Viessmann VITOLADENS 300-W, Service Instructions For Contractors

Page: 65 / 108

65
Fault code
on the dis-
play System characteris-
tics Cause Measures
b1 Control mode as per
delivered condition Communication
fault, programming
unit (internal) Check connections and
replace the programming
unit if required.
b4 Controls as if the out-
side temperature
were 0 °C Internal fault Replace the control unit.
b5 Control mode as per
delivered condition Internal fault Replace the control unit.
b7 Burner blocked Boiler coding card
missing, faulty or
incorrect boiler
coding card Plug in boiler coding card
or replace it, if faulty.
b8 Burner blocked Lead break, flue
gas temperature
sensor Check the flue gas tem-
perature sensor (see
page 72).
bA Mixer M2 regulates to
20 °C flow tempera-
ture Communication
fault, extension kit
for heating circuit
with mixer M2 Check extension kit con-
nections and code. Start
the extension kit.
bC Control mode without
remote control Communication
fault, Vitotrol
remote control,
heating circuit A1 Check connections,
cable, coding address
"A0" and the remote con-
trol DIP switches.
bd Control mode without
remote control Communication
fault, Vitotrol
remote control,
heating circuit with
mixer M2 Check connections,
cable, coding address
"A0" and the remote con-
trol DIP switches.
bE Control mode Vitotrol remote
control incorrectly
programmed Check remote control DIP
switch settings (see
page 88).
bF Control mode Incorrect LON
communication
module Replace the LON commu-
nication module.
C2 Control mode Lead break, KM
BUS to solar con-
trol unit Check the KM BUS, the
solar control unit and cod-
ing address "54".
Troubleshooting
Fault codes
(cont.)
5692 799 GB