4387535 Whirlpool Refrigerator Compressorâ Relay And⤠overload Start⤠Kit âŁis â˘a combined âŁstart relay and thermal â¤overload⢠protector designed⢠for⣠use âwith singleâphase hermetic refrigerator compressors.The kit typically⣠contains a current orâ voltageâsensingâ start deviceâ (relay or PTC style) that âmomentarily⣠energizes the compressor’s start winding and a â˘thermal/current overload element⣠that âopens the â¤compressor supply if the motor draws âexcessive currentâ or exceeds safe operating temperature. Physically the assembly mounts at or near the compressorâ terminal block and is â¤wired⢠in series with the compressor’s common, start and â¤run connections.
Inside the appliance the relay and overload sit âŁbetween theâ incoming line and the compressor motor⣠and interact directly with the compressor’s start and run windings. Theyâ also interface indirectly with the thermostat âor control board, âthe line powerand any⢠start capacitor present on larger systems; the ârelay provides the shortâduration extra torque required to bring the compressor âup⤠to speed and then⢠releases the start â˘winding, while⤠the âoverload â˘protects the motor âfrom âŁsustained overcurrent or overheating. Becauseâ they areâ a primary point of electrical control âand protection for âthe compressor, âthier conditionâ affects starting â˘torque, â¤running currentand overall â˘cooling performance.
Inâ this⣠article âŁyou will findâ a technical description âŁof how the⣠4387535 relay andâ overload operate, how to verify⢠compatibility⣠with specific Whirlpool models and compressor types,â common failure symptoms to âwatch for⣠(for example humming⤠without âstarting, highâ running amps, intermittent operationor tripped circuits)and stepâbyâstep troubleshooting methods including⤠visual inspection, continuity and resistance âchecksand amp/voltage tests⢠during âstart.⢠The articleâ also covers practical âŁreplacement⣠considerations such as matching terminal⤠layout and electrical ratings, correct mounting and wiring practicesand safety precautions to take before âservicing â¤the compressor circuit.
table of Contents
- Function⣠and Role of â¤the Compressor Relay and Overload Start Kit in Whirlpool Refrigeration â˘Systems
- How the 4387535 Whirlpool âRefrigerator âCompressor Relay And Overload Start Kit Operates Internally and Interfaces âwith the âŁCompressor
- Common Failure Symptoms and Electrical⤠Signatures âof a Faulty Compressor Relay/Overload Start â¤Kit
- Replacement Considerations âand Step-by-Stepâ installation Guidelines for the 4387535 âKit
- Q&A
- insights âŁand Conclusions
Function andâ Role of the Compressor Relay âŁand⣠overload âStart Kit in Whirlpool Refrigeration Systems
The 4387535 âWhirlpool Refrigerator Compressor Relay And Overload Start Kit combines a start relay â¤and thermal overload âprotector to manage the compressor’s start-up and protect âitâ during run conditions. In âsingleâphase âhermetic refrigeration compressors the start relay delivers⣠a short-duration connection toâ the start â¤winding (or âintroduces⢠the start circuit âŁvia a PTC/currentâsensing âelement) to generate the required starting torque,⣠while the âoverload opens the compressorâ circuit if internal âtemperature orâ current exceed safe limits.⣠When operating normally theâ relay â˘engages â˘only for a fraction â¤of âa â˘second atâ startup âand then opens once the compressor âŁreaches ârunning speed; the overload is passiveâ until a âsustained overcurrent or⣠overheating conditionâ occurs.⤠Typical failure modes include a stuck relay that prevents the start â˘winding from⤠engaging,â a PTC that no longer⣠changes resistance correctlyor an â˘overload that âhas⣠tripped or become openâcircuit, all of which can present as click/hum/noâstart behavior⣠or repeated cycling âunder load.
Compatibility âŁand practical application require matching the âŁkit⣠to â˘the âcompressor’s electrical â˘characteristics, terminal layoutand mounting method rather than assuming worldwide interchangeability.Technicians âshould confirm terminal design â(twoâ orâ threeâterminal compressors), nominal voltageand compressor lockedârotor current so the relay and â˘overload will operateâ within the âintended time/current thresholds;â usingâ an incorrectlyâ rated start relay can cause excessive starting stress or failure to⤠start, while an incorrectly rated â¤overloadâ may nuisanceâtrip or fail to protect.⣠For practical diagnosis, verify the⢠symptoms below⣠and inspect the â¤relay âŁforâ physicalâ damage orâ heat discoloration; replacing the start kit isâ a common, costâeffective repair beforeâ considering compressor replacement, especially when the compressor hums or clicks but does âŁnot run continuously.
- Common⢠symptoms: repeated clicking, âŁhumming without full â˘run, slow or no âŁtemperature recoveryor tripping circuit âŁprotection.
- Behavioral clues: ârelay pullâin only at startup; âoverload âopens onlyâ afterâ overcurrent/overtemperatureâ conditions.
- Compatibility checks: â˘terminal count, voltage rating, âand âphysicalâ mounting must⤠match the compressor and wiring harness.
| Item | Description |
|---|---|
| Part number | 4387535 Whirlpool Refrigerator Compressor âRelay And Overload Start Kit |
| Primary⢠function | Provide⤠start âtorque via start circuit and protect compressor fromâ sustained overcurrent/overtemperature |
| Typical failure indicators | Clicking/humming/noâstart, visible âheat⣠damage, open continuity on relay orâ overload |
How â¤the 4387535 Whirlpool Refrigerator⤠Compressor Relayâ And âOverload Start Kitâ Operates Internally and Interfaces âŁwith the Compressor
The 4387535 Whirlpool Refrigerator Compressor âRelay And Overload start â¤Kit combines a⣠start âŁassist device âandâ a thermal overload protector into âŁa compact assembly that interfaces directly with the compressor terminalâ cluster. The⤠start portion (implemented â˘either as a current-sensing relay or a solidâstate/ â¤PTC element depending on the manufacturing run) momentarily provides âthe⢠extra torque needed to âconnect or boost the⢠compressor’s start winding⤠until the motor reaches normal speed; the overload is a temperatureâsensitive deviceâ placed in series with the common line that opens the⢠circuit âif⣠current and heatâ indicate a locked rotor or severe âoverload. Technicians â˘install the kit by plugging or âŁbolting it onto the compressor’s terminal cover and wiring it to the⤠compressor’s labeled terminals (typically S, Rand C), so the kit directly â˘controls the start and protects the motor without âŁadditional control logic.
Internally, the relay reacts to voltage andâ current conditions toâ switch âthe start windingâ in and⣠out of theâ circuit within a few hundred milliseconds, âwhile the overload uses a bimetallic or thermally responsive â˘element to provide timeâdelayed protection against sustained overcurrent âŁand overheating. Compatibility⤠depends âon â¤terminal layout, âoperating voltageand compressor⣠design; replacing a failed relay/overload⤠with the 4387535 kit typically ârestores correct start timing âand motor protection provided the compressor’s âelectrical specifications match the kit’s ratings. Forâ practical troubleshooting, observe symptoms such âas prolonged humming⤠or repeated trip cycles and verify terminal continuity and coil resistance beforeâ replacing the kitand always confirm that the replacement part’sâ terminal âmapping and rated voltage match theâ appliance model.
- Common symptoms⢠indicating â¤kit or related â˘compressor start issues: hard start/humming,⣠no â¤start with warm compressor, repeated â¤overload⢠trips,â or visible heatâ discoloration at terminals.
| Item | Description |
|---|---|
| Start⤠relay | Provides⢠shortâduration connection or impedance change to engage âthe compressor’s start winding and âŁincrease starting torque. |
| overload protector | Thermalâ device âin series with the common âterminal⣠that opens under sustained âovercurrent/overtemperatureâ to âŁprotect the â˘motor. |
| terminal mapping | Interfaces âŁwith S, Rand C ⣠on the compressor; verify mappingâ and voltage before installation. |
Common Failure⣠Symptoms and electrical Signatures of aâ Faulty Compressor Relay/Overload Start⢠Kit
The â˘4387535 Whirlpool Refrigerator Compressor Relay And⤠Overload Start Kit combinesâ a start⤠relay (or âPTC start device) â¤with a thermal â¤overload⢠protector âŁto manage engagement of the compressor’s start winding and to âdisconnect â˘the âcompressor under excessive current or temperature conditions. When functioning correctly theâ relay supplies âa timedâ inrush to the start winding to⤠achieve âŁinitial rotor acceleration, while the âoverload monitors motor current/temperature and opens the circuit â¤if âthe⢠compressor draws sustained excessive âŁcurrent. â¤Failures in â˘either component â˘produce specific electrical signatures-no inrush current or⢠intermittent inrush,an open circuit at theâ overload,or abnormal âvoltage â¤sag⢠at the compressor âŁterminals-that help âŁseparateâ a defective â˘start⤠device fromâ a â˘failing compressor motor⣠or wiring fault.
- Clicking relay with no âstart: relay âenergizes but no inrush current; often a failed âstart device or disconnected start winding.
- Humming compressor that won’t start: relay may supply part of the start â¤circuit but not longâ enough; measured locked-rotor current can be unusually high.
- Openâ overload⣠protector: continuity check shows infiniteâ resistance; compressor remains dead until⤠overload coolsâ or replacement occurs.
- Excessive supplyâ voltage drop âwhen âstarting: indicates high âstarting⣠current âŁor poor connections; can⢠trip overload or indicate failing start â˘components.
| Item | Description |
|---|---|
| Start ârelay⣠signature | No measurable âinrush toâ start winding or intermittent âŁinrush during â˘start â¤attempts. |
| Overload⤠condition | Open circuit (infinite ohms) on continuity check; may reset when cooled. |
| Current/voltage observation | High locked-rotor current or large voltage sag âat compressor terminals during start. |
For practical⣠diagnosis use a clamp meter andâ a multimeter to compare observed startâ current and⤠winding⣠continuity to⢠expected behavior: âa healthy start device produces a distinct transient inrush followed by normal running current, while a failed device shows no âtransient or repeated short attempts with high current. â˘If the â˘electrical⣠signatures point â˘to â¤the start kit-consistent lack of inrush, open overload, âor ârelay⢠charring-replacement of the 4387535-style start and overloadâ assembly⤠is typically the correct â¤next step,â though verifying âŁharness compatibility and âŁconfirming the âcompressor is⤠not mechanically seizedâ (by⢠checking resistance acrossâ compressor terminals andâ motor temperature) will avoid needlessâ part changes.
Replacement Considerations and Step-by-Step Installation Guidelines for the 4387535 Kit
The âŁ4387535 Whirlpool Refrigerator âŁCompressorâ Relayâ and â˘Overload Start Kit combines the start relay and thermal overload protector âthat control the compressor start winding and protect the motor âfrom excessive current and heat. âŁIn normal⢠operation the relay provides â˘an initial boostâ to engage the compressor’s start winding, while the overload opens the circuit if⢠the⤠motor draws sustained high⢠current or âŁreaches⣠a thermal fault; âŁreplacingâ both âŁcomponents âas âŁa matched kit restores the â¤intended startâ sequence and protection. Verify mechanical and electrical compatibility with the⣠refrigerator model and compressor terminal â˘layout (Common, â˘Start, run) before installationand⤠confirm nominal⣠supply voltage and terminal orientation to avoid⣠miswiring.
Install the kit â˘using disciplined procedure: âisolate mains power, label and photograph wire positions, then remove theâ compressor access coverâ andâ the existing relay/overload assembly. Inspect compressor terminals and the rubber boot for âcorrosionâ or damage;â replace⢠the boot if brittle. Mount⣠the new relay/overload so the thermal element⢠maintains âcontact â¤with⤠the compressorâ body per manufacturer orientation, reconnect⤠wires to the matching terminals, secure any retaining clips,⣠restore the access cover, â¤and⤠apply power âbriefly â¤while monitoring âcompressor behaviorâ and⤠amp draw with a clamp âmeter. If the⣠compressorâ still fails to start or draws abnormally⣠high âcurrent after âinstallation,â stop and âperform further diagnostics on the compressor andâ starting capacitor (if âpresent)â rather than cycling power âŁrepeatedly.
- Preparatory âchecks: confirm part cross-reference, disconnect power, photograph⤠wiring.
- Removal: detach⤠wires, remove â˘retaining clips, inspect terminals and âboot.
- Installation: fit new ârelay/overload with correct orientation, reconnect⣠wires to C/S/R, secure assembly.
- Validation: power up, observe start behavior, measure âŁcurrent âŁand temperature, re-check⢠connections if abnormal.
| Item | Description |
|---|---|
| Compatibility | Singleâphase hermetic compressors used in⢠specific Whirlpool models; confirm model cross-reference before replacing. |
| Terminals | Common (C), Start (S),â Run (R) â- match wire positions from the original⣠assembly. |
| Function | Relay â¤provides start boost;⣠overload interrupts on sustained overcurrent/overtemperature. |
Q&A
What â˘is the 4387535 Whirlpool Refrigerator Compressor Relay and Overloadâ Start Kit?
The 4387535 kit is⤠an OEM-style start device for âcertain⢠Whirlpool-family refrigerators. It combines a compressor start relay⣠(or PTC start device) and a thermal overload protector. Together these⢠help âthe compressor â¤get the initial âstart-up torqueâ and protect the compressor from overheating or excessive current.
What âsymptoms â¤indicate the ârelay/overload (4387535) is bad?
Common symptoms include: compressor humming but âŁnot starting, repeated clicking or clicking then silence, refrigerator not cooling âwhile lights⢠and fan work, the compressor running briefly âthen stoppingor the compressor drawing excessive starting current.⢠Physical signs â¤can include burnâ marks, melted plasticor a hot/totallyâ open overload device.
How âcan I check â˘if â4387535 is compatible with my â¤refrigerator?
Check your refrigerator model number (usually âŁon a sticker inside â¤the fresh food compartment, behind a drawer, âor onâ the back) and look up parts on⣠the Whirlpool/Whirlpool Partsâ website or the appliance’s parts diagram. Entering yourâ modelâ will show the correct start⤠kit part number. â¤You can also compareâ theâ old part’s âshape, terminal configurationand mounting â˘points to ensure correct fit.
Can I replace the⢠4387535 myselfand⤠what â¤safety precautions should I take?
Yes, a competent âŁDIYer can usually replace it. Safety âsteps: unplug the â˘refrigerator before working, â¤wear gloves to avoid âŁcuts from sheet âmetal, avoid â¤damaging sealed⣠refrigerant linesand â¤make sure the replacement is the correctâ part. If you’re not comfortable working near the compressor or doing electrical checks,hire a qualified âtechnician.
How do I test the ârelay âŁand overload to⣠no they⣠areâ faulty?
Initial safe tests: unplug the fridge,⢠access the relay/overload on⢠the compressor, visually inspect for damageand test continuity across the overload with a multimeter (overload â¤should normally show continuity when cold). For PTC relays,â simple resistance âchecks are often inconclusive. A proper diagnosis typically uses a clamp⣠meterâ to measure starting current (a failed start device will âŁshow an abnormally low start currentâ and⢠the compressor won’t spin up) or âŁswapping with a known-good start kit. Live âjumpâ tests are risky and âbest left⣠to technicians.
What are the basic steps â˘to replace the 4387535 start kit?
Basic procedure: 1) Unplug the refrigerator. 2) Pull the fridgeâ out andâ remove the âaccess panel âat the back⣠or bottom to reach the compressor.3) Note â¤terminal positions⢠and take a photo. 4) Gently remove the oldâ start kit from the compressor â˘terminals (careful-terminals âŁcan be tight). 5) âInstall the âŁnew kit matchingâ terminals and orientation, secure it in place. âŁ6) Replace the accessâ panel, restore⣠powerand listen⢠for the compressor to start. âIf unsure,consult âŁthe â¤model’s serviceâ manual or call âa â˘technician.
If I replace the 4387535â and the compressor still won’t start,what does⢠that âŁmean?
Replacing the start kit fixes⤠only start/overload faults. âŁIf the compressor still refuses â˘to â˘start, the compressor motor itself⣠may have anâ internal failure (seized start/run windings), â¤there might potentiallyâ be electrical supply issues,⢠or â˘the sealed refrigeration system may be locked up. In that case further diagnosis with a multimeter,clamp meter,or a âtechnician’s compressor test is required; aâ bad compressor oftenâ requires âreplacement by â˘a service technician.
Is an aftermarket or universal start kit acceptableor âŁshould I use OEM⣠4387535?
You can use a reputable aftermarket or universal start kit⣠if it explicitlyâ lists compatibilityâ with your refrigerator model and matchesâ the terminal layout and electrical⤠ratings. OEM parts âŁlike the â˘4387535 âare guaranteed to fit and meet manufacturer specs,â which reduces the risk⣠of fitment or â¤reliability problems. Avoid cheap, non-specified parts and verify âratings before installation.
Insights and Conclusions
The 4387535 Whirlpoolâ Refrigerator Compressor Relay And Overload Start Kit plays a âŁcritical role âŁin ensuring⢠reliable compressor startup and protecting the compressor motor from electrical overloads. â¤By providing theâ initial âtorque to start the compressor and interrupting âpower under⣠damaging conditions,this startâ kit helps maintain â˘cooling performance,prevents premature compressor failure,and contributes to the overall longevity and energyâ efficiency of theâ refrigerator.
Accurate diagnosisâ and timely âreplacement of a faultyâ relay and overload start âkit are essential to â¤address symptoms such as⢠repeated âclicking, inability of â˘the compressor to startor unusual heating at â˘the compressor.Replacing the start kit when it is the confirmed cause⤠of a fault reduces the â¤risk of⣠cascading failures and more costly repairs,⤠while ensuring that the â¤appliance returns âto â˘safe, reliable operation.
When replacement is necessary, selecting the correct â˘OEM- âor manufacturer-specified⢠part â¤and following⣠proper installation procedures-weather â¤performed by a trained technician⣠or a⤠knowledgeable homeowner-helps ensureâ optimal âŁperformance and âsafety. Routine âinspection and prompt attention to starting issues â˘support efficient operation âŁand help protect the refrigerator’s compressor investment âŁoverâ time.
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