Baxi / Main / Potterton · Compact, Duo-tec, Platinum, Assure and EcoBlue platform
E385 / 165Supply voltage too low
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
- Check for a wider power cut or a tripped consumer-unit circuit without removing the boiler case.
- Use a qualified electrician or Gas Safe engineer for further diagnosis.
How an engineer may fix it
Verify supply voltage, polarity, earthing, fuses, harnesses and appliance electronics; correct the electrical supply or replace the failed 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.