Baxi 600 series Fault Codes

The Baxi 600 — 600 Combi 2 above all — is the volume seller of Baxi's current line-up: a compact, affordable boiler sharing the 800's modern platform in a smaller, simpler package. It uses the same two-part fault-code language as the 800 (E.XX-.XX codes, with H-codes for temporary blockings), so a code on a 600 means the same as on an 800. The 600 is frequently chosen for flats and smaller homes, often replacing much older boilers — so for many owners it is their first meeting with a condensing boiler's habits: the pressure gauge that wants watching, the condensate pipe that dislikes hard frosts, the codes that actually explain themselves. The essentials are quick to learn, and each code below links through to its full cause-and-fix page.

Where 600 series fault codes appear

The 600 has a compact digital display: status in normal running, the two-part code (E.01-.04 style) on a fault, H-prefixed for temporary conditions. Record both halves exactly — a photo is the reliable method — before resetting or calling anyone.

Resetting a Baxi 600 series

Press and hold the reset button briefly; the boiler retries. Low-pressure codes want a top-up to 1–1.5 bar via the filling loop first. H-codes usually resolve themselves; persistent ones, and any E-code that returns after a single reset, deserve a Gas Safe engineer's diagnosis rather than repeat resets.

Common 600 series problems

On the 600 the recurring themes are pressure loss (small systems show pressure drops quickly), winter ignition lockouts from frozen condensate runs — compact installs often route the pipe externally — and the occasional sensor code. It is a current, well-warrantied range: register the warranty, keep the annual service, and most of this page stays theoretical.

Most common 600 series fault codes

See all Baxi fault codes →

Last reviewed 25 August 2026.