Liftmaster 29-40376, RELAY
The LiftMaster 29-40376 relay is an electromechanical switching component used in select commercial gate operator control systems. In an operator such as the SL930, relays can be used to transfer control signals to higher-load circuits, isolate functions, or manage specific operator outputs. A failed relay may leave a function dead, intermittent, stuck on, or chattering under load. However, the same symptoms can come from weak voltage, damaged wiring, failed control-board outputs, bad contactors, or mechanical loading problems. This part should be selected by exact relay reference, parts diagram, and terminal configuration. Because older commercial operators may have been repaired or modified over time, always compare the existing relay and wiring before ordering.
Compatible With
- Compatible with LiftMaster SL930 commercial slide gate operators when the parts diagram specifies 29-40376.
- For use with select LiftMaster commercial gate operator control circuits.
- Related SL930 supplier references list this relay as a service component.
- May be used in industrial slide or swing gate operator circuits only when the wiring diagram calls for this exact relay.
- Not interchangeable with other LiftMaster relays unless coil rating, contact rating, and terminal layout are confirmed.
Features & Specifications
| Manufacturer | LiftMaster / Chamberlain Group |
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| Product Type | Electromechanical relay |
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| Part Number | 29-40376 |
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| Application | Commercial gate operator electrical control circuit |
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| Common Model Reference | SL930 commercial slide gate operator |
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| Related Part Number | 23595-73 in some supplier listings |
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| Notes | Match coil rating, contacts, and terminal layout |
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Also Known As / Related Part Numbers
- 29-40376
- LM-29-40376
- LiftMaster 29-40376
- 23595-73
- Commercial gate operator relay
- SL930 relay
Technician Note
Check for loose spade terminals, heat damage, contact pitting, coil voltage, and whether the relay is being commanded by the control circuit. Do not assume a relay is bad only because the function is not operating.
Before Ordering
- Confirm the old relay part number is 29-40376 or related 23595-73.
- Verify the operator parts diagram, especially on SL930 units.
- Match coil voltage and contact rating.
- Compare terminal layout and mounting.
- Inspect the controlled load for shorts or excessive draw.
Important Ordering Warnings
- Similar relays may not be electrically interchangeable.
- A failed relay can be caused by an overloaded circuit.
- Do not bypass relay contacts to force the operator to run.
- High-voltage control circuits require qualified service.
Professional Advisory
Electrical components should be installed and tested by a qualified gate technician. Disconnect power before service and do not bypass safety devices, overload protection, alarms, or manufacturer-required entrapment protection devices.
Product Questions & Answers
What model is 29-40376 commonly associated with?
It is commonly listed for LiftMaster SL930 commercial slide gate operator service applications.
Is 29-40376 a universal LiftMaster relay?
No. Relay coil rating, contact rating, and terminal layout must match the operator circuit.
What symptoms can a bad relay cause?
Depending on the circuit, it may cause a function to stay off, stay on, chatter, operate intermittently, or fail under load.
What is related part number 23595-73?
Some supplier listings reference 23595-73 as an also-known-as or related number for this relay. Confirm the original relay before ordering.
Should I replace the relay or the board?
The circuit should be tested first. A relay can fail, but the control board output, wiring, or load controlled by the relay may also be the cause.
