4387535 Whirlpool âŁRefrigeratorâ compressor Relay â˘Adnâ Overload Start⢠kit â˘is a combined startâ device âand thermal protector designed for⤠singleâphase refrigerator compressors. The âŁkit âtypically consists of a start relay (wich momentarily⢠connects the compressor’s start winding âŁor alters start⤠circuit impedance⣠to provideâ initial torque) and an overload âprotectorâ (a thermal or currentâsensing device that âopens the compressor supplyâ when operating temperature or current exceeds safeâ limits).⣠As a discrete service part it replaces factory original relay/overload assemblies âmounted on or near the hermetic compressor housing.
Inside the appliance the relay and overload âbehave as anâ interfaceâ between the refrigerator’s control system and the compressor motor. â˘During a âstart â¤sequence the relay provides â¤the â˘transient electrical⤠condition â¤necessary for the compressor’s motor to overcome static friction and reachâ running speed;⢠the overload sits inâ series with⤠the compressor supply to interrupt âpower â¤if the motor draws excessive⢠current⢠or overheats. Theâ assembly therefore interacts directly with⢠the âŁcompressor’s start and â˘run windings, the incoming mains and â˘cabinet controls (thermostat or control board), â¤and⤠indirectly affects refrigerant circulation, evaporator defrost cycles âand overall system pressures through its influence on compressor operation.
Inâ this article readers will find a technical explanation of â¤how the 4387535 kit functions, guidance on âverifying compatibility with âspecific compressor modelsâ and electrical ratings, common failure symptoms to recognize (such as humming with no start, intermittent starts, rapidâ cycling or excessive starting current), practical⣠troubleshooting stepsâ using basic diagnostic âtoolsand â˘replacement considerations such asâ matching terminal configuration, current and temperature âŁratings, mounting method and â˘safety precautions. The coverage is intended toâ help technicians, engineers andâ appliance owners âmake⤠informed decisions about diagnosis, âpart selection and safe replacement⢠practices withoutâ prescribing specific marketing choices⣠or exaggerated performance claims.
Table of contents
- Function andâ Role â¤of the Compressor Relay and Overload Start Kitâ in the Refrigerator Refrigeration Cycle
- How the 4387535 Whirlpool Refrigerator âCompressor Relay⤠And Overload⢠Start Kit Operates Within the Compressor Motor Circuit
- Common Failure âSymptoms and Electrical/Mechanical Diagnostic Indicators for Relay and Overload Assemblies
- compatibility,Replacementâ Considerations,Installation Procedures â¤and⣠Troubleshooting Workflow
- Q&A
- The Way Forward
Function and Role of the Compressor âRelay and overload Start âKit âin the Refrigerator Refrigeration Cycle
The 4387535 Whirlpool Refrigerator Compressor Relay And Overload Start Kit combines the momentary starting relay and theâ thermal overload â¤protector that â˘together manage compressor startup âand protect âŁthe âmotor during âŁthe refrigeration cycle. The relay provides a âtemporary high-torque current path âto the compressor’s start⣠winding â¤(or engages anâ external⢠start device) only while the âmotor accelerates; once the ârotor âŁreaches operating speedâ the relay opens⤠or disengages,⣠leaving the run âwinding⢠to maintain compressor operation. The overload is a â¤temperature-â or current-sensitive normally-closed protector mounted on âtheâ compressor shell that â¤opens the circuit under sustained âovercurrent or excessive temperature, preventing winding damage and internally-locked-rotor failures. In âpractical⢠installationsâ the kit mounts on the â¤compressor terminal block and must match the compressor terminal layout âand voltage rating to⣠function correctly.
Behavioral and compatibility aspects⤠dictate â˘both âŁdiagnosis⤠and replacement practice:⣠a failed â˘relay often produces rapid⢠clicking,a persistent humming compressor that does not⤠start,or repeated attempts to start âfollowed âby overload trips; a failed overload âŁwillâ interrupt run current and leave theâ system non-operational⣠until âŁit cools or is replaced. Typical technician checks include measuring line voltage at compressor terminals,verifying continuity across ârelay contacts during manual⤠stimulation,and comparing terminal⣠orientation â¤to the replacement kit. Symptoms, installation notesand quickâ reference values are summarized below to aid âtroubleshooting and part selection.
- Common symptoms: ârepeated clicking, compressor hum without rotation,â fridge warm while fan runs.
- Diagnostic â¤checks: lineâ voltage, continuity across overload,â audibleâ relay actuation during startup.
- Installation â˘tips: match terminal patternâ and voltage rating, ensure firm terminal connections, mount âŁkit to compressor âshell for accurate âŁthermal âresponse.
| Item | Description |
|---|---|
| Function | Relay provides startup⢠current; â¤overload protects against sustainedâ overcurrent/overtemperature. |
| Typical location | Mounted on compressor terminal block/shell in close physical⣠contact âwith compressor body. |
| Compatibility notes | Must match âcompressor terminal âconfiguration and operatingâ voltage; verify OEM part cross-reference before replacing. |
How the 4387535 Whirlpool Refrigerator Compressor Relay And Overloadâ Start Kit operates Within â˘the Compressor Motor Circuit
The 4387535⣠Whirlpool Refrigerator Compressor â˘Relay And âOverload Start Kit combines a startâ relay andâ a thermal overload into a singleâ replacement assembly⢠that controls âhow the compressor âmotor energizes and is⣠protected. In operation, the relay provides aâ timedâ or current-sensitive connection to the compressor’s âŁstart âŁwinding to produce the initial torque needed to turn the âŁmotor, then removes that connection once the motor reaches running speed.â The⢠thermal overload â¤is wired in seriesâ with âthe compressor supply (typically the common led)⤠and⤠interrupts power if the compressor draws excessive current or the âmotor temperature rises beyond⣠safe limits.â This⤠kit is intended for useâ on âthree-terminal hermetic compressor motors where a discrete start device â˘and an overload protector areâ required for safe, reliable⤠starting and â¤protection âduring⣠stall âor overcurrent conditions.
During a⣠normal âstart cycle the relay âŁallows âaâ higher current or aâ start-phase⢠path âforâ a brief interval; once âŁthe run speed âand backâ EMF reduce â¤the needâ for⤠start winding current, the⤠relay opens â˘(or drops out) and the compressor continues on the⣠runâ winding only. The overload remains⢠closedâ while temperature and current⢠are within limits and will open to de-energize the compressor if a stuck rotor,â locked loador âsustained overheating âoccurs, âpreventing further âdamage. Techniciansâ typically check âfor relay failure âby observing symptoms âsuch as â¤repeated⣠clicking,⤠a humming âcompressor that â˘will ânot â¤startor an overload that has tripped; bench tests includeâ continuity and resistance checks across the three compressor terminals and verifying â¤that the relay disengages after the motor comes up to â¤speed. Practical replacement considerations include matching terminal layout and physical mountingâ to ensure correct electrical sequence and adequate thermal contact forâ the overload âelement.
- Primary behaviors: provides momentary start energization; overload â˘opens on⣠overcurrent/overtemperature.
- Compatibility: designed for three-terminal hermetic compressors; ensure terminal mapping⣠matches the compressor block.
- Common failure symptoms: non-starting compressor with hum, rapid cycling, âor a visibly tripped overload.
| item | description |
|---|---|
| Relay function | Connects start â˘winding during âinitialâ spin-up, thenâ disconnects once running speedâ is reached. |
| Overload function | Series thermal/current protector that opens to disconnect compressorâ on sustained⢠overload or overtemperature. |
| Typical â˘terminals | Common (C), Start (S), Run (R) – â¤match to compressor terminal â˘block. |
| Failure indicators | clicking relay, â¤humming/no-start compressor, â˘or repeated trips of the overload |
Common Failure Symptoms and Electrical/Mechanical â¤Diagnostic Indicators forâ Relay and Overload Assemblies
The relay⢠and overload assembly controls the compressor’s start sequence âand â˘protects the motor⤠from overcurrent â¤and overheating. The â 4387535 âWhirlpool Refrigerator Compressorâ Relay And Overload Start Kit replaces the start relay⢠(or PTC/current-sensing element) and the thermal overload used on⤠manyâ singleâphase hermetic compressor motors; a failingâ relay⤠or⣠overload typicallyâ produces audible and electrical symptoms rather⣠than visible refrigerant-related faults. Common âfield â¤symptoms âinclude a hard-starting compressor that â˘hums but does not run,immediate tripping of the overload after âa brief run,intermittent starting,or a compressor that will runâ only when lightly tapped.⢠Compatibility considerationsâ include terminal layout, mounting type,â and nominal voltage/current ratings-using âa physically similar part with âincorrect âŁratings can allow initial operation but cause premature failure or inadequate⣠protection.
Diagnosing relay versusâ overload faults requires both visual inspection and electrical measurements: the overload is normally a closed device âŁthat opens âunder excessive temperature or current, so an open circuit at âambient temperature indicates a failed protector; the startâ relay (PTC or current relay) may show highâ resistance, a short to âŁgroundor loss âof the lowâimpedance start path. Practical diagnostic steps include measuring continuity between âcommon and âstart terminals with the âcompressor⢠disconnected, checking resistance values⢠against OEMâ specificationsand âobserving compressor behavior when a known-good start device isâ temporarily substituted⣠(performed only by qualified technicians with proper safety precautions). Mechanical indicators⣠such âas melted plastic, burned⤠contactsor a distorted housing frequently⣠correlate with internal thermal or overcurrentâ events⢠and should â˘prompt replacement ârather âŁthan repair.
- Compressor hums but âdoes not start – likely⢠open/failed start device or weak start winding.
- Compressor starts then trips after short run – overload opening due⤠to overcurrentâ or high ârunning âtemperature.
- Intermittent starting/cycling⣠– marginal relay/PTC performance or intermittentâ thermal âcontact.
- Visible damage â(charring,â melted housing) – â¤replace instantly; often indicates thermal â¤runaway or short.
| Item | Description |
|---|---|
| Humming/no-start | Start relay failed to provide inrush path; bench⣠testâ or â˘substitute start device⣠confirms relay fault. |
| Immediate trip after start | Overload âopens due âŁto excessive âcurrent or internal overheating; measure continuity cold and⢠inspect compressor load. |
| Intermittent operation | Intermittent contact orâ marginal PTC characteristic; evaluate resistanceâ stability and perform run/load observations. |
Compatibility, Replacement Considerations, Installation Procedures and Troubleshooting âWorkflow
The⢠4387535 Whirlpool Refrigerator âŁCompressor Relay And Overload Start Kit combinesâ a start relay âand âthermal overload protector âŁthat work together to establish the starting current path for the compressor and⤠to remove power if âŁthe motor overheats or âdraws an excessive current. Functionally, the relay momentarily connects the start winding to the supply to generate the necessary starting torque, while the overload⤠opens under sustained overcurrent or high temperature â¤to protect the compressor. Compatibility â¤depends â˘on the compressor’s⤠electrical characteristics⣠(ratedâ voltage, âŁstart and run winding resistanceand terminal arrangement) and the kit’s physical mounting and terminal configuration; technicians should confirm â¤the refrigerator model,â compressor nameplate ratingsand the relay’s terminal layout before installing theâ kit. Check whether the⣠original usedâ a â¤PTC-type or mechanical relay and ensure the replacement matches the compressor’s voltage âand terminalâ designâ to avoid misoperation â¤or âmechanical stress on terminals and⣠harnesses.
- Disconnect power and document âterminal positions/photograph connections âbefore removal.
- Symptoms indicating relay/overload failure: repeated clicking,⤠compressor hum without start, â˘warm compressoror visible charringâ on the relay body.
- Quick bench checks: continuity across overload, proper continuity/transition â˘of ârelay terminals when energizedand comparison of start âwinding â˘resistance⢠to nameplate⢠or service data.
| Item | Description |
|---|---|
| part | 4387535⢠Whirlpool â¤Refrigerator Compressor Relay⤠And Overload Startâ Kit |
| Compatibility | Designed for common single-phase ârefrigerators; verify âcompressor nameplate âvoltage and terminal orientation prior âto replacement |
| Technical reference | Rated⣠for typical household 120 VAC systems; consult compressorâ nameplateâ forâ start/run âŁwinding resistance and current limits |
Installation⣠and troubleshooting follow a structured workflow: isolate⢠mains, remove the âaccess panel, inspect the old relay/overload for â˘thermal damage or carbon tracking,â and replace using the same terminal sequence andâ mounting orientation âto preserve stress relief on the wiring. After replacement,measureâ supply voltage at the compressor,verify continuity across theâ overload with the⣠unit⢠de-energized,then restore power andâ observe starting behaviorâ while⢠measuring inrush current with a âclamp meter if available; a correct âŁinstallation will result in a brief high inrush current during startup followedâ by ânormal running current.⢠If âŁthe new kit âdoes â˘not correct the fault, proceed to verify compressor windings for shortâ or open circuits, check the start capacitorâ (ifâ present) and control boardsand consider sealed-system â˘faults-document findings andâ escalate to sealed-system service if compressor windings test within specification but the unit still fails to â˘start.
Q&A
What is the 4387535â Whirlpool Refrigerator Compressor Relay âand Overload Start Kit?
The â˘4387535 kit isâ a âŁreplacementâ start âŁkit for certain whirlpool-brand â¤refrigerators âthat contains the compressor â˘start relay and the thermal â˘overload protector. The relay gives the compressor an extra starting boost⤠and the overload⤠protects the compressor motor from âoverheating âor drawing â¤excessive âŁcurrent. Together they help theâ hermetic compressor start reliably⣠and âprotect it⢠from damage.
What common symptoms indicate the â˘relay/overload kit â¤needs replacing?
Common symptoms include: the refrigerator ânot â˘cooling⤠while â˘the compressor either does notâ run or only hums, a loud humming or clicking noise from the compressor area, the âcompressor starting intermittently or only after longâ delays, â¤frequent tripping of the â¤circuit â¤breakeror a âŁburnt electrical â˘smell near âthe relay. If the compressorâ won’t start but gets warmorâ the unit repeatedly starts and stops, the⤠relay or overload is aâ likely culprit.
How can I test the relay and overload before replacing⤠them?
Always disconnect power⣠first. Removeâ the relay/overload⢠from⤠the compressor and test with a âŁmultimeter.⤠The overload (a thermal protector)⤠should show electrical continuity at room temperature; âŁanâ open âcircuit indicates failure. For âthe ârelay, â¤check for continuity between the appropriate terminals⢠per the part diagram – many relaysâ will show low resistance âŁacross start/run terminals or continuity through the âŁstart⣠circuit. â˘Also listen for a â¤clicking â¤sound during attempted âstart (relay engaging). If you’re unsure interpreting results, consultâ a âqualified appliance technician. Do âŁnot attempt âhigh-voltage bench testing unless trained.
Can I install âthe â4387535 kit myself, âor do âI need a technician?
If you⢠are⢠comfortable working safely with appliances and âbasic hand tools, you canâ replace the plug-in⣠relay/overload yourself: unplug the refrigerator, access the âcompressor (usually at the back behind a lower access panel), remove the old relay/overload âfrom the compressor terminals andâ install the new unit, then restore power⢠and verify⢠operation. However, if the â¤compressor ârequires refrigerantâ work or the compressor itself is suspected to be failing, you should hire a licensed appliance or ârefrigeration â¤technician. Always disconnect power before servicing.
Is the 4387535 kit compatible with all Whirlpool refrigerators?
No-this kit is â¤compatible only with⣠refrigerators that â˘use a conventional hermetic compressor with a plug-on relay/overload âŁassembly. It is indeed not compatible with inverter or variable-speedâ compressors used in some modernâ models. Always check your⣠refrigerator’s modelâ number and the parts diagram (or the OEM cross-reference) to confirm compatibility before purchasing.
Will â¤replacing the relay/overload fix a compressor thatâ willâ not start at all?
Sometimes yes: if the compressor is otherwise healthy but the⢠start relay orâ overload⤠has âŁfailed, replacing âŁthem will restore starting⢠function.However, ifâ the compressor has an internal mechanical failureâ (locked â˘rotor, burned windings, loss ofâ refrigerantor internal short), replacing the relay/overloadâ will not fix⢠it. If the compressor âŁstill won’t run after installing a âknown-good relay/overload, the compressor âlikely⣠needs professional diagnosis or replacement.
What safety precautions should⣠I take when â˘replacing the relay/overload?
Unplug the refrigerator before doing any work. Work onâ a cool, dry surface withâ the appliance disconnected from mains power. Avoid shorting compressor terminals together.⣠Do not attempt refrigerant- or compressor-specific âŁrepairs unless you are certified⢠(refrigerant handling laws apply in many places). If you smell burning or see oil on the compressor shell, stop and consult⤠aâ technician-these can indicate more serious âŁcompressor damage.
Should I buy an OEM 4387535 â¤kit or â¤is an aftermarket version acceptable?
An OEMâ (Whirlpool-branded) part guarantees fit â¤and the âŁcorrect electrical â¤characteristics for the intended âŁmodels. Many reputable aftermarket âkits also work fine âand can be less expensive,⤠but quality and specifications vary. Buy from a trusted supplier,compare part numbers and connector types,and verify â˘model compatibility. If unsure, using â˘the OEM part eliminates uncertaintyâ about â˘fit âand function.
The Way Forward
Theâ 4387535 Whirlpool Refrigerator âŁCompressor Relay and Overload Start Kit is a small but essential component that enables the compressor to start reliably and protects it⣠from electrical â˘faultsâ andâ overheating. By combining⢠a start â¤relay and an overload protector, the kit helps⤠ensure consistent compressorâ operation, maintain proper cooling performance, âand reduce the risk of more extensive compressor damageâ that can âlead⢠to costly repairsâ or premature appliance failure.
Accurateâ diagnosis and targeted replacement are criticalâ when⣠this kit is suspected âto be the source of â˘a refrigeration issue. Symptoms such as a humming compressor that fails â˘to start, intermittent coolingor overheating can indicate a faulty⣠relay âor â¤overload device, âbut â¤similar â¤symptoms may also stem â˘from other âŁsystem components. Confirming the⣠problem⤠through proper testing or professional evaluation minimizes needless parts⤠replacement andâ restores safe, efficient âŁoperation.
When replacement is required, using theâ correct part and⢠following manufacturer specifications or professional installation practices helps preserve system âreliability and extend the service⢠life âof the refrigerator. Timely, informed action-whether by a qualified technician or âŁa educated owner-supports consistent cooling performance andâ helps avoid âmore notable⤠damage and expense down the line.
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
.
