Overview
The E83 fault on a Baxi Avanta is a communication fault – the boiler is telling you that two critical parts are not 'talking' correctly. In many Baxi documents E83 is grouped with other E8x codes that point to internal communication problems (PCB, gas valve control circuit) or occasionally fan-related faults depending on model and firmware. Practically this means the boiler may lock out, stop supplying heating or hot water, and display E83 until the cause is resolved. Causes vary from simple to serious: temporary glitches (power spikes, wireless control drop-out), low battery or lost pairing on external/wireless controls, loose or corroded wiring connections, a failed fan or gas-valve driver, or a faulty main PCB. Severity is moderate to high because the fault affects controls for gas and ignition; if a simple reset or control re-pairing clears it that's fine, but any suspected fault with the PCB, gas valve or internal wiring should be handled by a Gas Safe registered engineer. Do not attempt to access or repair gas or PCB components yourself.
Possible Cause: Fan fault normally E8
Troubleshooting Steps
Safety precautions:
- If you smell gas, leave the property immediately and call the gas emergency number. Do not operate electrical switches or the boiler.
- Isolate the boiler electrically before opening panels. If you are unsure, do not open the boiler casing.
- Do not attempt internal repairs to the PCB, gas valve, fan or gas pipework unless you are a Gas Safe registered engineer.
Initial checks homeowners can do:
1. Note the exact fault code, display behaviour and when it happened (time, whether heating/hot water was on). Take a photo of the display.
2. Try a basic reset: locate the boiler reset button (often marked with a flame symbol or 'reset'), press and hold for 5–10 seconds or switch the boiler off at the mains for 60 seconds then back on. If the fault clears and does not return, monitor the boiler for recurrence.
3. Check external controls: make sure room thermostat, programmer/timer or wireless controls are powered, calling for heat, and correctly paired. Replace batteries in wireless thermostats and re-sync/pair per the thermostat manual.
4. Check mains power to the boiler and the display is normal. Ensure any fused switches for the boiler are on.
5. Check system water pressure on the pressure gauge (target ~1–1.5 bar cold). If pressure is low, top up using the filling loop according to the boiler manual, then re-test. Do not repeatedly top up to mask an underlying leak.
Specific diagnostics and next steps:
1. After the reset and the simple checks above, if E83 returns, do not keep resetting repeatedly. Repeated lockouts can indicate a persistent safety fault or intermittent wiring problem.
2. If you have a wired external thermostat or programmer, visually inspect accessible wiring terminals for loose connections (at the external control end). Only tighten external terminals if you are confident and the mains is isolated; otherwise leave it for the engineer.
3. For wireless controls, re-pair the thermostat and receiver following the manufacturer’s instructions. Replace receiver batteries if fitted. Loss of wireless communication can produce an E83-type error.
4. Record patterns: does the fault occur after a power cut, when the boiler first fires, intermittently with weather, or when a particular control is used? This information is valuable for diagnosis.
5. If the fault persists despite the above, contact a Gas Safe registered engineer. Provide them with the fault code, photos, timings and what you’ve already tried. The engineer will carry out safe electrical and component tests (multimeter checks, PCB diagnostics, fan and gas valve driver testing), check internal wiring and connectors, and replace defective parts (fan, gas valve/driver or PCB) only if necessary.
Final note:
- E83 can be a minor temporary communication fault or a sign of a failed PCB/gas-valve/driver or fan. Because the fault affects gas control and ignition, professional diagnosis and repair by a Gas Safe registered engineer is strongly recommended if the simple homeowner checks do not resolve it. Do not attempt internal gas or PCB repairs yourself.
Helpful Resources
No specific resources found.
Boiler Manual
Download the official PDF manual for the Baxi Avanta Range.