Viessmann VITODENS 200-W Installation And Service Instructions Manual page 97

Fault messages
(cont.)
Displayed fault System characteristics
code
49 Mixer is being closed.
4C Mixer is being closed.
4D Mixer is being closed.
50 No DHW heating by the boil-
er
51 No DHW heating by the boil-
er
58 No DHW heating by the boil-
er
59 No DHW heating by the boil-
er
70 Burner blocked
71 Burner blocked
73 Burner blocked
74 Burner blocked or in a fault
state
75 Burner blocked or in a fault
state
76 Burner blocked or in a fault
state
Cause
Incorrect assignment of
extension for mixer, heat-
ing circuit 2
Lead break, flow tempera-
ture sensor, heating circuit
3 (with mixer)
Incorrect assignment of
extension for mixer, heat-
ing circuit 3
Short circuit, cylinder tem-
perature sensor or comfort
sensor
Short circuit, outlet tem-
perature sensor
Lead break, cylinder tem-
perature sensor or comfort
sensor
Lead break, outlet temper-
ature sensor
Gas pressure switch pre-
vents burner start.
Mains voltage too low
Feedback input from inter-
nal H1 extension prevents
burner start.
Temperature limiter earth
fault
Internal H1/H2 extension
earth fault
Gas pressure switch earth
fault
Troubleshooting
Measures
Check and adjust rotary selector
S1 (see page 116).
Check flow temperature sensor
(see page 117).
Check and adjust rotary selector
S1 (see page 116).
Check cylinder temperature sensor
(see page 111) or comfort sensor
(see page 113).
Check outlet temperature sensor
(see page 113)
Check cylinder temperature sensor
(see page 111) or comfort sensor
(see page 113).
Check outlet temperature sensor
(see page 113).
Check gas supply (gas pres-
■
sure).
If installed: Check gas pressure
■
switch for correct function.
If necessary, disconnect plug 111
from the control unit and check
whether the burner starts.
Check the power supply.
Check that internal H1 extension
and any devices connected to it
are correctly connected and work-
ing properly (internal: Plug 53/96
power interruption)
Check temperature limiter, con-
necting cables and plug-in connec-
tion for contact to earthed compo-
nents. Remove contact if necessa-
ry.
Press reset button R.
Check internal H1/H2 extension,
connecting cables and plug-in con-
nection for contact to earthed com-
ponents. Remove contact if neces-
sary.
Press reset button R.
Check gas pressure switch, con-
necting cables and plug-in connec-
tion for contact to earthed compo-
nents. Remove contact if necessa-
ry.
Press reset button R.
97