Viessmann Vitodens 300 - Page 80

Displayed
fault c ode
Con-
st.
Weat -
her-
com-
p.
System
character-
istics
Cause Remedy
b8 X X Burner
blocked
Flue gas tem-
perature sen-
sor lead break
Check the flue gas
temperature sensor
(see page 89)
b1 X X Control
mode
Communica-
tion fault –
programm ing
unit (inter nal)
Check connecti ons
andreplacethepro-
gramming unit, if
necessary
b4 X X Emissions
test mode
Internal fault Replace control unit
b5 X X Control
mode
Internal fault Replace control unit
b7 X X Burner
blocked
Boiler coding
card missing,
faulty or incor-
rect card
inserted
Insert the b oiler
coding card or
replace, if faulty
bA X M ixer M2
continues
to control
Communica-
tion fault -
extension k it
for mixer cir-
cuit M2
Check the exten-
sion kit connections
and cod ing. Star t
the extension k it.
bC X Control
mode with-
out remote
control
Communica-
tion fault -
Vitotrol remote
control heating
circuit A1
Check connecti ons,
cable, coding
address A0 and the
remote control DIP
switches
bd X Control
mode with-
out remote
control
Communica-
tion fault -
Vitotrol remote
control heating
circuit M2
Check connecti ons,
cable, coding
address A0 and the
remote control DIP
switches
bE X Control
mode
Vitotrol remote
control incor -
rectly encoded
Check the remote
control DIP switch
settings
bF X Control
mode
Incorrect LON
communica-
tion module
Replace the L ON
communicati on
module
Checking and acknowledging faults (cont.)
80
Troubleshooting
5692 537 GB