LiftMaster K03-8024-D 24V Reversing Contactor for Commercial Door Operators
The LiftMaster K03-8024-D is a 24V reversing contactor replacement used in select LiftMaster commercial door operator electrical systems. It is part of the motor control circuit and is responsible for switching the operator between directions when the control board or station commands open or close movement.
This part is usually replaced when the original contactor is worn, overheated, stuck, or no longer pulling in reliably. It is a service component for commercial equipment, not a plug-in accessory, so the operator model and wiring diagram must be verified before ordering.
What This Part Does
A reversing contactor routes power through the motor circuit so the operator can run in the open or close direction. In a properly wired operator, the contactor works with the control board, limit switches, safety circuits, brake circuit, and operator controls to provide controlled motor operation.
This part should be replaced only after confirming that the correct control voltage is present and that the original contactor, wiring, and motor circuit match the replacement. A new contactor can be damaged if the operator has a shorted motor winding, loose wiring, failed brake, water intrusion, or incorrect voltage.
Common Symptoms and Service Use
- Operator hums or clicks but does not run in one direction
- Contactor coil does not pull in even when the control circuit is calling for movement
- Visible pitting, overheating, or burned contactor terminals
- Intermittent open or close operation on a commercial operator
- Replacement after electrical enclosure service, surge damage, or contactor wear
Compatible With
The K03-8024-K is used with select LiftMaster commercial door and gate operators where the operator parts diagram calls for this contactor or a related number. Compatibility depends on operator family, control voltage, contactor layout, and production generation.
Common Compatible Products and Operator Families
- Select LiftMaster commercial door operators using a K03-8024-D reversing contactor
- Select LiftMaster commercial door operator electrical boxes with 24V contactor control
- Commercial jackshaft, hoist, trolley, and industrial door operator applications when the parts diagram calls for K03-8024-D
- Operator systems listed under 03-8024-D contactor references
- LiftMaster commercial operators with matching coil voltage, terminal arrangement, and mounting footprint
Additional Applications to Verify
- Related commercial operator control panels where the OEM parts breakdown shows 03-8024-D
- Service replacements for matching 24V reversing contactor assemblies in LiftMaster commercial door operator families
Important Compatibility Notes
- Do not assume compatibility with every SL, BG, or commercial door operator model.
- Match the original contactor label and operator wiring diagram before ordering.
- K03-8024-K and K03-8024-D are both 24V reversing contactor listings, but they should not be treated as interchangeable unless the parts diagram supports the substitution.
- This is not a remote, receiver, wall station, safety device, or residential garage opener part.
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Reversing contactor / mini contactor |
| Part Number | K03-8024-K |
| Related Number | 03-8024-K / 03-11112 style references |
| Application | Motor direction control in select commercial door and gate operators |
| Control Voltage | Commonly listed as 24V control coil applications |
| Compatible Operator Type | Select commercial door and gate operators |
| Notes | Match coil voltage, terminal layout, mounting style, and parts diagram. |
Also Known As / Related Part Numbers
This part may be searched under several part-number formats, older listing numbers, catalog references, or related component numbers. Related numbers are included to help identify the correct item, but they should not be treated as interchangeable unless the operator parts diagram supports the match.
- K03-8024-D
- 03-8024-D
- 038024D
- 03-8024D
- 38024D
- LiftMaster 24V reversing contactor
- LiftMaster contactor 24V reversing
Technician Note
Confirm the exact contactor style before ordering. A contactor with the same physical size may still have a different coil voltage, terminal arrangement, auxiliary contact block, or mounting base. If the original part is badly burned, inspect the wiring harness and motor leads before installing the replacement.
Before Ordering, Confirm
- The original contactor part number or replacement number matches the product being ordered.
- The operator model, voltage, phase, and control-circuit voltage match the parts diagram.
- The contactor coil voltage, terminal layout, mounting footprint, and auxiliary contact setup match the original part.
- The operator is disconnected from power before the electrical enclosure is opened.
- The failure is not being caused by a shorted motor lead, damaged wiring, bad limit circuit, failed brake, or incorrect control input.
Professional Advisory
This is an electrical service part inside a commercial operator enclosure. Disconnect power before service and use a qualified gate or commercial door technician for diagnosis or replacement. Do not bypass limits, safety devices, monitored entrapment protection, or operator interlocks to make a failed control circuit operate.
Important Ordering Warnings
- Reversing contactors are electrical components and should not be selected by appearance alone.
- Similar LiftMaster contactors may have different coil voltages, terminal layouts, or auxiliary contacts.
- Do not bypass interlocks, limits, safety circuits, or operator protection devices to make a contactor operate.
- Repeated contactor failure can point to motor, brake, wiring, voltage, or control-board problems that should be corrected first.
Questions & Answers
What is the K03-8024-D used for?
The K03-8024-D is a 24V reversing contactor used in select LiftMaster commercial door operator motor-control circuits.
They are related 24V contactor listings, but they should not be treated as interchangeable unless the operator parts diagram confirms the match.
What should be checked before replacing this contactor?
Check the original part number, coil voltage, contact layout, terminal wiring, mounting style, operator model, and wiring diagram.
Can a failed contactor cause one-direction operation?
Yes. A worn or failed reversing contactor can cause an operator to run in only one direction or fail to respond even when the control circuit is calling for movement.
Should the motor circuit be inspected too?
Yes. Burned contacts, repeated failure, or chattering can point to voltage, wiring, motor, brake, or control-board problems that should be corrected before installing a new contactor.
