Viessmann Vitocrossal 300 Service Instructions For Contractors page 20

Functions
Air pressure switch
Fan pressure monitoring (LDW1)
A B
Fig. 10
A Reset button R
Air pressure switch 1
B
The switching threshold of air pressure switch 1
(LDW1) is monitored in the fan ramp-up phases and
checked in modulating burner operation. This ensures
a minimum pre-purge.
20
The air pressure switch triggers a fault shutdown of the
burner control unit under the following circumstances:
■ If the static pressure check was unsuccessful after
approx. 5 minutes
■ If the air pressure is outside the permiss. range in
the pre-purge phase (tolerance time approx. 5 min.)
If the air pressure switch fails in control mode or the
■
air pressure lies outside the permissible range
The fault shutdown is indicated by fault codes "F F5"
and "F F7" on the burner control unit display. Reset
the burner control unit by pressing reset button R.
"MatriX cylinder burner" service instructions
Rated heat- Rated heat in-
ing output put
P Q (H )
max max i
(50/30 °C) [net cv]
in kW
400
500
630
LDW1 setting value
in kW in mbar (kPa)
381
474 2 (0.2)
593
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