Error codes
Bonaire Ducted Heating Error Codes Explained
Every Bonaire gas ducted heater fault code in plain English, what you can safely check yourself, and when to stop and book a licensed repair in the Macedon Ranges.
Updated 10 September 2026 by the Macedon Ranges Gas & Air team
Bonaire heaters flag faults with a numbered code on the controller. The meanings below are the plain-English summaries we published on our original guide, drawn from manufacturer documentation. Flame faults, pressure losses, gas valve errors and overheats are the common ones, and many are repaired on the first visit. If you see a code, switch the unit off and book a licensed technician rather than resetting it repeatedly.
Bonaire error codes
| Code | What it usually means |
|---|---|
| Error 2 | Overheat prevention or outlet temperature too high |
| Error 3 | Overheat detected by thermistor or overheat switch |
| Error 4 | Temporary parameter storage fault |
| Error 6 | Pressure lost after combustion fan operation check |
| Error 8 | Flame not detected during ignition |
| Error 9 | Flame unstable or flame out immediately after ignition |
| Error 10 | Flame lost during heating |
| Error 11 | Shutdown due to transient problem |
| Error 12 | Thermostat on at power-up |
| Error 13 | Condensate detected (6-star heaters) |
| Error 14 | Condensate sensor short or open circuit (6-star heaters) |
| Error 15 | System timing error, mains frequency not 50Hz or internal control fault |
| Error 16 | Modulating valve overcurrent |
| Error 17 | Thermistor location fault |
| Error 18 | Thermistor open circuit |
| Error 19 | Thermistor short circuit |
| Error 20 | Overheat switch or thermistor fault after cooldown |
| Error 21 | Too many overheats from overheat switch |
| Error 22 | Too many combustion fan drive errors or possible flue restriction |
| Error 23 | Pressure detected in idle state |
| Error 25 | Pressure not detected during initial combustion fan test |
| Error 26 | Too many pressure losses |
| Error 27 | Low 24V AC |
| Error 28 | Too many overheats from thermistor |
| Error 29 | Flame sense fault |
| Error 30 | Too many ignition attempts |
| Error 31 | Too many flame validation attempts |
| Error 32 | No 24V AC |
| Error 33 | Modulating valve open circuit |
| Error 34 | Modulating valve short circuit |
| Error 35 | Circulation fan drive fault |
| Error 36 | Combustion fan drive fault |
| Error 37 | AC input fault |
| Error 38 | System error or A-D converter fault |
| Error 39 | System error or MCU fault |
| Error 40 | False flame detected with no gas |
| Error 41 | Primary gas valve not on |
| Error 42 | Primary gas valve stuck on |
| Error 43 | Primary gas valve lost during run |
| Error 44 | Secondary gas valve not on |
| Error 45 | Secondary gas valve stuck on |
| Error 46 | Secondary gas valve lost during run |
| Error 48 | MCU communication error |
| Error 49 | MCU communication fault |
| Error 50 | Remote MCU not shut down |
| Error 51 | Incorrect remote MCU state |
| Error 52 | Mismatch in MCU information |
| Error 53 | Unidentified or transient internal control fault |
| Error 54 | Remote MCU lockout |
| Error 55 | Unidentified or transient internal control fault |
| Error 56 | Too many pressure losses |
| Error 57 | Invalid model or model dongle fault |
| Error 58 | Maximum number of resets exceeded |
Before you do anything else
A fault code is the heater protecting itself. Most codes mean the control board has detected something outside its limits and shut the burner down. The safe things a homeowner can do are limited, and they are the same for every brand:
- Turn the heater off at the controller and leave it off for a minute or two, then turn it back on once. If the code returns, stop; repeated resetting can mask a fault the heater is trying to warn you about.
- Check the switchboard for a tripped circuit and check that the heater’s isolator has not been switched off.
- Check the return air filter. A badly blocked filter causes overheat and airflow faults on every brand. Clean or replace it if it is dirty.
- Do not open the heater, touch gas fittings, wiring or the flue, or attempt any repair yourself. Gas heater faults need a licensed technician.
- If you smell gas, turn the heater off, turn off the gas at the meter if you can, open windows, do not operate electrical switches near the smell, and call your gas distributor’s emergency line before anyone else.
When to stop and book a repair
Any code that comes back after one reset. Any flame, ignition, gas valve, overheat, rollout or flue-related code, first time. Any code accompanied by a smell, soot marks around the unit, headaches while the heater runs, or a heater that keeps cutting out. Tell us the brand, the code and what the unit is doing when you book a repair and the technician arrives with the likely parts.
Other brands
Brivis and Rinnai error codes, Braemar error codes, or the error code hub. See also our Bonaire page and gas ducted heating service.
Need it done?
Gas Ducted Heating Repairs
Heater not starting, blowing cold or showing a fault code? Licensed in-house technicians repair Brivis, Rinnai, Braemar and Bonaire heaters across the Ranges.
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Related guides
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Brivis and Rinnai Ducted Heating Error Codes Explained
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Heater Error Codes Explained by Brand
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Gas Ducted Heater Not Working? Common Faults Explained
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Book a repair
Tell us what the system is doing. A photo of the controller or the unit helps, but is not needed.
Prefer to talk? Call 1300 369 400, monday to friday 8:00am to 5:00pm, Saturday 9:00am to 1:00pm.