Viessmann Vitodens 050-W Installation And Service Instructions Manual page 60

Troubleshooting
Fault messages
(cont.)
Displayed fault System characteristics
code
69 Burner in a fault state
70 Burner in a fault state
71 Burner in a fault state
72 Burner in a fault state
73 Burner in a fault state
74 Burner locked out.
Internal circulation pump off.
No central heating and no
DHW heating
75 Burner in a fault state
77 Burner in a fault state
60
Cause
Ionisation current lies out-
side the permissible range
HBMU heat management
unit internal fault
Fan speed too low
Fan idle state not reached
Internal communication
error
System pressure too low
No flow rate
HBMU heat management
unit data memory
Measures
Check ionisation electrode for the
following:
Check whether insulation block is
■
touching electrode ceramic.
Check gas solenoid valve: In the
■
service menu under "b.6", set the
burner output to the lower heat-
ing output for approx. 4 min. If
the fault occurs, replace the
HBMU heat management unit.
See chapter "Replacing the
HBMU heat management unit".
Change the burner output from
■
lower to upper heating output in
the service menu under "b.6". If
this fault occurs during modula-
tion, check the inlet strainer for
contamination. Replace the fan
unit if necessary.
Replace the HBMU heat manage-
ment unit. See chapter "Replacing
the HBMU heat management unit".
Check fan for blockage.
■
Check setting for gas type and
■
flue system.
Reset the appliance.
Reset the appliance.
■
If the fault occurs repeatedly, re-
■
place the fan unit.
Reset the appliance.
If the fault occurs repeatedly, re-
place the HBMU heat management
unit. See chapter "Replacing the
HBMU heat management unit".
Top up with water.
Vent the system.
If the fault occurs repeatedly:
Check system pressure sensor
■
with external pressure gauge.
Check diaphragm expansion
■
vessel pre-charge pressure.
Check settings for set system
■
pressure and range.
Open BDF valves.
■
Top up with water.
■
Replace the flow sensor (if instal-
■
led). Replace the pump.
Reset the appliance.
If the fault occurs repeatedly, re-
place the HBMU heat management
unit. See chapter "Replacing the
HBMU heat management unit".