LG Electronics
MultiV VRF and THERMA V Heat Pump — LGAP Modbus to KNX Integration
LG Electronics (Seoul, South Korea, founded 1958) manufactures the MultiV VRF range — one of Europe's most widely installed commercial air conditioning systems. MultiV 5 (R410A/R32, up to 64 indoor units per outdoor, COP 3.9) integrates with KNX via the LGAP (LG Air conditioner Protocol) Modbus RS-485 bus, converted by gateways such as Intesis to KNX group addresses. The THERMA V heat pump range (R32, 5–29kW) adds heat pump functionality with Modbus BMS integration for hotel and commercial building projects.
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MultiV 5 architecture: LG MultiV 5 outdoor units (3-phase inverter compressor, R410A or R32, capacity 8–90kW per outdoor, modular frame connection for larger systems, up to 64 indoor units per outdoor). Indoor unit types: 4-way cassette (LTN series), ducted concealed (LDN series), wall console (LS series), floor-standing (LB series). Communication: F-BUS (LG proprietary 2-wire RS-485, 9600 baud) connects all indoor and outdoor units. LGAP protocol runs on F-BUS — each indoor unit is addressed 0–63 (set via DIP switch or remote controller menu). The LG PQNFB17C0 BMS interface unit bridges F-BUS LGAP to an RS-485 port for external Modbus communication. LGAP Modbus integration: LG PQNFB17C0 BMS interface → RS-485 A/B/GND to Intesis INMBSLAN0600000 Modbus TCP gateway. Register map per indoor unit (base address = unit_address × 100): Holding 0 = On/Off (0/1), Holding 1 = Mode (0=Cool, 1=Dehumidify, 2=Fan, 3=Auto, 4=Heat), Holding 2 = Setpoint (integer, 0.5°C resolution, value 32=16°C), Holding 3 = Fan speed (0=Auto, 1–3=Low/Med/High), Holding 5 = Room temperature feedback (integer, 1°C resolution), Holding 11 = Fault code (0=OK, non-zero per LG fault table). Intesis INMBSLAN0600000 → KNX via Intesis IN701KNX Modbus-to-KNX gateway → KNX group addresses for each indoor unit control and status. THERMA V heat pump: LG THERMA V R32 heat pump (5–29kW, ErP A+++ rated, built-in EVI compressor for -25°C operation). BMS integration via LG HVAC Central Controller (AC Smart Premium with Modbus RS-485 option) — same LGAP protocol. KNX integration: LGAP registers for THERMA V include DHW temperature setpoint (Holding 10), DHW mode (Holding 12), outdoor temperature (read-only, Holding 20). For heat pump SG Ready: LG THERMA V has a dedicated SG Ready 2-wire input terminal — connect to KNX binary output relay for PV surplus signalling. Installation and commissioning: LG MultiV commissioning requires LG-certified engineer (compressor test, address assignment, refrigerant charge). For KNX integration: LGAP gateway commissioning (RS-485 wiring, baud rate 9600, termination resistor at furthest device), Intesis MAPS signal table configuration (48 units × 5 signals = 240 Modbus points → 240 KNX GAs), ETS6 group address download. Verify: ETS6 Group Monitor polls all room temperature feedback GAs — values received within 60 seconds confirms successful LGAP communication chain.
LGAP Modbus RS-485 integration via LG BMS interface and Intesis/MDT gateway — per-unit on/off, mode, setpoint, room temperature, and fault status mapped to KNX group addresses for hotel and commercial BMS control.
Used in these project types
LG Electronics products
Key components we install
LG MultiV 5 outdoor unit (10kW)
R410A 3-phase inverter, up to 12 indoor units, F-BUS LGAP, PQNFB17C0 BMS interface port
LG BMS interface unit
F-BUS to RS-485 LGAP bridge for Modbus integration with Intesis or MDT KNX/Modbus gateway
LG 4-way cassette indoor unit (3.5kW)
Ceiling cassette, LGAP F-BUS address 0–63, compatible with PQNFB17C0 BMS integration
LG THERMA V R32 heat pump (9kW)
R32 air-water heat pump with Modbus BMS, SG Ready input, -25°C operation (EVI)
LG ThinQ commercial controller
Central management for up to 64 LG units, touch display, individual room or group control
LG Electronics FAQ
What is the difference between LGAP and LG Multi protocol?
LGAP (LG Air conditioner Protocol) is the RS-485 protocol used by LG Commercial (MultiV, PRHR series) for BMS integration via the PQNFB17C0 BMS interface. LG Multi is the simpler residential VRF range — it uses the same F-BUS but a simplified Modbus register set. Intesis gateways support both LGAP (commercial) and LG Multi (residential) — specify the correct gateway model for each range.
How many LG indoor units can one Intesis gateway handle?
The Intesis INMBSLAN0600000 Modbus TCP gateway communicates with the LG PQNFB17C0 BMS interface which can address up to 64 indoor units per LGAP bus. One PQNFB17C0 can monitor all 64 units. For larger buildings with multiple outdoor units: install one PQNFB17C0 per outdoor unit (up to 64 units each), and one Intesis gateway per PQNFB17C0 (or configure multiple Modbus TCP targets in one gateway if supported).
Can LG THERMA V and MultiV be integrated into the same KNX system?
Yes — both use the same LGAP Modbus integration chain (PQNFB17C0 → RS-485 → Intesis → KNX). Assign different KNX GA ranges to THERMA V (e.g., main group 8) and MultiV (main group 7) for clarity. The KNX visualisation (Gira X1 or IP-Symcon) shows HVAC and heat pump together on the same floor plan.
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