4387535⤠Whirlpool Refrigeratorâ Compressor Relay⤠and Overloadâ Start Kit is â˘an electromechanical service component designed to provide starting âassistance and thermal/current protection for⣠a ârefrigerator’s hermetic compressor.â The kit typically combines a start relay, which momentarily provides current to the compressor’s start winding, âand⤠an overload âprotector, whichâ opens the circuit when the compressorâ draws⤠excessive⤠currentâ or âreaches a critical temperature. As a⣠replacement part itâ is supplied âto restore or maintain reliable startingâ and protection functions in âsingleâphase compressor drive circuits.
Inside the⢠appliance âthe relay and overloadâ device are part of âthe compressor’s electrical â˘path and interact⣠directly with âthe compressor motor, the⤠thermostat or⣠control boardand theâ supply wiring.On a call for cooling the relay engages the start circuit long⤠enough âto develop torque â¤and accelerate the motor to âŁoperating speed; once⤠running, theâ relay disengages⢠andâ the compressor continues on the run winding. the â¤overload monitors â¤motor⢠current and internal temperatureâ and â˘interruptsâ power⢠when theâ motor is at â˘risk of damage, preventing sustained overcurrent âconditions. the assembly isâ usually mounted â¤on or⣠near the compressorâ terminal housingâ and sits at âthe interface between⢠the â¤sealedâ refrigeration âŁsystem and âthe appliance’s âcontrol electronics.
In⣠thisâ article âreaders will find⢠a technical description of how the 4387535 relay âandâ overload kit functions,guidance on⤠model and electrical âcompatibility,typical failure modes and symptoms to âŁwatch for â(forâ example humming,rapid cycling,inabilityâ to start,or intermittent operation),and practical⣠troubleshooting tests a technician can perform âwith common tools (visual inspection,continuity/resistance checks,and controlled⤠amp/voltage⢠measurements).The pieceâ will also cover safe âŁreplacement considerations – â˘matching ratings and terminal âconfiguration, proper mounting and wiringandâ when a relay replacement is unlikely to resolve a âŁlocked or mechanically⣠failed compressor – â¤so technicians, â˘engineersand appliance⣠owners âŁcan make informed ârepair decisions.
Table of Contents
- Function and⤠roleâ of theâ compressor relay âŁand⣠overload start âkitâ in Whirlpool refrigeration⢠systems
- How the â4387535 Whirlpool Refrigerator⢠Compressor Relay⤠And âOverload Start Kit â˘operates⤠inside the compressor startâ circuit
- common failure⢠symptoms,electrical signatures,and diagnostic measurement points âfor relay/overload faults
- Compatibility matrix,replacement considerations,andâ stepâbyâstep âŁinstallation with âtroubleshooting diagnostics for⢠Whirlpool â¤models
- Q&A
- Future âŁOutlook
Function and role of â˘the âcompressor ârelay âand âŁoverload start⣠kit in Whirlpool refrigeration systems
The⤠4387535 Whirlpool refrigerator â˘Compressor Relay And Overload Start âŁKit houses two complementary protection and starting components: a start relay that applies a momentary âelectrical path to the compressor motor’s start winding,and a â˘thermal overload that âinterrupts current if⤠the motor overheats or draws excessive current. Theâ start relay â provides âŁthe âtransient boost needed to overcome âcompressor⢠inertiaâ and âthen disengages once the â¤motor reaches normal⣠running âŁspeed; the overload protector is a temperature- â¤or current-sensitive device wired in seriesâ with the motor that opens â¤the circuit under fault conditions toâ prevent winding damage.⣠In âpractice, a failed relay typically produces clicking orâ continuous humming without â¤compressorâ rotation,â while a tripped overload produces an openâ circuit and⢠a â˘compressor âthat won’t receive power until the overload cools or is â¤replaced.
- Common âsymptoms: â¤repeated⢠clicking at the back of the refrigerator, compressor âŁhum without start, â¤refrigerator temperature riseor intermittent starting.
- Behavior under fault: relay âfailure causes failed starts; overload opening prevents⤠damage but may⣠mask âunderlying start problems.
- Compatibility consideration: kits are matched to specific Whirlpool âcompressor electrical characteristics; incorrect replacements can reduce start âŁtorque or allow overheating.
Techniciansâ diagnose these components by isolating the compressor, checking relay continuity and switching behavior, âand â¤verifying⢠that the overload provides a⢠closed âpath at ambient⣠temperature⣠and opens⢠underâ overcurrent/overtemperature conditions. Replacing the relay and overload⢠together withâ the 4387535 kit restores âthe coordinated âtiming and âŁprotection designedâ for the original compressor motor;⣠practical examples include swapping the kit during confirmed hard-start âŁsymptoms or when measurements show âŁabnormal inrush current or â˘open-circuit âoverloads. For safe, â˘reliable repairs,⤠match the kit to the appliance model and confirm compressor winding resistances âŁbefore⤠and after replacementâ to rule⢠out motor faults.
| Item | Description |
|---|---|
| Start⣠relay | Provides temporaryâ connectionâ to the start âŁwinding to developâ initial âtorque,⣠then⣠disengages for⣠normal run operation. |
| Overload âŁprotector | Thermal/current device âthat âŁopens the motor circuit when overheating or excessive current isâ detected toâ protect windings. |
How the 4387535 Whirlpool⤠Refrigeratorâ Compressor Relay⤠And Overload startâ Kit⣠operates âinside⤠the compressor start circuit
The 4387535 Whirlpool âŁRefrigerator Compressor⢠Relay And Overload Start Kit⤠functions as the combinedâ start-assist⤠and protector âwithin theâ compressor âstart âcircuit. When âthe thermostat closes âand line voltage âis applied, the â¤relay elementâ provides a âŁtimed or momentary feed⤠to the â˘compressor’s start winding so the motor⤠canâ overcome initial inertia⢠and accelerate to runningâ speed; once the motor approaches it’s normal RPM the relay âopensâ and the compressor â˘continues âon âtheâ run winding alone.The overload âcomponent monitors motor current andâ case âtemperature â˘and will open the compressor circuit under sustainedâ overcurrent or âŁoverheating conditions to protect⣠the hermetic âmotor from damage.
Understanding how this assembly interfaces with the compressor helps diagnose failures and verify compatibility: the kit connects to the compressor’s common/start/run terminals and is â¤a direct-replacement âŁstyle module for compatible âWhirlpool/MAYTAG models that âuse the same terminal arrangement and mounting.â Common âfield tests⢠include verifying continuity through the overload (openâ = failed) and âobserving âwhether the relay makes a momentary â˘connection⣠at start, while an increased âamp⣠drawâ or a âcompressor âthat hums but never starts points âto a âfailed relay or a stuck overload.⢠Always disconnect mains âpower before performing tests⤠or replacements; technicians typically replace the âŁmodule if ârelay switching is absent,â the overload âis open at ambientor the â¤unit cycles frequently under normal load.
- Humming compressor that âdoesn’t start or requires several â¤attempts to start.
- Intermittent starts orâ long âcrank times followed by normal operation.
- High current draw or frequent â¤tripping⢠ofâ branch circuit âbreakers.
- Overload open to âŁcontinuity check (indicative of thermal â¤tripâ or internal failure).
| Item | Description |
|---|---|
| Part | 4387535â Whirlpool⢠Refrigerator Compressor Relayâ And Overload Start Kit |
| Primary function | Momentary start âwinding feed + â¤thermal/current⤠overload protection |
| Interface | Connects âtoâ compressor⣠Common/Start/Run terminals; âreplaces like-for-like on compatibleâ models |
Common failure⢠symptoms, electrical signaturesand â˘diagnostic âmeasurement âpoints for ârelay/overloadâ faults
The 4387535 Whirlpool Refrigerator Compressor Relay âAnd Overload Start Kit replaces the relay and â˘thermal overload that⢠connect and protect â¤the compressor start winding.Those components perform two functions: the relay providesâ a temporary âconnection or boost to the compressor start â¤winding â¤to achieve initial torqueand the overload⢠opens the circuit if⣠the compressor â¤draws âexcessive current or â˘overheats. Failures of the relay/overload assembly â˘typically present as a compressor that hums but does not âŁstart, âintermittent starting, rapid on/off cycling, âŁor a âŁunit that only âŁstarts âafter â˘several attempts; âŁthese behaviors⣠reflect either a failed âstart path (open relay or degraded start device) or an overload â˘that is tripping âor remaining âŁopen. The kit is âintended to be compatible with compressors âŁthat⤠use â˘the same terminalâ layout âand electrical characteristicsâ as the OEM â˘module identified by that part number, so âconfirm terminal arrangement â˘and rated âvoltage before replacing the⣠assembly.
Diagnosing relay/overload faults usesâ a âcombination â¤of DC/AC âŁresistance⣠checks â˘and live measurements at the compressor terminals. âWithâ power removed, verify continuity through the overloadâ (closed at â˘ambient) and check â˘the relay coil or PTC element for⢠expected low resistance orâ continuity; an â˘open circuit indicates a failed relay. Measure resistance between the âcompressor terminals labeled⣠S â(start),R â (run),and C (common) to âconfirm the start/run ratio remains within⤠typical⢠motor expectations-an open âor shorted winding⢠suggests a motor faultâ ratherâ than theâ relay assembly. â¤under power, measure⤠line voltage âto the compressor and the control voltage âŁto the ârelay; a full line⤠voltageâ present with no start âŁand low inrush⢠current â¤suggests âŁthe startâ path âŁis not engaging. For practical troubleshooting,isolate the relay/overload from the âcompressor when possible,record resistance and voltage values,and⢠compare them to known-good readings⤠or the appliance service manual â¤before replacing⣠parts.
- Humming/no start: check for mains voltage at compressor, then⣠continuity throughâ relay/start device âand overload.
- Intermittentâ start â˘or rapid âŁcycling: monitor âoverload⣠continuity and ambient⣠temperature; look for thermal trip or marginal contacts.
- Clicking relay but âno run: measure inrush current and start winding continuity; clickâ withâ low inrush usually⤠indicates failedâ start path.
- Ground faults or â¤shorts: measure insulation⤠to chassis fromâ each â¤terminal;â anyâ low resistance⣠to ground indicates a motorâ fault.
| Item | Description |
|---|---|
| Relay / Start device | Should show low resistance orâ expected continuity; open or shorted âelement indicates replacement required. |
| Overload âŁprotector | Continuity at â˘ambient â(closed). ifâ open at âambient or trips quicklyâ under normal conditions,the â˘overloadâ is faulty or it is responding to an upstream problem. |
| Compressor⢠terminals (S, R, C) | Measure resistance ratios between S-R, S-Cand R-C. An open or shorted winding points to motor â¤failure ârather than relay/overload. |
Compatibility matrix, replacement considerationsand stepâbyâstep installation with troubleshooting diagnostics⤠for Whirlpool models
The 4387535 Whirlpool â˘Refrigeratorâ Compressor Relay And⣠Overload Start⤠Kit replaces theâ start relay and thermal overload âthat control and protect âthe⢠compressor’s start winding on threeâterminalâ hermetic compressors.â The start â˘relay provides the brief connection to the start windingâ necessary to develop â˘torque âat motor⢠start,while âthe overload⤠protector opens the circuit under sustained overcurrent â¤or excessive temperature⣠to⣠prevent motor damage. Failed⤠relaysâ or âŁoverloads typically produce symptomsâ such as a âhumming compressor that won’t âstart, repeated clicking of aâ relay, a compressor that starts âintermittentlyor abnormally highâ inrush current; â¤theseâ behaviors are diagnostic indicators â¤that the⢠start circuit âhardware – not necessarily theâ refrigerant charge or compressorâ internals – is the⢠likely⤠fault.
when replacing the start kit on whirlpool units, verify âterminalâ labeling (R, S, C),⢠mounting style,â and voltage/current ratings to ensure physical and electrical compatibility ârather than relying solely on modelâ numbers. â˘For installation⣠and troubleshooting: cutâ power ⣠before⢠accessing the⢠compressor, note and photograph terminal positions, swap in âthe new kit, then monitor startâ attempts âand line current. If⣠the âcompressor still fails to â˘start after a proper replacement, perform targeted âdiagnostics â- verify correct line âvoltage at the compressor⤠during start, check continuity throughâ the overloadand â˘measure starting current with a clamp ammeter to distinguish an electrical âstartâcircuit âfailure from a seized or mechanically defective compressor.
- Safety first: disconnectâ mains power and allow capsâ to âŁdischarge.
- Locate the relay/overload⤠at theâ compressor base, remove âterminal â˘connectors in orderand⣠match RâSâC when installing the ânew kit.
- Restore âpower briefly to âobserve start behavior⤠while measuring â¤inrush current; ânormal startâ current â˘spikes 5-8Ă running current on manyâ small hermetic compressors⤠-⤠persistent excessive spikes indicate motor orâ systemâ issues beyond the âstart â¤kit.
- If the compressor â¤only⤠hums after replacement, swap terminals back⣠and test âthe âoverload for open âŁcircuit at ambient temperature and examine for heat discoloration⤠or melted housings as âsigns ofâ previous overload trips.
| Item | Description |
|---|---|
| Terminal IDs | R =â Run, âS = Start, C = common; correct mappingâ is required for proper start sequencing. |
| Common symptoms | Humming, no start, ârepeated clicks, intermittentâ starts, â¤or overheating of relay/overload housing. |
| Quick diagnostics | Verifyâ line voltageâ toâ compressor, âcontinuity of âoverloadand measure starting current withâ a⢠clamp ammeter during initial start⢠attempts. |
Q&A
What is theâ 4387535 Whirlpool Refrigeratorâ Compressorâ Relay and Overload Start kit?
The 4387535 is a start kit â˘sold âŁfor â˘many Whirlpool-family⢠refrigerators that contains the compressor start⢠relay and⤠thermal overload â¤protector. The relay provides theâ brief extra â˘torque needed to start the âcompressor âmotor and the overload protectsâ the compressor from drawing âexcessive current âor overheating. Together⤠they ensure reliable âmotor startup and automatic protection during fault âconditions.
What symptoms indicate the relay/overload kit â˘has failed?
Common symptoms include a refrigerator that is not âcooling with⤠the⢠compressor âattempting to start (humming, âclickingor rapidly cycling), a compressor that won’t start at allor a compressor that âruns⤠for â˘a âŁshort time then trips off and refuses to â¤restart â˘for a while. You may â¤also notice the compressor âis very hot⤠to the touch. These symptoms strongly suggest theâ start relay/overload assembly âis â˘faulty or intermittent.
How can I test the relay âand overload to â˘see⢠if â¤they are bad?
First unplug âthe⤠refrigerator. Remove the relay/overload from the compressor. A basic bench âtest âwith âa multimeter can check for open⢠circuits-the relay/overload should âshowâ continuity where â˘expected (not âŁopen). A â¤faulty relay often shows no continuityâ or⤠erratic resistance.⣠Another quick field test: with the â¤relay removed, gently shakeâ it-if youâ hear loose âŁparts it’sâ likely bad.⤠Avoidâ applying âmainsâ voltage to bench-test unless you are⢠trained; if unsure,⤠have a trained technician performâ live tests or âŁreplace the unit.
Isâ the 4387535 kit compatible with myâ refrigerator?
4387535 âis⢠a common OEM start kit âused âon⢠many Whirlpool-family⤠models (Whirlpool, Maytag, KitchenAid, Kenmore, etc.),â but ânot every model⤠uses the same â˘part. âAlways verify⤠compatibility⣠by⤠checking your refrigerator model ânumber âŁagainst the part cross-referenceâ from the manufacturer⢠orâ a trusted parts supplier before â˘purchasing.⣠Installing the âwrong part can⤠causeâ damage orâ fail⤠to resolve the issue.
Howâ do I install the 4387535 âstart kit?
turn off and unplug â˘the refrigerator. Access the compressor area (usually through âa rear bottom access⢠panel). â˘Carefully remove the old relay/overloadâ from the compressor â˘terminals-note terminal âpositions-and disconnect any wiring harness clips. Install the new kit by pushing itâ onto âthe âcompressor⤠terminals âandâ reconnecting any â¤harnesses â˘or retainingâ clips. Replaceâ the accessâ panel and restore power.⤠If you’re not cozy working â¤near⤠the compressor or electricalâ components, hire a qualified appliance technician.
Can I run âthe compressor without theâ relay or bypass the relay to â¤test the compressor?
No.⢠You should not run âŁorâ attempt to start a refrigeratorâ compressor by bypassing⢠the relay or overload. Doing so⤠can âdamage the compressor motor and void warranties,and it’sâ aâ safetyâ hazard. if you need to test compressor operation beyond multimeter checks, have a qualified technician perform a⢠safe and âŁcorrect test.
How long do relays/overloads lastand âshould â˘I replace both parts âat⤠once?
There is no fixed lifetime; relays and overloads⣠can fail due to age, thermal stress,⢠or⣠electrical issues. âŁIf one component âfails, the matching component â˘in the kit might⤠potentially be â˘aged â˘too, so replacing the completeâ startâ kit is recommended. â˘Installing both new⢠partsâ together âŁreduces the âchance of near-term failureâ and is standard⣠practice when â¤the⢠start components are identifiedâ as the âproblem.
Are⤠there any âsafety precautions I should⤠follow âŁwhen replacing âŁthisâ part?
Yes-always unplug⤠the refrigerator before⤠beginning⢠work.⤠Wearâ gloves⢠and âeye protection âŁto⣠avoid cuts and contact with hot surfaces.Be carefulâ when handling compressor âŁterminalsâ and wires; âŁdo not force â˘or bend⤠terminals. If⤠you smell burnedâ wiring âor see oil around the compressor, stopâ and call a technician-these signs can indicate âmore â˘serious â¤compressor or systemâ faults that a start⤠kit â˘replacement won’t fix.
Future Outlook
The 4387535 Whirlpool Refrigerator â˘Compressor Relayâ and Overload Start Kit plays a criticalâ role⣠in reliably starting and protecting the refrigerator compressor. âBy providing âthe âŁinitial⤠start torque â˘and interrupting â˘current when the motor overheats, this kit helps âmaintain âŁefficient compressor operation, prevents motor damageand âsupports consistent cooling performance throughout the⤠appliance’s service⢠life.
Timely âŁand â¤accurate diagnosis of ârelay andâ overload function is ânotable as âŁsymptomsâ such as⣠humming, failure to start, âerratic cycling, âorâ frequent⣠overheatingâ can signal component failure. Proper âtesting and confirmation of the âroot cause ensure that theâ 4387535 start kit is installed only when appropriate,⣠avoiding unnecessary parts changes and preventing misdiagnosis⤠thatâ could⣠leave underlying issues unresolved.
When replacement is required, using â˘the correct âŁ4387535 âWhirlpoolâ Refrigerator âCompressor Relay And Overload Start⣠Kit and following recommended âinstallation âpractices⣠helps restore âreliableâ operation and reduces the risk of further compressor damage. For those unsure â¤about diagnosis or installation, âconsulting a qualifiedâ service âtechnician is advisable âto ensure safety, correct compatibilityand long-term performance ofâ the refrigerator.
Professional Appliance Service
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