BoilerFaultCodes 5A
Lead break, flow sensor
Viessmann Vitodens 100-W B1HA-19 Fault codes & diagnostics
26 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
System Natural GasLPG 2014-2016 Discontinued
GC Number 41-819-36
Download the Viessmann Vitodens 100-W B1HA-19 manual
PDF
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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. 26 Unrated
Just want the most common Viessmann Vitodens 100-W B1HA-19 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 26 documented codes
Tap any card for details
10
Short circuit, outside temperature sensor
18
Lead break, outside temperature sensor
30
Short circuit, boiler water temperature sensor
38
Lead break, boiler water temperature sensor
50
Short circuit, cylinder temperature sensor
51
Short circuit, outlet temperature sensor
52
Short circuit, flow sensor
58
Lead break, cylinder temperature sensor
59
Lead break, outlet temperature sensor
Showing 11–20 of 26
A9
Communication error, OpenTherm device
b0
Short circuit, flue gas temperature sensor
b8
Lead break, flue gas temperature sensor
E3
Fault in safety chain
E5
Internal fault
F0
Internal fault
F1
Max. flue gas temperature exceeded
F2
Temperature limiter has responded
F3
Flame signal is already present at burner start
F4
No flame signal detected
Showing 21–26 of 26
F8
Fuel valve closes too late
F9
Fan speed too low during burner start
FA
Fan idle state not reached
FC
Electrical fan control (control unit) faulty
Fd
Burner control unit fault
FF
Burner control unit fault