Viessmann Vitotwin 300-W Installation And Service Instructions For Contractors page 124

Troubleshooting
Fault messages
Fault mes- Cause
sage
"83: BSB BUS connection short circuit Check BUS cable
short cir-
cuit"
"84: BSB ad- Programming unit or con-
dress con- necting cable to program-
flict" ming unit faulty.
More than one remote con-
trol unit is assigned to a heat-
ing circuit.
"85: BSB ra- Wireless connection inter-
dio commu- rupted (e.g. remote control
nication" unit)
"91: Data Connections interrupted or
loss in EE- control unit PCB faulty.
PROM"
"92: Device
electronics
error"
"95: Time of Wrong time set
day invalid"
"96: Minor Software error
SW error"
"97: SW or Fault on control unit PCB.
HW failure"
"98: Exten- Fault in extension module for
sion module heating circuit with mixer 1.
1"
"99: Exten- Fault in extension module for
sion module heating circuit with mixer 2.
2"
"102: Clock Power reserve for time
without switch exhausted (appliance
backup" disconnected from the power
supply for a long time).
"105: Main- Service due.
tenance
message"
124
(cont.)
Remedy
Check remote control - heat-
ing circuit assignment. Cod-
ing addresses 40, 42, 44,
46.
Check programming unit and
connecting cable
Restore wireless connection
(see installation instructions
for remote control unit)
Check all plug-in connec-
tions on the control unit PCB.
Replace control unit PCB if
necessary (see page 138).
Reset time
Replace the control unit PCB
(see page 138).
Carry out service reset. Re-
place control unit PCB if nec-
essary (see page 138).
Check plug-in connections
and connecting cables.
Check codes. Replace ex-
tension module if necessary.
Switch on appliance and re-
set time (see operating in-
structions).
Service the appliance.
Re-
set-
ting
NRP
AR
NRP