Liftmaster HCTDCU & HCTDCUL Overhead Gate Parts
LiftMaster HCTDCU & HCTDCUL Replacement Parts
Genuine LiftMaster replacement parts for the HCTDCU and HCTDCUL high-traffic overhead gate operators — the 24 VDC battery-backup vertical-lift operators that run the gate up a rail on a trolley and dolly. Use the exploded diagram above to find the key number for the part you need, then click any part number in the tables below.
Measure the rail before ordering. Ref 24 comes in five lengths — HCT08 (8 ft), HCT10 (10 ft), HCT12 (12 ft), HCT14 (14 ft) and HCT16 (16 ft). They are not interchangeable and the rail is supplied on its own.
This is the DC generation, not the older HCT. The HCTDCU runs a 24 VDC motor on the K1D8389-1CC board with battery backup. The AC-powered HCT uses a completely different drive and control set — only the trolley, dolly and rail hardware carry across.
Many parts are listed by Q-number. The guide gives a K-number and a Q-number for most trolley and dolly items; either will find the part.
Two trolley body kits. K1 (Q089) and K2 (Q079) are different assemblies at different points on the chain — check the diagram before ordering.
Common HCTDCU Repairs
| Symptom | Usual cause | Parts to check |
|---|---|---|
| Gate runs on mains but dies in a power cut | Backup batteries at end of life | 29-NP712 battery, K74-30762 pack, K94-37205 harness |
| Gate binds or runs rough up the rail | Trolley wheels or wheel shaft worn | K13-50141 trolley wheels, K11-50136 wheel shaft |
| Chain slack or jumping | Turn buckle out of adjustment, idler sprocket worn | K75-50132 turn buckle kit, K75-50149 idler sprocket |
| Gate stops short or overruns | APS encoder not counting | K1A6408 APS encoder, K76-34697 encoder kit |
| Motor hums but the gate does not lift | Gear reducer or motor | K32-37560-3 gear reducer, K76-38732 motor |
| Cannot release the gate in a power cut | Chain coupling release or pull ring | K07-50215 coupling release, K80-50145 pull ring |
| Gate will not reset after an obstruction | Reset switch and its product ID resistor | K94-37806 reset switch with product ID |
| Oil weeping from the gear reducer | Vent plug blocked or missing | K80-38735 vent plug kit |
Gate Operator Repair & Service Parts
| Ref | Part # | Description |
|---|---|---|
| 1 | K10-37598 | Cover, HCTDCU |
| 2 | K75-38058 | Chassis, HCTDCU — no longer available |
| 3 | K10-37595 | Battery Access Door |
| 4 | K1D8389-1CC | Main Board, DC Pad-Mounts, UL325 |
| 5 | K1D8387-1CC | Expansion Board, UL325 |
| 6 | K10-37955 | Chain Guard with Mounting Hardware |
| 7 | K80-38735 | Vent Plug Kit, HCTDCU |
| 8 | K94-36411 | Piezo Alarm |
| 9 | K52C0481 | Bridge Rectifier Kit |
| 10 | 19-41240D | Drive Chain, #41, 10 ft |
| 11 | K77-36541 | Antenna |
| 12 | K07-50215 | Chain Coupling Release, Q200 |
| 13 | K80-50142 | Lock and Keys |
| 14 | K80-50145 | Emergency Pull Ring, Q087 |
| 15 | K80-50295 | Access Door Keys, Qty 2, Q118 |
| 16 | K09-50756 | Dolly Cover, Q085 |
| 17 | K80-20078 | Plastic Plug, Q090 |
| 18 | K75-50149 | Idler Sprocket, Q091 |
| 19 | K10-50151 | Idler Sprocket Cover, Q093 |
| 20 | K11-50136 | Trolley Wheel Shaft, Q078 |
| 21 | K13-50141 | Trolley Wheels, Q083 |
| 22 | K87-E-050 | Retaining Ring Clip, Q086 |
| 23 | K15-41B17LKGH | Output Sprocket |
| 24 | HCT08 | Rail Only, 8 ft |
| 24 | HCT10 | Rail Only, 10 ft |
| 24 | HCT12 | Rail Only, 12 ft |
| 24 | HCT14 | Rail Only, 14 ft |
| 24 | HCT16 | Rail Only, 16 ft |
| 25 | 29-NP712 | Battery, 12V, 7AH, Qty 1 |
| 26 | K1A6408 | APS Encoder, 24V |
| 27 | K1D7078 | EMI Board |
| 28 | K32-37560-3 | Gear Reducer, 28:1 |
| 29 | K10-10204 | Door Mounting Bracket |
| 30 | K09-50152 | Arm Bracket, Q094 |
| 31 | K10-50154 | Head Bracket, Q096 |
| 32 | K77-50153 | Arm Bushing, Q095 |
| 33 | K10-10203 | Curved Door Arm |
| 34 | K76-38732 | Motor, 24 VDC, HCTDCU |
| 35 | K204C0211 | Transformer |
| 36 | K10-37641 | Mounting Plate |
Parts Not Shown in Diagram
| Ref | Part # | Description |
|---|---|---|
| — | K94-37205 | Battery Harness, 7AH Batteries |
| — | K94-34778 | Board to Board Wire Harness, 24V |
| — | K94-37806 | Reset Switch with Product ID |
| — | K40-38471 | UL Warning Sign |
| — | K94-36891 | Battery Wire Harness, 7AH |
Service Kits
| Ref | Part # | Description |
|---|---|---|
| K1 | K75-50147 | Trolley Body Assembly Kit, Q089 |
| K2 | K75-50137 | Trolley Body Kit, Q079 |
| K3 | K75-50138 | Trolley / Dolly Latch Kit, Q080 |
| K4 | K74-30762 | Battery Pack, 12V, 7AH, Qty 2 |
| K5 | K75-50132 | Turn Buckle Kit |
| K6 | K76-34697 | APS Encoder Kit, 24V |
| K7 | K75-50146 | Arm Assembly, Q088 |
| K8 | K75-50150 | Rubber Isolator Kit, Q092 |