Viessmann Vitodens 333-F Service Instructions Manual page 79

Fault codes
(cont.)
Fault Const. weath.-
code comp.
on the
display
59 X X
A2 X
A4 X
A7 X
A8 X
System char- Cause
acteristics
No DHW heat- Outlet tem-
ing perature
sensor lead
broken
Emergency System
mode with in- pressure too
sufficient sys- low
tem pressure,
triggered by
code "0d" (see
page 49)
Control mode Max. system
pressure ex-
ceeded
Control mode Faulty pro-
as per deliv- gramming
ered condition unit
Burner Air lock in
blocked. The the internal
venting pro- circulation
gram is started pump or
automatically minimum
(see page 46) flow rate not
achieved
Troubleshooting
Measures
Check sensors
(see page 89)
Top up with water
Check system
pressure.
Check the func-
tion and sizing of
the diaphragm ex-
pansion vessel.
Vent the heating
system.
Code "0E" is set
to 1 to document
the fault. After the
fault has been re-
moved, reset
manually to 0.
Replace program-
ming unit
Vent the system if
the fault message
continues to be
displayed
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