LG ThermaV R290 — Home Assistant Integration

Archived — this is the version for Home Assistant 2026.8 and older. Development continues at cjungde/ha-lg-thermav-modbus.

The successor requires Home Assistant 2026.9, where it takes a unit on the modbus component's shared connection instead of running a pymodbus client of its own. That matters on RS485: integrations reaching one gateway over separate sockets interleave their requests, and replies come back on transaction ids the other client is not expecting. Sharing the connection serializes them behind one lock and ends that.

The two cannot be one release — the successor cannot run on 2026.8, and dropping every user on an older core to say so would be worse than a split.

Moving across is a straight swap. Both use the integration domain lg_thermav_r290, so entity ids, history and long-term statistics survive it and the config entry is read as it stands. Uninstall this one first, then install the successor and restart — do not run both, they claim the same directory.

This repository stays readable and installable. It receives no further changes.

HACS custom integration for the LG ThermaV R290 heat pump via Modbus TCP or RTU.

Replaces a hand-crafted YAML Modbus configuration with native HA entities: sensors, binary sensors, switches, buttons, number inputs, and select dropdowns — all updated on every poll cycle without requiring template sensors or automations.

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Features

• Sensors — temperatures (inlet, outlet, DHW, outdoor, refrigerant circuit), flow rate, pressures, compressor speed, error code, operation mode, control method, energy state
• Computed thermal power sensors — total / heating circuit / DHW, calculated from flow rate and ΔT each poll cycle (Q = flow/60 × ΔT × 4186 W)
• Binary sensors — compressor, pumps, DHW heating, defrost, backup heater stages, fault, silent mode, cooling, emergency modes, energy state slots 0–8
• Switches — main power, DHW, silent mode, emergency stop
• Buttons — start DHW disinfection (momentary trigger coil)
• Number inputs — flow temperature setpoints (circuit 1, circuit 2), DHW target temperature, heating curve shift values (circuit 1, circuit 2)
• Select inputs — operation mode (Heating / Cooling / Auto), control method (outlet temp / inlet temp / room air)
• Supports Modbus TCP, Modbus TCP-RTU, and Modbus RTU (serial)
• Configurable poll interval (default 30 s), reconfigurable without restart

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Installation via HACS

1. In HACS → Integrations → ⋮ → Custom repositories, add https://github.com/cjungde/ha-lg-thermav-r290 with category Integration.
2. Install "LG ThermaV R290".
3. Restart Home Assistant.
4. Settings → Devices & Services → Add Integration → search "LG ThermaV R290".

Manual installation

Copy the custom_components/lg_thermav_r290/ folder into your HA custom_components/ directory and restart.

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Configuration

The config flow asks for connection type first, then connection-specific parameters:

Parameter	Default	Notes
Connection type	—	TCP / TCP-RTU / RTU
Host / IP	—	TCP only
Port	502	TCP only
Serial port	—	RTU only (e.g. /dev/ttyUSB0)
Baudrate	9600	RTU only
Parity	N	RTU only
Stop bits	1	RTU only
Slave ID	1	1–247
Poll interval	30 s	Adjustable in Options

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Entities

Sensors

Entity	Description	Unit
sensor.lg_thermav_r290_inlet_temperature	Inlet water temperature	°C
sensor.lg_thermav_r290_outlet_temperature	Outlet water temperature	°C
sensor.lg_thermav_r290_dhw_temperature	DHW tank temperature	°C
sensor.lg_thermav_r290_outdoor_temperature	Outdoor air temperature	°C
sensor.lg_thermav_r290_backup_heater_outlet_temperature	Backup heater outlet temp	°C
sensor.lg_thermav_r290_flow_temperature_circuit_2	Flow temperature circuit 2	°C
sensor.lg_thermav_r290_flow_rate	Water flow rate	l/min
sensor.lg_thermav_r290_water_pressure	Water pressure	bar
sensor.lg_thermav_r290_high_pressure_condenser	High pressure (condenser)	bar
sensor.lg_thermav_r290_low_pressure_evaporator	Low pressure (evaporator)	bar
sensor.lg_thermav_r290_compressor_speed	Compressor speed	rpm
sensor.lg_thermav_r290_error_code	Error code	—
sensor.lg_thermav_r290_thermal_power_total	Total thermal power output	W
sensor.lg_thermav_r290_thermal_power_heating_circuit	Heating circuit thermal power	W
sensor.lg_thermav_r290_thermal_power_dhw	DHW thermal power	W
sensor.lg_thermav_r290_operation_mode	Operation mode (label)	—
sensor.lg_thermav_r290_control_method	Control method (label)	—
sensor.lg_thermav_r290_energy_state	Energy state (label)	—

Binary sensors

Entity	Description
binary_sensor.lg_thermav_r290_compressor	Compressor running
binary_sensor.lg_thermav_r290_water_pump	Water pump running
binary_sensor.lg_thermav_r290_external_water_pump	External water pump
binary_sensor.lg_thermav_r290_dhw_heating	DHW heating active
binary_sensor.lg_thermav_r290_defrost	Defrost active
binary_sensor.lg_thermav_r290_dhw_disinfection	DHW disinfection
binary_sensor.lg_thermav_r290_backup_heater_step_1	Backup heater step 1
binary_sensor.lg_thermav_r290_backup_heater_step_2	Backup heater step 2
binary_sensor.lg_thermav_r290_dhw_boost_heater	DHW boost heater
binary_sensor.lg_thermav_r290_fault	Fault active
binary_sensor.lg_thermav_r290_silent_mode	Silent mode
binary_sensor.lg_thermav_r290_cooling_active	Cooling active
binary_sensor.lg_thermav_r290_water_flow	Water flow present (see note below)
binary_sensor.lg_thermav_r290_energy_state_normal_operation	Energy state: normal (value 2)
…	Energy states 0–8 as individual binary sensors

Note on discrete input 10001 (water flow). The LG manual documents this bit as 0 = flow rate OK / 1 = flow rate too low. On the R290 monoblock it behaves the other way round: the bit is set while water is flowing. Measured on 2026-08-18 — di[0] = 0 at 5.0 LPM with the pump off, di[0] = 1 at 15.3 and 29.5 LPM with the pump running, with di[0] and di[1] (pump) identical in every sample of the same poll. A read offset is ruled out, since di[3] (compressor) and di[5] (DHW heating) stay correctly aligned.

The entity is therefore exposed as binary_sensor.lg_thermav_r290_water_flow with device class running. Up to and including v0.x it was named ..._water_flow_insufficient with device class problem, which raised a false problem alert on every pump run. After updating, the old entity remains in the registry as unavailable and can be removed manually.

Switches

Entity	Modbus coil
switch.lg_thermav_r290_heat_pump	Coil 0
switch.lg_thermav_r290_dhw	Coil 1
switch.lg_thermav_r290_silent_mode	Coil 2
switch.lg_thermav_r290_emergency_stop	Coil 4

Buttons

Coil 3 is a momentary trigger, not a state switch. The manual specifies it as 0: hold status / 1: start operation — the unit clears the coil by itself after the write, so reading it back is never a confirmation. Use the binary sensor to see whether the operation actually started.

Entity	Modbus coil	Status entity
button.lg_thermav_r290_start_disinfection	Coil 3 (trigger)	binary_sensor.lg_thermav_r290_dhw_disinfection (discrete 6)

Breaking change in 0.0.11: this replaces switch.lg_thermav_r290_disinfection_mode, which modelled a trigger coil as a switch and therefore always read back off, even when the write succeeded. After updating, the old switch remains in the registry as unavailable and can be removed manually. Note that the trigger only has an effect if disinfection is enabled on the unit itself (installer menu → DHW → disinfection active; factory default is off).

Number inputs

Entity	Range	Holding register
number.lg_thermav_r290_target_temperature_circuit_1_radiators	30–50 °C	2 (×0.1)
number.lg_thermav_r290_target_temperature_circuit_2_underfloor	20–40 °C	5 (×0.1)
number.lg_thermav_r290_dhw_target_temperature	35–60 °C	8 (×0.1)
number.lg_thermav_r290_setpoint_shift_circuit_1	−5…+5 K	4 (signed)
number.lg_thermav_r290_setpoint_shift_circuit_2	−5…+5 K	7 (signed)

Select inputs

Entity	Options	Holding register
select.lg_thermav_r290_operation_mode	Heating / Cooling / Auto	0
select.lg_thermav_r290_control_method	Outlet / Inlet Water Temp Control / Room Air Control	1

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Modbus register map (summary)

FC	Address range	Content
FC04 (input)	0–24	Temperatures, flow, pressures, compressor speed, error code
FC04 (input)	9997–9998	Product info, device group
FC03 (holding)	0–9	Operation mode, control method, setpoints, shift values, energy state
FC01 (coils)	0–4	Main switch, DHW, silent mode, disinfection trigger, emergency stop
FC02 (discrete)	0–16	Status bits (compressor, pumps, defrost, faults, …)

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Notes

• Thermal power formula: Q [W] = (flow_rate [l/min] / 60) × (outlet_temp − inlet_temp) [K] × 4186 [J/(l·K)]
• Heating circuit / DHW split is based on the di_dhw_heating discrete input; when DHW is active the full flow is attributed to DHW and the heating circuit sensor reports 0, and vice versa.
• Shift values (holding regs 4, 7) are stored as two's-complement uint16; values ≥ 32768 are interpreted as negative.
• Tested on LG ThermaV R290 9 kW via Modbus TCP, slave ID 33.

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License

MIT