Baxi / Main / Potterton · Compact, Duo-tec, Platinum, Assure and EcoBlue platform
E83 / E84 / E85 / E86 / E87No communication
This code applies to Baxi Platinum Compact Combi, Baxi Duo-tec Compact Combi, Baxi Megaflo Compact System, Main Eco Compact Combi & System, Baxi 600 Combi & System, Baxi 800 Combi & System, Baxi Duo-tec Combi, Baxi Assure Combi & System, Baxi Platinum Combi, Potterton Assure Combi & System, Baxi Platinum+ Combi, Baxi Megaflo System, Baxi EcoBlue Combi & System. Fault codes narrow down the likely problem, but they do not replace a model-specific diagnosis.
What you can safely check
- Power-cycle or reset once only if the user manual specifically permits it.
- If the message remains, arrange an engineer.
How an engineer may fix it
Check configuration, coding, communication buses, plugs, wiring, power supply and control boards; configure, repair or replace the failed control component.
Manufacturer source: Baxi Professional — Boiler Error Codes. Checked 15 August 2026. The appliance manual and an engineer’s on-site diagnosis take precedence. Never remove the boiler case yourself.