Description
Otis Elevator LL-1 Door Lock
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Product
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Otis Elevator Door Lock |
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Model
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LL-1 |
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Quality
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Original.Brand New
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Payment
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T/T. Paypal. Western Union
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Delivery
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3-5 Working Days
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Packaging
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Packed by carton
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Otis Elevator LL-1 Door Lock – The Mechanical Sentinel That Guards Every Passenger Entrance
Courtesy of Nanjing Zhuye Elevator Parts Co., Ltd.
Courtesy of Nanjing Zhuye Elevator Parts Co., Ltd.
Every elevator journey begins with a click — the sound of the LL-1 door lock engaging. This robust, mechanically-positive lock ensures that car doors remain securely closed until the elevator is perfectly level and ready to open. Originally designed by Otis for Gen2-R2®, SkyRise® and Chinese super-MRL systems, the LL-1 lock is now the universal retrofit for any controller demanding SIL-2 safety integrity. Nanjing Zhuye Elevator Parts keeps factory-sealed LL-1 locks in anti-static stock for next-day despatch. Below we explain what the lock does, how to install it in under 15 minutes, and the replacement cycle that prevents expensive “door lock fault” call-backs.
1. What LL-1 Door Lock Really Is
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Type: mechanically-positive, SIL-2 certified, centre-opening passenger doors
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Material: zinc-nickel plated steel, -25 °C to +70 °C, IP54
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Contacts: 2 × NO + 1 × NC, gold-plated, 4 A 250 VAC, >1 million cycles
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Force: <15 N release, >30 N holding, ±1 mm repeat accuracy
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Fixings: M6 stainless screws, captive washers, Loctite pre-applied
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Pack unit: 1 lock + 2 keys + 4 screws + 1 × 2 mm Allen key
The lock engages when the car is within ±5 mm of floor level and releases only when the controller issues a 24 VDC “door open” command.
2. Where It Is Used
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Otis Gen2-R2®, SkyRise® 1.0–4.0 m s⁻¹
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Thyssen TCM-MC3 retrofit kits
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Chinese super-MRL controllers with 24 VDC safety chains
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Suitable for centre-opening doors 800–1,400 mm clear width
3. Installation – 15-Minute Retrofit
Safety: place lift on inspection, lock main breaker, tag out, prop door to 50 % open.
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Remove old lock — undo 2 M6 screws; unplug 6-way Molex.
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Inspect striker — if worn >0.5 mm, replace striker (Nanjing Zhuye part ST-LL1).
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Insert LL-1 — push into 22 mm hole until snap-ring clicks; earth strap to PE.
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Connect plug — brown +24 V, blue 0 V, white NO, grey NC, green earth.
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Insert key — turn to ON; green LED must light and controller must log “Lock OK”.
No laptop is required; the lock is pre-wired and keyed at the factory.
4. Daily Operation – What the Lock Actually Does
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Engages when car is within ±5 mm of floor level; releases only on 24 VDC command
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Auto-detects key removal; drops safety chain within 50 ms
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LED indicator: green = locked, red = unlocked, off = no power
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Built-in self-test every 24 h — if contact resistance >100 mΩ, “Lock Fault” is logged
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IP54 gasket resists car-wash water jets; UV-stabilised housing prevents yellowing
5. Replacement Cycle & Preventive Maintenance
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High-traffic metro (>1,500 cycles day⁻¹) – inspect every 6 months, replace lock every 3 years
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Shopping mall (600–1,000 cycles day⁻¹) – inspect annually, replace every 5 years
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Low-rise office (≤400 cycles day⁻¹) – inspect every 18 months, replace every 7 years
Replace immediately if:
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Key cannot be removed in OFF position
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Contact resistance >100 mΩ at 1 A
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LED off with 24 V present
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Housing cracked or key code worn illegible
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Water ingress (fog inside lens)
6. Extending Life – 3 Pro Tips
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Keep key clean; grit in barrel wears pins and increases insertion force
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Torque M12 nut to 1.5 N·m; over-tightening cracks the housing
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Close cabinet door; condensation on contacts causes oxidation
7. Why Buy LL-1 from Nanjing Zhuye Elevator Parts?
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Factory-new, not refurbished; passes 1,000,000-cycle insertion test at 60 °C
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Key code pre-cut; matches Otis original pattern, no re-pinning required
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Anti-static foam box + silica gel — safe for air freight
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Dual stock: 520 pcs Nanjing, 180 pcs Dubai — next-day delivery to 65 countries
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Bundle kit: lock + 2 keys + 6-way plug + 22 mm hole-saw — 5 % discount
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24 months warranty against mechanical wear or contact failure
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7×24 WhatsApp/WeChat video support; average response 10 minutes
Conclusion
The LL-1 door lock is the unseen gatekeeper that authorises every elevator start. A single worn contact can shut down an entire shopping mall. Stock a spare from Nanjing Zhuye on every service truck, swap it on schedule, and replace “door lock fault” panic with a five-minute planned fix — one safe, authorised start at a time.
