VRF Troubleshooting by Symptom
You do not need an error code to work out roughly what is wrong. Find what you are seeing below and we will point you at the likely causes.
Covers Daikin VRV, Mitsubishi City Multi and LG Multi V.
What are you seeing?
Nothing is working at all
Act nowThe whole system is dead, or the outdoor unit has stopped and no zone is conditioning.
Usually power supply, a compressor that will not start, or a communication failure inside the outdoor unit. On three-phase equipment, a lost phase is common and should be left alone until an electrician checks it.
Before you call
Do not keep restarting it. If a compressor is seized or a phase is missing, repeated attempts can damage components that are still healthy.
Codes that usually explain this
One zone is out, the rest are fine
UrgentA single room or floor has no heating or cooling while everything else works normally.
Almost always communication to that unit, or a fault local to it such as a drain problem shutting it down. The outdoor unit and compressor are usually in good condition, which keeps this at the cheaper end.
Before you call
Note exactly which zones are affected before calling. One unit, one branch, or one floor each point somewhere different.
Codes that usually explain this
It runs for a while, then stops
UrgentThe system starts, runs for minutes or hours, shuts down, and later restarts on its own.
A protection device is intervening. Pressure, temperature or current has moved outside safe limits and the system stopped itself. The shutdown is protecting your compressor — the reason behind it has not gone away.
Before you call
Resist the urge to keep resetting. Each cycle puts the compressor through the same conditions that tripped protection in the first place.
Codes that usually explain this
Water is dripping from a ceiling unit
Act nowDamp patches, staining on ceiling tiles, or visible dripping below an indoor unit.
Condensate is not draining. Indoor units produce water continuously whenever they run, and it has to be pumped away. When that fails, the pan fills.
Before you call
Tell us there is visible water when you call. It changes how we prioritise the visit, because the damage risk is to your building rather than the equipment.
Codes that usually explain this
It runs but barely cools or heats
UrgentThe system is operating and air is moving, but zones never quite reach setpoint — often worst on the hottest days.
Commonly refrigerant charge, poor heat rejection at the outdoor unit, or a system asked to serve more indoor capacity than it supports. Faults that only show in extreme weather are still real faults.
Before you call
Note whether it is every zone or only some, and whether it correlates with hot weather. Both narrow the diagnosis considerably.
Codes that usually explain this
Zones are heating when they should cool
UrgentA room gets the opposite of what was asked for, or zones behave as though they are following someone else’s thermostat.
On heat recovery systems this usually means the equipment cannot route refrigerant correctly — either it has lost communication with the branch controller, or its map of which unit sits on which port is wrong.
Before you call
Ask whether any boards have been replaced or units moved. Both wipe the configuration that tells the system where everything is.
Codes that usually explain this
The outdoor unit is making an unusual noise
UrgentGrinding, rattling, screeching, or a change in the sound the unit normally makes.
Most often a fan bearing failing, or something more serious developing in the compressor. Mechanical problems are frequently audible well before they trigger a code.
Before you call
If the noise is new and loud, stop the system and call. Compressor noises in particular are worth acting on before the fault completes.
Codes that usually explain this
Energy bills have jumped with no obvious fault
Worth checkingConsumption has risen noticeably while the system appears to be running normally and nobody has complained.
Systems running inefficiently rarely announce it. Refrigerant overcharge, a dirty outdoor coil, or a lost connection to your central controls all raise consumption while everything still looks fine.
Before you call
Check whether scheduling and setbacks are still being applied. Losing central control is a common and invisible cause.
Codes that usually explain this
It has not been right since someone worked on it
Worth checkingThe system was fine, a contractor attended or the building was refitted, and it has misbehaved ever since.
This is its own category because it is so common. Replacing a control board, adding indoor units, or changing equipment all require re-commissioning. When that step is skipped, the system carries the wrong picture of itself.
Before you call
Tell us what work was done and roughly when, even if it seems unrelated. It is usually the fastest route to the answer.
Codes that usually explain this
How to find your error code
If you can get the code, everything gets faster and cheaper. It turns a diagnostic visit into a targeted one, and it often tells us what parts to bring.
You do not need to open anything or touch the equipment to do this.
- 1
Check the wired remote controller
In the affected zone. Faults usually display here first.
- 2
Check the outdoor unit display
Small digits on the control board. LG shows bare numbers here and CH-prefixed codes on remotes — same fault, two formats.
- 3
Photograph it before resetting
Detail codes and sub-codes are frequently lost the moment a fault is cleared, and they are often the most useful part.
- 4
Look it up
46 codes documented across all three platforms.
Common questions
My VRF system is not cooling. What should I check first?
Note which zones are affected and whether the outdoor unit is running. One zone failing usually means a communication or drain fault local to that unit. Everything failing points at the outdoor unit, its power supply, or the compressor.
How do I find the error code on my VRF system?
Check the wired remote controller in the affected zone first, then the outdoor unit display. Photograph what you see before resetting anything, because detail codes and sub-codes are frequently lost the moment the fault is cleared, and they are often the most useful part.
Should I keep resetting my VRF system to keep it running?
Not repeatedly. A single reset to see whether the fault returns is reasonable. Beyond that you are running equipment through the same conditions that triggered protection in the first place, and on compressor faults repeated restarts can turn one expensive repair into two.
Why does my VRF only struggle on hot days?
Because ambient heat adds to the load the system is already working against. A marginal fault such as a fouled coil or a weakening fan can be tolerable in mild weather and trip protection once temperatures rise. It is still a real fault.
One room is not cooling but the rest of the building is fine. Is that expensive?
Usually not. A single zone failing normally means a communication fault or a drain problem local to that unit, and the compressor and outdoor unit are generally in good order. Those are among the cheaper faults on a VRF system.
Can you diagnose my system without an error code?
Yes. Codes speed things up considerably, but the symptoms you can observe, which zones are affected, and what changed recently are all genuine diagnostic information. We will also talk it through with you on the phone before dispatching anyone to site.
Still not sure what you are looking at?
Describe what the system is doing and we will tell you what it probably is. Certified on Daikin, Mitsubishi and LG — and we service systems we did not install.
Next business day commercial service.