Functions Air Pressure Switch; Fan Pressure Monitoring (Ldw1) - Viessmann MatriX Service Instructions For Contractors

Functions
Air pressure switch

Fan pressure monitoring (LDW1)

A B
Fig. 32
A Reset button R
Air pressure switch 2
B
42
The switching threshold of air pressure switch 1
(LDW1) is monitored in all fan ramp-up phases and
checked in modulating burner operation. This ensures
a minimum pre-purge.
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 permissible range
during the pre-purge phase (tolerance time approx. 5
minutes)
■ 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. See
chapter "Display and programming unit" on page 29.
Rated heat- Rated heat in-
ing output put
P Q (H ) [net
max max i
(50/30 °C) cv]
in kW
400
500
630
LDW1 setting value
in kW in mbar (kPa)
381
474 2 (0.2)
593
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