Viessmann MatriX Service Instructions Manual page 35

Diagnostics
(cont.)
Fault System
code characteristics
31 Fault on gas burner
control unit
32
35
36 Fan speed during
start−up or during
operation is longer
than 5 s outside the
set range, speed for
ignition setting or
start−up output during
operation is not
reached
37 Fan does not reach set
speed
42 Gas burner control
unit remains in
start−up position, no
start in spite of heat
demand
4E Fault on gas burner
control unit
Cause
Fault in feedback from
gas safety valves,
output relay does not
activate
Fault in feedback from
auxiliary start−up
valve, output relay
does not activate
Fault in feedback from
ignition, output relay
does not activate
Fan faulty,
cable "100a" faulty or
broken
Fan faulty,
cable "100" or "100a"
faulty or broken, fan
blocked by a foreign
body
Safety chain broken
Internal fault
Troubleshooting
Remedy
Replace gas burner
control unit
Check cables and
replace cable "100a"
or fan if necessary
Check cable "100"
or "100a", if
necessary replace
cable or fan, remove
foreign body
Check jumper B 2
(plug fJ) of the safety
chain on the gas
burner control unit
Replace gas burner
control unit
35