BoilerFaultCodes A7
Hot water NTC sensor defective.
Worcester Bosch Highflow 400 Electronic BF Fault codes & diagnostics
13 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Natural Gas 2002-2005 Discontinued
GC Number 47-311-62
Download the Worcester Bosch Highflow 400 Electronic BF manual
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The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 13 Unrated
Just want the most common Worcester Bosch Highflow 400 Electronic BF faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 13 documented codes
Tap any card for details
A8
Break in communication
AC
Module not detected.
b1
Code plug not detected.
C1
Fan speed too low.
d3
Jumper 8-9 not detected.
E2
CH flow NTC sensor defective
E9
Safety temp. limiter in CH flow has tripped.
EA
Flame not detected.
F0
Internal error.
F7
Flame detected even though appliance switched off.
FA
Flame detected after gas shut off.
Fd
Reset button pressed by mistake.