- Heat pumps
- Air-to-water heat pump
CH14
LG CH14 on a Therma V heat pump: flow switch problem
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
On LG Therma V monobloc units, CH14 means the flow switch is open while the internal water pump runs. Check the front pressure gauge and that the shut-off valves are open; LG says to call service when a code appears.
Safety first
Stop and check this first
- LG says not to install, remove, inspect or repair the unit yourself, because of the risk of fire, electric shock or explosion, and that the unit uses flammable refrigerant. If there is a burning smell or loud noise, stop the unit, turn the breaker off and call service.
Safe checks you can perform
- Front pressure gauge
- Inlet and outlet shut-off valves
- Purging, strainer, bypass and pump setting
Leave these tasks to a qualified professional
- Do not attempt this professional task: Flow switch test
- Do not attempt this professional task: Hydraulic check before the switch
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Flow switch test
What they doIf flow is correct, the technician checks that the switch closes with the pump running and inspects its connection.
They must show youthe switch state with the pump off and running.
In writingwhether it was replaced, its part number and the test without CH14.
Hydraulic check before the switch
What they doThe technician purges, cleans the strainer, sets the pump and bypass valve per LG's manual and only then tests the switch.
They must show youpressure between 2.0 and 2.5 bar, the clean strainer and the pump off Minimum.
In writingwhat they found and what they adjusted.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Front pressure gauge
- Who:
- you, reading only.
- How:
- read the pressure gauge on the front of the unit.
- Result that matters:
- LG gives 2.0 to 2.5 bar in normal state, never above 3.0 bar, and says to recharge below 0.3 bar.
- If it is well below 2.0 bar:
- water is missing and air is likely; ask the installer to refill and purge.
- If it is between 2.0 and 2.5 bar:
- lack of water is ruled out; air, bypass, strainer or the switch remain.
- Evidence to keep:
- a photo of the gauge with the date.
Evidence: LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607 · LG air to water heat pump owner's manual MFL68026705
Inlet and outlet shut-off valves
- Who:
- you, without opening the unit.
- How:
- check that the two shut-off valves, at the end of the unit's water inlet and outlet pipes, are open.
- Result that matters:
- LG requires both to be open before operation.
- If one was closed:
- open it and tell service; nothing more is needed if CH14 does not return.
- If both were open:
- the valves are ruled out; air, strainer, bypass or the switch remain.
- Evidence to keep:
- a note of which valve was closed.
Evidence: LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607 · LG air to water heat pump owner's manual MFL68026705
Purging, strainer, bypass and pump setting
- Who:
- the installer or LG authorised service.
- How:
- they purge air until water spurts from the air purge, close the valves and clean the strainer, check the bypass valve and check the pump is not set to Minimum.
- Result that matters:
- flow restored and the switch closed with the pump running, which is the normal condition per LG.
- If CH14 does not return after purging, cleaning or adjusting:
- a hydraulic cause is confirmed.
- If everything is correct and the switch stays open with the pump running:
- the flow switch or its connection is the suspect.
- Evidence to keep:
- a job sheet with the final pressure, pump setting and strainer condition.
LG says to turn off the power before any troubleshooting. Opening the unit and working near flammable refrigerant is for authorised personnel only.
Evidence: LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607 · LG air to water heat pump owner's manual MFL68026705
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Heat pumps
- Brand
- LG
- Product type
- Air-to-water heat pump
Known code variants
- LG heat pump CH14
- LG Therma V CH14
- Therma V 14
What it means
LG defines CH14 as a flow switch problem: it is open while the internal water pump runs, when it should be closed. LG links it to insufficient flow: pump capacity set to Minimum, a missing or badly adjusted bypass valve, incomplete air purging, closed shut-off valves, a strainer full of particles or pipes narrowed by lime. The code does not say whether flow is really low or the switch itself failed.
Warnings and stop conditions
- Highsource verified
LG says not to install, remove, inspect or repair the unit yourself, because of the risk of fire, electric shock or explosion, and that the unit uses flammable refrigerant. If there is a burning smell or loud noise, stop the unit, turn the breaker off and call service.
Evidence: LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607 · LG air to water heat pump owner's manual MFL68026705
Symptoms and causes
Probable causes · in order
- Air in the circuitCommon
LG says that if purging is not sufficient CH14 can occur, and that removing air takes time. It fits in the first weeks or after refilling.
Evidence: LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607 · LG air to water heat pump owner's manual MFL68026705
- Pump on Minimum or no bypassPossible
LG says not to leave the pump on Minimum and to fit an adjusted bypass valve to secure flow. It shows in settings and installation, not in the code.
Evidence: LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607 · LG air to water heat pump owner's manual MFL68026705
- Dirty strainer, closed valves or limePossible
A strainer with particles, a closed shut-off valve or pipes narrowed by lime reduce flow. LG says to clean the strainer with the shut-off valves closed.
Evidence: LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607 · LG air to water heat pump owner's manual MFL68026705
- Flow switchLess common
If flow is correct and the switch stays open with the pump running, the fault is in the switch or its connection.
Evidence: LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607 · LG air to water heat pump owner's manual MFL68026705
Virtual technician
Does CH14 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
LG Therma V R32 Monobloc air to water heat pump installation manual MFL68026607
LG Electronics · 2026 · manual
- 2
LG air to water heat pump owner's manual MFL68026705
LG Electronics · 2026 · manual
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