The LiftMaster 25-4008-K overload relay is a protective electrical component used in commercial operator motor circuits. It monitors current draw and opens the control circuit when current rises beyond the selected operating range, helping protect the motor and starter components from overheating or damage. In field repairs, this part is most often replaced when the original overload is damaged, no longer resets correctly, has burned contacts, or no longer matches the motor being used.
Because overloads are selected by amp range, this 5.5-8.0A model should not be swapped with a lower or higher range overload unless the operator wiring diagram and motor nameplate support that change. If the overload is tripping repeatedly, the door or gate system should be checked mechanically and electrically before a new relay is installed.
Compatible With
Compatibility is determined by amp range, motor rating, voltage/phase, contactor style, and the operator parts diagram. Adjacent overload sizes are related but not interchangeable unless the motor data supports the change.
- Select LiftMaster commercial door operators using a 5.5-8.0A overload relay
- Select LiftMaster commercial gate operators using a 5.5-8.0A overload relay
- Commercial motor starter assemblies that specify 25-4008-K or related part numbers
- Control circuit contactor style electrical boxes where the parts diagram calls for this amp range
- Select SL580-150-23-S3 and SL580-150-83-S3 style applications when confirmed by parts diagram
- Select commercial gate operator applications requiring 25-4008 or 25-4008-K
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Overload Relay / Motor Protection |
| Part Number | 25-4008-K |
| Amp Range | 5.5-8.0A |
| Application | Commercial operator motor overload protection |
| Compatible Operator Type | Select LiftMaster commercial door and gate operators |
| Notes | Match amp range, motor FLA, voltage, phase, and parts diagram. |
Also Known As / Related Part Numbers
These numbers and search variations are commonly associated with this part family. Match the actual label, operator model, and parts diagram before treating a related number as a direct replacement.
Technician Note
Always compare the overload range to the motor nameplate full-load amps. Replacing a tripping overload without correcting a binding door, phase issue, or motor problem can lead to repeat shutdowns or motor damage.
Before Ordering, Confirm
- The original overload part number and amp range match this listing.
- The motor full-load amp rating falls within the overload setting range.
- The operator voltage and phase match the wiring diagram.
- The door or gate moves freely without binding.
- The contactor, wiring, and motor have been checked if the overload was tripping repeatedly.
Professional Advisory
Overload relays are part of the operator motor protection circuit. Electrical diagnosis should be performed by a qualified commercial door or gate technician, especially on three-phase or high-voltage operators.
Important Ordering Warnings
- Do not choose an overload by physical size alone.
- Do not install a higher amp range to stop nuisance tripping.
- Do not bypass an overload relay.
- Do not ignore door balance, gate drag, phase loss, or motor problems.
Questions & Answers
It is used to protect the motor circuit on select LiftMaster commercial door and gate operators that require a 5.5-8.0A overload range.
Why does the overload keep tripping?
Repeated tripping can be caused by a binding door or gate, high motor current, incorrect voltage, phase loss, failing motor, damaged wiring, or an overloaded drive system.
Can I replace it with a different amp range?
Only if the operator wiring diagram and motor nameplate support that amp range. The overload must match the motor full-load amp requirements.
Is this used on residential garage door openers?
No. This style of overload relay is used on select commercial operator electrical systems.
What should be checked before installing it?
Check the original part number, amp range, motor nameplate, voltage, phase, contactor style, and mechanical condition of the door or gate.
