressor,a bad⢠capacitor (in some designs),or⤠a ârefrigerant/sealed-system fault. If replacing the kit doesn’t help, further diagnosis by a technician is needed.
Is 4387535 anâ OEM part and what is the typical cost?
The 4387535 is an official Whirlpool service part used â˘on a range of their refrigerators. Prices vary by retailer and region, but it is indeed generally âŁan inexpensive âŁpart compared with major components-typically in theâ tens of dollars.Purchasing from authorized dealers or Whirlpool parts suppliers ensures you get a genuine part and any applicable warranty.
Any installation⤠tips âor post-replacement troubleshooting I should know about?
Beforeâ reassembly, ensure the relay/overload is firmly seated on the âŁcompressor terminals and wiring is secure. Restore power and listen⤠for the compressor starting; allow several minutes for the sealedâ system to stabilize. If the compressor still fails âto start, check compressor current draw and electrical supply voltageand â˘inspect the evaporator fan and defrost system for âother causes of no-cooling. If you suspectâ internal compressor failure or a sealed-system âŁissue, contact a certified appliance technician.
The Way Forward
The 4387535 Whirlpool refrigerator Compressor Relay and âOverload âŁStart Kit âplays aâ focused but critical role in refrigerator operation â¤by⣠helping the compressor start reliably and protecting it from electrical overload and overheating. When functioning properly,â the⢠relay and overloadâ assembly contributes to⣠efficient compressor cycling, reduces strain on the motor during startup, â˘and helps prevent premature compressor failure⢠that can âled to costly âŁrepairs or food loss.
Accurate diagnosis â¤and timely âreplacement of⣠a failing 4387535 kit are significant âto restore normal operation and âŁto avoid âsecondary damage to âthe compressor and other refrigeration components. Symptoms such as repeated clicking,â a compressor that âŁdoes not start, unusually long run timesor evidence of overheating warrant testing of the start device â¤and related circuits. Proper testing, selection of the correct replacement partand correct installation help ensure safe, reliable performance and are typically more cost-effective than deferring repair until more extensive âfailure occurs.
Maintaining a methodical approach-documenting symptoms, performing⤠appropriate electrical and mechanical checks,⣠and following manufacturer specifications for replacement-supports long-term â¤applianceâ reliability and⤠safety. When in doubt, consulting a qualified technician⤠for diagnosis and replacement of the 4387535 Whirlpool Refrigerator Compressor âŁRelay And Overload Start Kit is a prudent step to âŁconfirm the issue and to ensure the work⣠is completed correctly.
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