LiftMaster K27-8002-D Auxiliary Contact Block Relay, 1 NO/1 NC
The LiftMaster K27-8002-D is an auxiliary contact block used in select commercial door operator control assemblies. It provides one normally open and one normally closed auxiliary contact for control, interlock, or feedback functions tied to the operator starter or contactor system. This type of part is often used where the operator needs an additional contact signal beyond the main power contacts.
Because auxiliary contact blocks can look similar from the outside, the contact arrangement is important. K27-8002-D should be matched to the existing contact block number, terminal markings, and the electrical diagram. It should not be confused with 2NO/2NC contact blocks, primary contactors, motor overloads, or control relays. If a contact block has burned contacts or loose terminals, inspect the contactor and control wiring before replacing only the block.
Compatible With
This part should be matched by the operator model, electrical box, voltage/phase, motor label, and the LiftMaster parts diagram. Compatibility below is based on commonly referenced LiftMaster/Chamberlain commercial door operator parts information and should be verified against the unit being serviced.
- LiftMaster GH 5HP commercial door operators where the parts diagram calls for K27-8002-D or 27-8002-D
- GH5HP electrical box references listing 27-8002-D contact block
- Select LiftMaster industrial-duty commercial door operator contactor assemblies using a 1 NO / 1 NC auxiliary contact block
- Select GH, GT, H, and J style commercial mechanical operators only when the contactor/parts diagram confirms the same auxiliary contact block
- Not interchangeable with K27-8004-D 2NO/2NC or other contact block arrangements unless confirmed by wiring diagram
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Auxiliary contact block relay |
| Part Number | K27-8002-D |
| Contact Arrangement | 1 NO / 1 NC |
| Application | Commercial operator contactor or starter auxiliary contact |
| Compatible Operator Type | Select LiftMaster industrial and commercial door operators |
| Common Confirmed Reference | GH 5HP commercial door operator electrical box |
| Notes | Match the contact arrangement and terminal markings before ordering |
Also Known As / Related Part Numbers
The following numbers and search variations are commonly associated with this listing or nearby service parts. Related numbers are not automatic substitutes unless the parts diagram, voltage, amperage, or function matches.
- K27-8002-D
- 27-8002-D
- LIF-K27-8002-D
- Auxiliary contact block relay
- 1 NO / 1 NC contact block
- 1NO/1NC auxiliary contact
- GH5HP contact block
- Related but different: K27-8004-D 2NO/2NC auxiliary contact block
- Related but different: primary contactor / motor starter
Technician Note
A 1 NO / 1 NC auxiliary block performs a specific control function. Replacing it with a different contact arrangement can change how the operator control circuit behaves. Always match the schematic and terminal numbers.
Before Ordering
- Confirm the existing contact block reads K27-8002-D or 27-8002-D
- Verify the contact arrangement is 1 normally open and 1 normally closed
- Check the operator model and contactor assembly diagram
- Inspect the mating contactor for wear or damage
- Have line-voltage motor-control work handled by a qualified technician
Professional Advisory
Do not jump, bypass, or rewire contact block circuits to force an operator to run. Auxiliary contacts can be part of interlock, starter, brake, or control circuits. Incorrect wiring can create unsafe door movement or equipment damage.
Questions & Answers
What does 1 NO / 1 NC mean?
It means the contact block has one normally open contact and one normally closed contact. The two contacts perform different control functions.
Is K27-8002-D the main motor contactor?
No. It is an auxiliary contact block used with a contactor or starter assembly. It is not the complete contactor.
No. K27-8004-D is a different contact arrangement. Use only the contact block shown in the wiring diagram.
Where is this contact block commonly used?
It is commonly listed for LiftMaster GH 5HP commercial door operator electrical box service work.
Why should terminal markings be checked?
Terminal markings confirm how the contact block is wired into the control circuit. Matching only the physical size is not enough.
