Brands with a code list
Daikin fan coil service
Alarko Carrier fan coil service
Carrier fan coil service
Aermec fan coil service
Galletti fan coil service
Sabiana fan coil service
McQuay fan coil serviceDaikin fan coil error codes
FWT wall-mounted, FWC cassette, FWF and FWG series (wired controller display)
When an abnormality occurs, the wired controller shows the error code by flashing it.
| Code / indication | Meaning | What to do |
|---|---|---|
| E1 | Room (ambient) temperature sensor fault: open or short circuit | Check the sensor socket and cable; replace the sensor if necessary. |
| E2 | Water pipe / coil temperature sensor fault | The sensor connection and resistance are measured; the sensor is replaced if necessary. |
| E4 | Water temperature not suitable (insufficient) | The chiller or boiler outlet water, valve and circulation are checked. |
| E5 | Incorrect water temperature | The water supply, 3-way valve and heating/cooling mode selection are checked. |
| E6 | Drain (condensate) pump fault (cassette) | The drain line and float are cleaned and the pump is tested. |
| E8 | Hardware fault: short-circuited button on the board | The display or control board needs replacing. |
| E9 | No feedback from the indoor fan motor (FWT) | The fan motor connector is checked; the motor or board is replaced. |
European series (FWV, FWL, FWM, FWZ, FWR, FWS, FWB, FWD) – FWEC control board
This series has no numbered error codes. If the water temperature does not suit the mode (e.g. lukewarm water in cooling), the mode symbol on the controller flashes. Fix: check the chiller/boiler and the water temperature.
Daikin fan coil service page →
Carrier fan coil error codes
Carrier 42GW cassette – HDB control board
The red LED on the board flashes as many times as the fault number (0.5 s on / 0.5 s off, followed by a 5 s pause).
| Code / indication | Meaning | What to do |
|---|---|---|
| 2 flashes | Air temperature sensor fault | The sensor and socket are checked and replaced if necessary. |
| 3 flashes | Water (changeover) sensor fault | The water sensor connection and its position on the pipe are checked. |
| 4 flashes | Cold draught thermistor fault | The thermistor is checked or replaced. |
| 5 flashes | Condensate pump fault | The drain line and float are cleaned and the pump is checked. |
| 6 flashes | Electric heater configuration error | Board settings (DIP switches / parameters) are corrected. |
| 7 flashes | Board memory (EEPROM) error | The control board needs replacing. |
| 8 flashes | Chilled beam configuration error | The configuration is corrected. |
Carrier 42N series – electronic control
Faults are indicated by the colour of the LEDs on the board.
| Code / indication | Meaning | What to do |
|---|---|---|
| Red LED flashing | Sensor fault: room sensor or water temperature sensor faulty or short-circuited | The sensors are measured and the faulty one is replaced. |
| Yellow LED flashing | Configuration error: central changeover signals active at the same time | Wiring and settings are corrected. |
Carrier 42TPM
If there is more than one fault, the codes are shown in sequence.
| Code / indication | Meaning | What to do |
|---|---|---|
| E1 | Room sensor fault | The sensor is checked or replaced. |
| E2 | Coil sensor fault | The sensor is checked or replaced. |
Carrier fan coil service page →
Aermec fan coil error codes
VMF system (FCZ, FCZI, FCXI, VED, Omnia) – VMF-E4X controller display
| Code / indication | Meaning | What to do |
|---|---|---|
| AL 1 | No communication between the controller and the fan coil thermostat (E0/E1) | The communication cable, polarity and power supply are checked. |
| AL 2 | Inverter (EC fan) board fault | The LEDs on the inverter board in the fan coil are checked. |
| AL 3 | Room sensor in the controller faulty | The system switches to the sensor on the fan coil; the controller is serviced. |
FCXI inverter board
The board has alarm and power LEDs. Alarm types: high temperature, overvoltage, undervoltage, overcurrent, overload, safety. If an alarm lasts longer than 1.5 minutes it becomes permanent; it is reset by switching the power off and on again.
Aermec fan coil service page →
Galletti fan coil error codes
EVO / EVO-2-TOUCH controller
Instead of numbered codes, "probe alarm" (air or water sensor) and "no RS485 communication" warnings are shown. Fix: check the probe wiring and polarity, the board power supply (STATUS LED) and the RS485 line.
Galletti fan coil service page →
Sabiana fan coil error codes
Carisma (ECM) – status warnings
This series uses LED warnings instead of numbered codes: T1 sensor fault, T3 sensor above 70 °C, window contact open, pump alarm. If there is more than one event, two LEDs flash together.
Sabiana fan coil service page →
McQuay fan coil error codes
McQuay MFU-C – AC2800 electronic controller
Faults are indicated by the number of LED flashes.
| Code / indication | Meaning | What to do |
|---|---|---|
| 5 flashes | Fan coil mode and water temperature do not match (e.g. cold water in heating mode) | The mode selection and chiller/boiler status are checked. |
| 7 flashes | Ambient temperature sensor malfunctioning | The sensor is checked or replaced. |
| 8 flashes | Water temperature sensor malfunctioning | The sensor is checked or replaced. |
McQuay fan coil service page →
Thermostat alerts (Siemens RDF series)
| Indication | Meaning | What to do |
|---|---|---|
| AL1 | External fault input X1 active (e.g. condensate alarm) | The device connected to input X1 is checked. |
| AL2 | External fault input X2 active | The device connected to input X2 is checked. |
| FIL | Filter cleaning reminder | The filter is cleaned and the alert reset. |
| Dew (condensation) symbol | Condensation detected in the room, cooling stopped | Humidity and water temperature are checked. |
Diagnosis on fan coils without error codes
Many fan coils, such as Aldağ, Üntes, Form and Airfel, run with a 3-speed motor and a simple thermostat and have no error codes. Diagnosis is based on symptoms and measurements:
| Symptom | Possible cause | Details |
|---|---|---|
| Leaking water | Blocked drain, full/cracked drain pan, sweating valve | Solution |
| Not cooling / not heating | Stuck motorized valve, air in the coil, dirty filter | Solution |
| Fan not running | Capacitor, motor, speed control | Solution |
| Room always cold/hot | Valve stuck open or closed | Solution |
| Controller not responding | Thermostat, sensor, wiring | Solution |
What the code groups generally mean
Sensor codes
Indicate that the room, water or coil sensor is open or short-circuited. Usually the sensor or its socket is replaced.
Water temperature codes
Indicate that the incoming water does not suit the selected mode. The problem is often in the chiller, boiler or valve.
Drain / pump codes
A float or pump alarm on cassette and concealed ceiling units. The drain pan and drain line are checked.
Communication and board codes
No communication between the controller and the board, or a faulty board memory. Wiring and the board are checked.
Sources: manufacturers' user and service manuals; the sources for each brand are listed in its own section and on the brand page.
Frequently asked questions
What does a fan coil E1 error mean?
On units such as Daikin and Carrier 42TPM, E1 indicates a room temperature sensor fault. The sensor or its socket is checked and replaced if necessary. The meaning of a code can vary by controller.
How is a fan coil condensate pump error fixed?
The drain pan and drain line are cleaned, the float is checked to make sure it moves freely and the pump is tested. If the pump has failed, it is replaced.
My fan coil shows no code but does not work. What should I do?
First check the breaker and the controller. If the problem persists, send us the symptom and the unit's rating plate and we will diagnose it with measurements.