BoilerFaultCodesWhat the manual says
Manufacturer manualZone ambient set point °C
Shared across the 400 Combi 2 range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
DIY fix possible
Check your thermostat or room controller to see if you have accidentally entered a settings menuPress the 'Reset' or 'Back' button on the boiler interface to return to the main displayRefer to your user manual to navigate out of the advanced settings view
Find a Gas Safe engineer
Search the official register →
Boiler cover options
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
Approved partner
Get a quote →
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Affiliate links. We may earn a commission at no extra cost to you.
All 110 fault codes on the 400 Combi 2
Seeing a different code? Every code this model can display, in one place.
A.00 .28A.00 .29A.00.34A.02 .37A.02 .45A.02 .46A.02 .48A.02 .49A.02 .54A.02 .76A.02.06A.02.36A.02.55AM001AM010AM011AM012AM014AM015AM016AM018AM019AM024AM027AM036AM037AM040AM091AM101AP073AP079BM000CM030CM120CM210CM280CP000CP020CP210CP230CP470CP480CP490CP780DM001DM002DM005DM009DM019DM029DP430DP440E.00.04E.00.05E.00.16E.00.17E.00.20E.00.21E.01.04E.01.12E.01.17E.01.20E.02 .13E.02 .35E.02 .39E.02 .47E.02.17E.04 .29E.04 .54E.04.01E.04.02E.04.03E.04.08E.04.10E.04.12E.04.13E.04.17E.04.18E.04.23GM001GM002GM003GM004GM007GM008GM012GM013GM044H.00 .81H.00.42H.01.00H.01.05H.01.08H.01.14H.01.18H.01.21H.02 .70H.02.00H.02.02H.02.03H.02.04H.02.05H.02.07H.02.09H.02.10H.03 .54H.03.00H.03.02H.03.05