Vent-Axia and Duco Fault Codes: Full List by Model
Every fault code, warning and status light for Vent-Axia and Duco ventilation units, by manufacturer and model, with what each one means and what to check. Taken from the manufacturers’ service documentation and kept up to date in our service app.
Short answer: on a Vent-Axia Sentinel Kinetic, 01 means the supply fan has stopped, 02 the extract fan and 03 both fans (01 + 02); 08 and 16 are temperature sensors and 32 the wired remote, and codes add up when several faults happen at once. On an Econiq or current Kinetic Advance, F codes stop the unit, W codes are warnings and N codes are reminders. Duco shows codes as three numbers, such as 1.4.1, in the Duco Installation App and Network Tool.
By Lucas Koc, NZEB ventilation technician · Updated October 2026
On this page
- Vent-Axia
- Sentinel Kinetic B, BH, Plus, High Flow and FH
- Kinetic Advance (older firmware)
- Econiq S, M, L and current Kinetic Advance
- Multivent H and MEV range
- Start-up light flashes (Econiq and Advance)
- WiFi controller light (Econiq and Advance)
- Duco
- All DucoBox units
- DucoBox Energy only
- Self-test codes on the DucoBox Focus and IQ display
- Check Filter message that will not reset
- What a repair costs
- Questions
Vent-Axia fault codes
Find the model and stock reference on the label on the unit. Codes differ between ranges, so check the range before you read the table.
Sentinel Kinetic B, BH, Plus, High Flow and FH
Codes add up when several faults happen at once: 03 = 01 + 02, 24 = 08 + 16. A code shows once the fault has been present for 3 minutes.
| Code | What it means | What to check |
|---|---|---|
| 01 | Supply fan fault | Supply motor not turning. Check the impeller for blockages and the 4-pin motor control and 3-pin power connectors; if sound, replace the supply motor assembly. Parts: 497812 / 417026. |
| 02 | Extract fan fault | Extract motor not turning. Check the impeller and casing for debris and the internal motor cabling; if sound, replace the extract motor assembly. Parts: 497810 / 417028. |
| 03 | Supply + extract fan fault | Both fans offline (01 + 02). Check mains input voltage, inspect the main control PCBA for damage and check wiring harness continuity. Parts: PCBA 497808. |
| 08 | Temperature sensor T1 | Supply duct thermistor disconnected or out of range. Check its connection to the main board; replace the sensor. Parts: 497814. |
| 16 | Temperature sensor T2 | Extract air thermistor fault. Check the T2 connections on the PCBA; replace the sensor leads & cable kit. Parts: 497814. |
| 32 | Wired remote control failure | Main board lost the wired remote. Inspect the RJ11 plugs and the cable run, check for interference, or replace the control board/remote. |
| Room too cold | Room too cold — fan off | Indoor temperature below 5 °C (e.g. heating failure): fans stop to avoid drawing in cold air. The unit runs 2 minutes every hour to probe and resumes above 5 °C. Codes show after a fault has been present for 3 minutes; several faults add up (03 = 01 + 02). |
Kinetic Advance (older firmware)
Two lists, and each adds up on its own: F codes are faults, W codes are warnings. Example: F 05 = F 01 + F 04.
F codes: faults
| Code | What it means | What to check |
|---|---|---|
| F 01 | Left fan fault | Motor locked or disconnected. |
| F 02 | Right fan fault | Motor locked or disconnected. |
| F 04 | Left thermistor fault | T2/T3 left sensors. |
| F 08 | Right thermistor fault | T1/T4 right sensors. |
| F 16 | Left centre thermistor fault | Check the sensor and its connection. |
| F 32 | Right centre thermistor fault | Check the sensor and its connection. |
| F 64 | Left centre temp/humidity sensor fault | Check the sensor and its connection. |
| F 128 | Right centre temp/humidity sensor fault | Check the sensor and its connection. |
W codes: warnings
| Code | What it means | What to check |
|---|---|---|
| W 1 | Left flow sensor faulty | Constant volume limited. |
| W 2 | Right flow sensor faulty | Constant volume limited. |
| W 4 | Left filter sensor faulty | Filter indicator reverts to a timer. |
| W 8 | Right filter sensor faulty | Filter indicator reverts to a timer. |
| W 16 | Supply duct over-pressure | Check for blocked or crushed supply ducting and closed valves. |
| W 32 | Extract duct over-pressure | Check for blocked or crushed extract ducting and closed valves. |
| W 64 | Integrated preheater faulty or disconnected | Check the preheater supply and connection. |
Econiq S, M, L and current Kinetic Advance
F codes stop the unit. W codes are warnings while it keeps running. N codes are reminders.
F codes: the unit stops
| Code | What it means | What to check |
|---|---|---|
| F-01 | Faulty intake temperature sensor | Invalid reading; the unit stops because frost protection depends on it. Replace the sensor assembly. |
| F-02 | Faulty extract temperature sensor | Invalid reading; the unit stops to protect the heat recovery cell from freezing. Replace the sensor assembly. |
| F-03 | Faulty supply fan | Tacho reads zero RPM with power applied. Check the fan harness and impeller rotation; replace the fan motor assembly. |
| F-04 | Faulty extract fan | Tacho reads zero RPM with power applied. Check wiring and plug, clean the impeller, or replace the fan. |
| F-07 | Preheater stuck on | Safety fault: isolate mains power immediately. Check the preheater supply, solid-state relays and temperature cut-outs; replace the preheater PCBA. |
| F-08 | Supply air too cold | Supply air at or below +5 °C. Check handing (LH/RH), summer bypass position, heat recovery cell efficiency, and that the house heating works. |
| F-32 | HMI comms lost | Display not receiving from the mainboard. Check the comms harness and RJ45/patch connections and the mainboard power LED; replace HMI or mainboard. |
W codes: warnings, the unit keeps running
| Code | What it means | What to check |
|---|---|---|
| W-01 | Faulty supply temperature sensor | Heat recovery efficiency figure disabled. Replace the sensor. Clears after the fix and a power cycle. |
| W-02 | Faulty exhaust temperature sensor | Constant volume and condensation detection affected. Replace the sensor. Clears after the fix and a power cycle. |
| W-03 | Preheater temperature | Preheater sensor error or thermal cut-out tripped. Check the manual-reset thermal switch and airflow across the element. Clears after the fix and a power cycle. |
| W-04 | Faulty intake RH sensor | Indication only, ventilation unaffected. Replace if needed. Clears after the fix and a power cycle. |
| W-05 | Faulty extract RH sensor | Humidity auto-boost unavailable. Replace the RH sensor. Clears after the fix and a power cycle. |
| W-06 | Faulty supply flow sensor | Constant volume unavailable; fan runs at fixed speed %. Replace the sensor. Clears after the fix and a power cycle. |
| W-07 | Faulty extract flow sensor | Constant volume unavailable; fan runs at fixed speed %. Replace the sensor. Clears after the fix and a power cycle. |
| W-08 | Faulty filter sensor 1 | Filter life reverts to a timer. Replace the pressure sensor. |
| W-09 | Faulty filter sensor 2 | Filter life reverts to a timer. Replace the pressure sensor. |
| W-10 | Excessive system pressure | Fans at max duty, target flow not reached. Check crushed ducts, closed fire dampers, blocked external grilles, dirty filters. Clears after the fix and a power cycle. |
| W-11 | Preheater tripped | Thermal cut-out tripped. Check the manual-reset thermal switch and airflow across the element. Clears after the fix and a power cycle. |
| W-12 | Filters overdue | Timer expired or filters heavily clogged. Clean or replace the filters and reset the filter timer. Clears automatically once resolved. |
| W-13 | Machine overdue for service | Service timer expired. Wash the heat exchanger, flush the condensate drain, clean the fans, reset the service timer in the engineer menu. Clears automatically once resolved. |
| W-14 | Networked sensor/device lost | A CO2/temp/RH/PIR sensor stopped reporting. Replace batteries, check wireless range or the RS485 bus. Clears automatically once resolved. |
| W-15 | BMS offline | Check Modbus RJ45/terminal wiring, address and speed (default 115200/8/N/1). Clears automatically once resolved. |
| W-16 | Supply fan Modbus offline | Power figures become estimates. Check motor connection pins and comms wires. Clears automatically once resolved. |
| W-17 | Extract fan Modbus offline | Power figures become estimates. Check motor connection pins and comms wires. Clears automatically once resolved. |
| W-18 | Bypass / cell issue | Unusual efficiency reading. Check the summer bypass actuator, cell alignment and seals. Clears automatically once resolved. |
| W-19 | Preheater IO offline | Auxiliary preheater module lost. Check the auxiliary board wiring and power. Clears automatically once resolved. |
| W-20 | Cooling unit offline | Cool-Flow top module lost; cooling disabled. Check the control cable between base unit and top module. Clears after the fix and a power cycle. |
| W-21 | Cooling unit overheating | Compressor overheating; fans go to max. Check filters and the cooling airflow path, or service the refrigeration unit. |
N codes: reminders
| Code | What it means | What to check |
|---|---|---|
| N-01 | Filters due soon | Filter timer within 30 days of expiry. Inspect filters, order replacements. |
| N-02 | Service due soon | Annual service approaching. Schedule maintenance (heat exchanger, condensate trap). |
| N-03 | Networked sensor/device offline | Wireless node temporarily offline. Check batteries or RF path before it becomes W-14. |
| N-04 | Cooling suspended | Pressure trip, overheat protection or isolated power. Wait 15 min; check the top module isolator. |
| N-05 | Cooling ineffective | No temperature drop across the evaporator. Check refrigerant charge and compressor — F-Gas certified technician. |
Multivent H and MEV range
Switch the unit off and on again first. If the code comes back, the fault is real.
| Code | What it means | What to check |
|---|---|---|
| F01 | Control fault — failed start-up check | Power off and on again; if it persists replace the control PCBA. |
| F02 | Motor fault — no RPM | Check the impeller for blockages and internal motor wiring; replace the motor. (Standard MVDC-MS/H models have no RPM feedback.). |
| F03 | Humidity/temp sensor — no value | Check the sensor ribbon cable is seated; replace the internal sensor module (contact tech support for the part). |
| F04 | CO2 sensor — no value | Check wiring between main board and sensor; replace the sensor if needed. |
| F05 | RF/RS485 temp or humidity sensor offline | Check sensor power (battery if wireless) and re-pair it (Multivent manual p. 10). |
| F06 | RF/RS485 CO2 sensor offline | Check sensor mains/battery power and re-pair it (Multivent manual p. 10). |
| F07 | 4-way speed switch (SSU) offline | Check the controller power; reconnect or re-pair the switch. |
| F08 | Alarm interface module (AIM) offline/triggered | Check the alarm system state and the harness between HMI/main board and AIM. |
Start-up light flashes (Econiq and Advance)
Count the red flashes when the unit powers up. The HMI board is the controller; the mainboard is inside the unit.
HMI board (controller)
| Code | What it means | What to check |
|---|---|---|
| 1 flash | RNG failed | HMI board self-test failure. |
| 2 flashes | Flash chip (DS-45DB081E) init failed | HMI board self-test failure. |
| 3 flashes | Storage — flash read/write error | HMI board self-test failure. |
| 4 flashes | LCD driver (UC1677) failed | HMI board self-test failure. |
| 5 flashes | Touch driver (CAP1298) failure | HMI board self-test failure. |
| 6 flashes | Built-in temp/humidity sensor (SHT3x) error | HMI board self-test failure. |
| 7 flashes | ESP32 sync timeout | HMI board self-test failure. |
| 8 flashes | RF868 / wireless auto-tune failed | HMI board self-test failure. |
| 9 flashes | Display app module error | HMI board self-test failure. |
Mainboard (inside the unit)
| Code | What it means | What to check |
|---|---|---|
| 1 flash | RNG failed | Mainboard self-test failure. |
| 2 flashes | Real-time clock init failed | Mainboard self-test failure. |
| 3 flashes | EEPROM error (reserved) | Mainboard self-test failure. |
| 4 flashes | Flash chip (DS-45DB081E) failure | Mainboard self-test failure. |
| 5 flashes | Storage — flash read/write error | Mainboard self-test failure. |
| 6 flashes | External RAM (FM24V01A) failure | Mainboard self-test failure. |
| 7 flashes | Ventilation engine failed to start | Mainboard self-test failure. |
| 8 flashes | Application module init error | Mainboard self-test failure. |
| 9 flashes | Modbus bus init failure | Mainboard self-test failure. |
WiFi controller light (Econiq and Advance)
The light on the WiFi controller shows its connection state.
| Code | What it means | What to check |
|---|---|---|
| Solid white | Idle — paired and connected | Normal operation. |
| Flashing white | App pairing mode | Wait for the phone app to pair (started by holding Menu for 3 s). |
| Slow red flash | WiFi connection error | Cannot reach the router. Reconfigure in AP mode via the app with the correct SSID and key. |
| Fast red flash | Factory reset confirmed | Re-pair the HMI and sensors. |
| Solid light blue | Bootloader mode | Should not appear. Isolate power 30 s and restore; if it persists contact tech support. |
| Solid purple | Firmware update | Wait for it to finish — do not power off. |
| Solid red | Lost the mainboard | Check the internal connector cables and power-cycle the MVHR. |
| Slow red/green flash | WiFi board fault | Replace the WiFi controller board if a power cycle does not clear it. |
Duco error codes
Duco units report errors to the Duco Installation App and the Duco Network Tool. The DucoBox Energy also lists them on its own display.
All DucoBox units
Codes shown in the Duco Installation App and the Duco Network Tool, and on the DucoBox Energy display under INFO → ERROR LIST.
Faults
| Code | What it means | What to check |
|---|---|---|
| 1.4.1 | No response from the extractor fan | Check or replace the fan. |
| 3.1.3 | The temperature sensor of the ODA (supply air from outside to the unit) cannot be read | Check or replace the sensor. |
| 3.1.5 | The temperature sensor of the ODA (supply air from outside to the unit) is short-circuited | Check or replace the sensor. |
| 3.1.6 | The temperature sensor of the ODA (supply air from outside to the unit) has a bad connection | Check or replace the sensor. |
| 4.1.3 | The temperature sensor of the ETA (extract air from the house to the unit) cannot be read | Check or replace the sensor. |
| 4.1.5 | The temperature sensor of the ETA (extract air from the house to the unit) is short-circuited | Check or replace the sensor. |
| 4.1.6 | The temperature sensor of the ETA (extract air from the house to the unit) has a bad connection | Check or replace the sensor. |
| 6.1.3 | The temperature sensor of the EHA (extract air from the unit to the outside) cannot be read | Check or replace the sensor. |
| 6.1.5 | The temperature sensor of the EHA (extract air from the unit to the outside) is short-circuited | Check or replace the sensor. |
| 6.1.6 | The temperature sensor of the EHA (extract air from the unit to the outside) has a bad connection | Check or replace the sensor. |
| 16.1.3 | The pressure sensor for the extract air cannot be read | Check or replace the sensor. |
| 28.4.1 | No response from the supply fan | Check or replace the fan. |
| 29.1.3 | The pressure sensor for the supply air cannot be read | Check or replace the sensor. |
| 30.1.3 | The temperature sensor of the SUP (supply air from the unit to the house) cannot be read | Check or replace the sensor. |
| 30.1.5 | The temperature sensor of the SUP (supply air from the unit to the house) is short-circuited | Check or replace the sensor. |
| 30.1.6 | The temperature sensor of the SUP (supply air from the unit to the house) has a bad connection | Check or replace the sensor. |
| 33.10.1 | Outdoor temperature too low, ventilation is switched off permanently | Restart the DucoBox later. |
| 35.17.1 | The value of the temperature sensor is too low | Check or replace the sensor. |
| 35.17.2 | The value of the temperature sensor is too high | Check or replace the sensor. |
| 35.17.3 | The value of the temperature sensor cannot be read | Check or replace the sensor. |
| 36.24.1 | The connection to the weather station is lost | Check the connection. |
| 36.24.2 | The connection to the outdoor temperature sensor is lost | Check the connection. |
| 36.24.3 | The connection to the motor of the DucoGrille Close 105 is lost | Check or replace the motor. |
| 36.24.6 | The connection to the Duco ExtensionHub is lost | Check or replace the Duco ExtensionHub. |
| 37.17.1 | The value of the CO2 sensor is too low | Check or replace the sensor. |
| 37.17.2 | The value of the CO2 sensor is too high | Check or replace the sensor. |
| 37.17.3 | The value of the CO2 sensor cannot be read | Check or replace the sensor. |
| 40.17.1 | The value of the humidity sensor is too low | Check or replace the sensor. |
| 40.17.2 | The value of the humidity sensor is too high | Check or replace the sensor. |
| 40.17.3 | The value of the humidity sensor cannot be read | Check or replace the sensor. |
| 42.22.1 | The number of connected valves is too high | The maximum number is stated in the manual. DucoBox Energy: See installation manual DB Energy Comfort (Plus) or installation manual DB Energy Premium. |
| 42.22.2 | The number of connected valves is too low | The minimum number is 2. DucoBox Energy: See installation manual DB Energy Comfort (Plus) or installation manual DB Energy Premium. |
| 42.22.3 | The number of connected control valves is too high | The maximum number is 11. |
| 42.22.4 | The number of connected control valves is too low | The minimum number is 2. |
| 42.22.5 | The number of connected CO2 control valves is too high | The maximum number is 7. |
| 53.28.1 | The motor is locked by a manual action | |
| 53.28.2 | The motor does not respond to manual action | Check the communication of the paired user controller. |
| 53.28.3 | The motor cannot be controlled automatically due to missing data | Check the installation. |
| 54.29.1 | The connection to the motor is lost | Check or replace the motor. |
| 54.29.2 | The motor reports an error | Check the installation. |
| 54.29.3 | The desired position of the motor cannot be reached | Check or replace the motor. |
| 56.31.1 | An error occurred with a Duco RF component | Check or replace the component. |
| 56.31.2 | An error occurred with a Duco Wired component | Check or replace the component. |
Warnings
| Code | What it means | What to check |
|---|---|---|
| 31.19.1 | The filters are dirty | Replace the filters. |
| 32.1.1 | Outdoor temperature too low, ventilation is switched off for 8 hours | |
| 43.23.1 | The adjustment has not yet been done or has failed | Do the adjustment (again). DucoBox Energy: See installation manual DB Energy Comfort (Plus) or installation manual DB Energy Premium. |
| 43.23.2 | The desired flow rate cannot be achieved | Check the entire installation. DucoBox Energy: See installation manual DB Energy Comfort (Plus) or installation manual DB Energy Premium. |
| 43.23.11 | The requested configuration is not correct: the sum of the supply flow rate is greater than the maximum allowed flow rate | Do the adjustment again. |
| 43.23.12 | The calibration is interrupted by a manual action on the display | Do the adjustment again. |
| 43.23.13 | An error occurred while calculating the resistance | Check the installation and do the adjustment again. |
| 43.23.14 | An error occurred during calibration | Check the installation and do the adjustment again. |
| 43.23.15 | The adjustment has not yet been done or has failed | Do the adjustment (again). |
| 43.23.16 | The adjustment is interrupted via the Duco Installation App or by an API call | Do the adjustment again. |
| 43.23.17 | The adjustment is interrupted by a manual action via the DNT tool | Do the adjustment again. |
| 43.23.18 | The adjustment is interrupted by activating ‘installer mode’ | Do the adjustment again. |
| 43.23.19 | A timeout occurred | Do the adjustment again. |
| 43.23.20 | The prepared configuration contains errors. Too many or too few multi-zone control valves are connected to the ventilation system | Check the installation and do the adjustment again. |
| 43.23.21 | The calibration is interrupted due to missing data from the pressure sensor | Check or replace the sensor. |
| 44.6.1 | There is no connection to the pre-heater | Check the connection. DucoBox Energy: See installation manual DB Energy Comfort (Plus) or installation manual DB Energy Premium. |
| 46.1.3 | The outdoor temperature is not available | Check the connection and the paired sensors. |
| 47.1.3 | Wind speed is not available | Check the connection and the paired sensors. |
| 48.1.3 | Wind direction is not available | Check the connection and the paired sensors. |
| 49.1.3 | The light incidence is not available | Check the connection and the paired sensors. |
| 50.1.3 | Precipitation is not available | Check the connection and the paired sensors. |
| 51.26.1 | The motor of the DucoGrille Close has gone out of its operating range | Check or replace the motor. |
| 51.26.2 | The motor of the DucoGrille Close 105 cannot move due to mechanical overload | Check the motor for obstructions and the mechanical end-stops. |
| 51.26.4 | The connection to the motor of the DucoGrille Close 105 is lost | Check the connection. |
| 51.26.5 | The gear of the motor of the DucoGrille Close 105 has come loose or is free | Check that the push button is not pressed or replace the motor. |
| 51.26.6 | An internal activity is in progress, preventing the motor from operating in normal mode | De-energise the DucoGrille Close 105 and start the system again. |
| 55.30.1 | The temperature of the outdoor temperature sensor cannot be read | Check or replace the sensor. |
| 57.32.1 | An error occurred in the control of the ventilative cooling | Check the installation. |
| 58.32.1 | An error occurred in the control of the solar shading | Check the installation. |
| 60.34.1 | The value of the temperature sensor of the DucoGrille Close 105 is too high | Check or replace the sensor. |
| 60.34.2 | The value of the temperature sensor of the DucoGrille Close 105 is too low | Check or replace the sensor. |
| 60.34.3 | The value of the temperature sensor of the DucoGrille Close 105 has been too low for at least 1 hour | Check or replace the sensor. |
| 60.34.4 | The value of the temperature sensor of the DucoGrille Close 105 has been too low for at least 1 day | Check or replace the sensor. |
| 60.34.5 | The value of the temperature sensor of the DucoGrille Close 105 has been too low for at least 1 week | Check or replace the sensor. |
| 61.35.1 | The prepared configuration contains errors | Check the configuration. |
| 61.35.2 | The prepared configuration contains errors. One or more components are not linked to a group | Check the configuration. |
| 61.35.3 | The prepared configuration contains errors. One or more components are linked to more than one group | Check the configuration. |
| 62.36.1 | The current time is not set. As a result, certain functionalities are not available | Set the time. |
Information
| Code | What it means | What to check |
|---|---|---|
| No error code | The DucoBox is live but does not respond | Check or replace the circuit board. |
| 52.27.1 | Weather protection is activated by rain | |
| 52.27.2 | Weather protection is activated by wind | |
| 52.27.3 | The weather station is not recording any data | Check the installation. |
| 52.27.4 | Weather protection is activated by wind and rain | |
| 52.27.5 | The value of the temperature sensor has been constant for a long time | Check or replace the sensor. |
| 52.27.6 | Weather protection is activated by external logic | |
| 52.27.7 | The weather protection of a group to which this component belongs, is activated |
DucoBox Energy only
These codes appear only on the DucoBox Energy (Comfort, Comfort Plus and Premium).
| Code | What it means | What to check |
|---|---|---|
| 3.1.1 | ODA (outdoor air to the unit) temperature sensor value is too low | Check and/or replace the temperature sensor. |
| 3.1.2 | ODA (outdoor air to the unit) temperature sensor value is too high | Check and/or replace the temperature sensor. |
| 3.1.4 | ODA (outdoor air to the unit) temperature sensor has been measuring the same temperature for a long time | Check and/or replace the temperature sensor. |
| 4.1.1 | ETA (extract air from the house to the unit) temperature sensor value is too low | Check and/or replace the temperature sensor. |
| 4.1.2 | ETA (extract air from the house to the unit) temperature sensor value is too high | Check and/or replace the temperature sensor. |
| 4.1.4 | ETA (extract air from the house to the unit) temperature sensor has been measuring the same temperature for a long time | Check and/or replace the temperature sensor. |
| 6.1.1 | EHA (exhaust air from the unit to the outside) temperature sensor value is too low | Check and/or replace the temperature sensor. |
| 6.1.2 | EHA (exhaust air from the unit to the outside) temperature sensor value is too high | Check and/or replace the temperature sensor. |
| 6.1.4 | EHA (exhaust air from the unit to the outside) temperature sensor has been measuring the same temperature for a long time | Check and/or replace the temperature sensor. |
| 16.1.1 | Extract air pressure sensor value is too low | Check and/or replace the pressure sensor. |
| 16.1.2 | Extract air pressure sensor value is too high | Check and/or replace the pressure sensor. |
| 16.1.4 | The extract air pressure sensor has been measuring the same value for a long time | Check and/or replace the pressure sensor. |
| 16.1.5 | The extract air pressure sensor is short-circuited | Check and/or replace the pressure sensor. |
| 16.1.6 | The extract air pressure sensor has a bad connection | Check and/or replace the pressure sensor. |
| 29.1.1 | The supply air pressure sensor is too low | Check and/or replace the pressure sensor. |
| 29.1.2 | The supply air pressure sensor is too high | Check and/or replace the pressure sensor. |
| 29.1.4 | The supply air pressure sensor has been measuring the same value for a long time | Check and/or replace the pressure sensor. |
| 29.1.5 | The supply air pressure sensor is short-circuited | Check and/or replace the pressure sensor. |
| 29.1.6 | The supply air pressure sensor has a bad connection | Check and/or replace the pressure sensor. |
| 30.1.1 | SUP (supply air from the unit to the house) temperature sensor value is too low | Check and/or replace the temperature sensor. |
| 30.1.2 | SUP (supply air from the unit to the house) temperature sensor value is too high | Check and/or replace the temperature sensor. |
| 30.1.4 | SUP (supply air from the unit to the house) temperature sensor has been measuring the same temperature for a long time | Check and/or replace the temperature sensor. |
| 32.10.1 | Outdoor temperature too low – ventilation is switched off for 8h | |
| 44.6.2 | A Duco Pre-Heater is connected to the DucoBox | Go to settings to configure it. |
Self-test codes on the DucoBox Focus and IQ display
Shown in the display menu under SelfTst. The first characters are the node number of the component with the error; the code after # is the error.
| Code | Error |
|---|---|
| #0 | CO2 error |
| #1 | RH error |
| #2 | Temperature error |
| #3 | Low battery |
| #4 | Fan error |
| #5 | Motor error |
| #6 | Communication error |
| #7 | Clima strip error |
“Check Filter” message that will not reset
This is a reminder, not a fault code. If it comes back straight after a reset, the usual causes are:
- Filters fitted the wrong way round, or the wrong grade
- A faulty filter timer
- A blocked airflow path
- Drifted pressure sensors (Kinetic Advance SX)
Step by step: how to reset the Vent-Axia filter message and change the filters.
What a repair costs
Typical prices in Ireland. The final cost depends on the model, access to the unit and the condition of the ducting.
| Repair | Typical price |
|---|---|
| Diagnostic visit | €120–€150 |
| Fan motor (Kinetic codes 01 and 02) | €250–€350 per fan |
| Temperature or humidity sensor | €90–€160 |
| Controller or wiring | €150–€220 |
| Summer bypass actuator | €250–€360 |
| Condensate drain correction | €80–€180 |
Code still showing?
Switch the unit off at the isolator before opening it. Fan, fuse and circuit board faults need a technician. We find the fault, quote the repair and fix it: book a Vent-Axia repair, call us on 057 851 1416 (answered straight away), or send us a message.
Questions
What does code 03 mean on a Vent-Axia Kinetic?
Both fans have stopped. Kinetic codes add up, and 03 is 01 (supply fan) plus 02 (extract fan). Check the mains supply first; if both fans are still off, the main circuit board is the usual cause.
Can I reset a Vent-Axia fault code myself?
You can switch the unit off at the isolator and back on. If the same code comes back, the fault is real and needs to be found.
Is it safe to leave the unit running with a fault code?
With 01, 02 or 03 one or both fans have stopped, so the house is not being ventilated and moisture builds up quickly. Book a repair within days, not weeks.
Where do I find Duco error codes?
In the Duco Installation App or the Duco Network Tool, and on the DucoBox Energy display under INFO → ERROR LIST. The DucoBox Focus and IQ display also show self-test codes under SelfTst.
Do older units get repaired or replaced?
It depends on the fault and the age of the unit. After the diagnostic visit you get a price for the repair and, when a replacement makes more sense, a price for that too, before any work starts.
Eco Vent Ireland is an independent service company, not affiliated with Vent-Axia or Duco. Codes are taken from the manufacturers’ service documentation and installation manuals.