Liftmaster 25-4002-5K Overload, 1.8-2.6A
The LiftMaster 25-4002-5K overload relay is a motor protection device used inside select commercial operator electrical boxes. In a starter-controlled operator, the overload is part of the motor protection circuit and is intended to open the circuit if the motor draws too much current for too long. This can help prevent damage caused by a jammed door, stalled gate, failing motor, improper voltage, or incorrect phase condition. This 1.8-2.6A version is selected by amp range, not by operator brand alone. The technician should compare the existing overload label, motor full-load amp rating, operator wiring diagram, and contactor style before replacing it.
Compatible With
Select LiftMaster commercial door and commercial gate operator starter circuits where the parts diagram lists 25-4002-5K or K25-4002-5K; commonly used in lower-current commercial motor applications where the motor full-load amp rating falls within the 1.8-2.6A overload range.
Features and Specifications
| Manufacturer | LiftMaster / Chamberlain Group |
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| Product Type | Thermal overload relay |
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| Part Number | 25-4002-5K |
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| Current Range | 1.8-2.6A |
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| Application | Motor overload protection in select commercial operator starter circuits |
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| Compatible Operator Type | LiftMaster commercial door and gate operators where specified |
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| Notes | Do not substitute a different overload range unless the operator wiring diagram and motor FLA support it. |
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Also Known As / Related Part Numbers
- 25-4002-5K
- K25-4002-5K
- 2540025K
- 25-4002-5
- LiftMaster overload 1.8-2.6A
- LiftMaster thermal overload relay 1.8-2.6 amp
Technician Note
For LiftMaster commercial operator service parts, the safest fitment method is to match the original component label and the model-specific parts diagram. Similar-looking electrical parts can have different ratings, wiring, or software versions.
Before Ordering Checklist
- Confirm the exact operator model and serial information when available.
- Match the original part number or service part number on the failed component.
- Verify voltage, phase, amp range, timing function, or control-circuit requirement before ordering.
- Compare connector layout, mounting style, terminal markings, and wiring diagram.
- Do not bypass safety devices, fire-door controls, or required monitored protection during troubleshooting.
Professional Advisory
This item may be part of a high-voltage commercial door or gate operator system. Electrical testing, motor replacement, transformer replacement, control-board service, overload adjustment, and fire-door operator repairs should be handled by a qualified technician. Never bypass required safety devices or fire-door controls to force an operator to run.
Questions and Answers
What is the amp range for 25-4002-5K?
The adjustment range is 1.8 to 2.6 amps.
Is 25-4002-5K interchangeable with 25-4004-K?
No. They have different current ranges and must be matched to the motor and starter circuit.
What causes this overload to trip?
A tight door, binding gate, wrong voltage, failing motor, incorrect setting, or damaged starter components can cause overload trips.
Can I install a higher amp overload to stop nuisance trips?
No. Oversizing an overload can remove needed motor protection and create a safety hazard.
What should be matched before ordering?
Match the original overload number, amp range, motor nameplate full-load amps, and operator wiring diagram.
