LG heat pump error codes
17 codes that LG Electronics publishes for its heat pumps, each with what it means, the likely cause, what you can safely check and when to call an installer. Tap your code:
Heat pump: do only the checks the maker gives the owner for that code — read the water pressure on the controller, keep the outdoor unit clear of leaves and snow, switch the power off and on where the maker says to. Keep the casing on: refrigerant, wiring and the water circuit’s parts are not owner work. Anything else is for the heat-pump installer or the maker’s service engineer: in the UK and EU only an F-gas certified technician may open the refrigerant circuit. Codes that need one are marked Installer.
Read this first
LG Therma V air-to-water heat pumps report a fault in a pop-up window on the remote controller’s screen, with an error code. LG’s owner’s manual for the R290 Therma V monobloc units (HM071HF to HM163HF, UB40 and UB60) prints the codes as numbers — 01, 14, 231 — and names the water-tank sensor fault CH08 in its notes, so a screen showing CH14 means code 14 below. LG’s instruction to the owner is the same for every code: note it down and tell your installer or an authorised LG service centre. What the manual adds, and this page keeps, is how bad each code is: whether the heat pump stops, and whether the electric backup heater can keep the house warm meanwhile (emergency operation). Models differ: your model’s manual is the authority.
CH14 Water flow rate problem
- What it means
- The flow switch found too little water flowing while the pump was running. LG classes it as a critical trouble: the system stops and can be resumed only after a certified professional has checked it, and neither the heat pump nor the backup heater runs in the meantime.
- Likely cause
- Low water flow during pump operation; the owner’s manual names the detection, not the cause.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer and give them the code. LG’s yearly maintenance list for the technician includes checking that the water pressure is not too high or too low.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH15 Water pipe overheated
- What it means
- The temperature of the water pipe went above a set limit. A critical trouble: the system stops until a certified professional has checked it, with no emergency operation.
- Likely cause
- Water in the pipe hotter than the unit allows; the manual gives no further cause.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH20 Electric heater overheated
- What it means
- The fuse of the electric (backup) heater has blown because it overheated. A critical trouble: the system stops and waits for a certified professional; no emergency operation, since the heater itself is the fault.
- Likely cause
- Overheating of the electric heater.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer: the heater fuse and the reason it overheated are theirs to deal with.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH232 Flow sensor damaged
- What it means
- The indoor unit’s flow sensor is damaged. A critical trouble: the system stops until a certified professional has checked it.
- Likely cause
- A damaged flow sensor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH16 Several water sensors at once
- What it means
- Codes 17, 18 and 19 (the water-inlet, water-outlet and backup-heater outlet sensors) occurred at the same time. Unlike each of them alone, LG classes this as a critical trouble: the system stops until a certified professional has checked it.
- Likely cause
- Three water temperature sensors reporting faults together.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH03 Remote controller not communicating
- What it means
- The wired remote controller and the indoor unit cannot communicate. A critical trouble in LG’s table: the system stops until it has been checked.
- Likely cause
- No communication between the wired remote controller and the indoor unit.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH09 Circuit board memory (EEPROM) fault
- What it means
- The optional EEPROM memory chip is loose in, or disconnected from, the indoor unit’s main circuit board. A critical trouble: the system stops until it has been checked.
- Likely cause
- A loose or disconnected EEPROM on the main board.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer: this is inside the indoor unit.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH05 Indoor and outdoor boards not communicating
- What it means
- There is no communication between the indoor main circuit board and the outdoor (cycle) main board. A heavy trouble: the heat pump cycle cannot run, but if an electric backup heater is fitted, emergency operation can keep heating going (heating only, no cooling).
- Likely cause
- Lost communication between the indoor and outdoor main boards.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer. If emergency operation is running, LG says it raises electricity use and should not run for long.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH02 CH06 Refrigerant pipe sensor
- What it means
- A refrigerant pipe temperature sensor of the indoor unit is open or short-circuited: CH02 on the inlet side, CH06 on the outlet side. A heavy trouble: the heat pump cycle stops, and an electric backup heater, if fitted, can heat the house in emergency operation (heating only).
- Likely cause
- An open or shorted refrigerant temperature sensor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH17 CH18 CH19 Water temperature sensor
- What it means
- A water temperature sensor of the indoor unit is open or short-circuited: CH17 the water inlet, CH18 the water outlet, CH19 the electric backup heater’s water outlet. A slight trouble: both the heat pump and the backup heater can keep running in emergency operation. If two or three of them fail together, the code becomes CH16.
- Likely cause
- An open or shorted water temperature sensor; LG says slight troubles are in most cases sensor problems.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer and give them the exact code.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH01 Remote room air sensor
- What it means
- The remote room air temperature sensor of the indoor main board is open or short-circuited. A slight trouble: the heat pump and backup heater can both keep running in emergency operation.
- Likely cause
- An open or shorted room air sensor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH231 Water pressure sensor damaged
- What it means
- The indoor unit’s water pressure sensor is damaged — LG’s description is of the sensor itself. A slight trouble: emergency operation is possible.
- Likely cause
- A damaged water pressure sensor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
CH08 CH13 Hot-water tank or solar sensor
- What it means
- An optional-function sensor is open or short-circuited: CH08 the domestic hot-water tank sensor, CH13 the solar pipe sensor. LG calls it an option trouble: the system keeps running without the function that has the fault — with CH08, LG’s own example, hot water heating is not available.
- Likely cause
- An open or shorted tank or solar sensor.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Call your installer; heating carries on meanwhile.
Source: LG Electronics, Owner’s manual, LG air-to-water heat pump (Therma V R290 monobloc) HM071/091/093/121/123/141/143/161/163HF UB40/UB60 (MFL68680917, Rev.03, 2025): Emergency operation, Error code list Checked 2026-10-13.
A code that is not listed here
This owner’s manual lists only the codes of the indoor unit’s main circuit board, 01 to 20, 231 and 232. Codes such as CH10, CH24, CH26, CH35, CH38 and CH67, which people also search, are not in it: they come from other parts of the system, and their meaning is in LG’s installation or service documents for your model. Emergency operation is not restarted by itself after a power cut — LG says you must restart the product — and LG warns that it uses more electricity and should not be run for long periods.
We list only codes the source below states. If your code is not here, it may belong to a model the source does not cover: your model’s manual is the authority.
Related pages
Source
Every code on this page comes from this page, published by LG Electronics and read on the date shown. Meanings are written in our own words; nothing is taken from other makes, other models or third-party code sites.