Function Description Air Pressure Switch; Fan Pressure Monitoring (Air Pressure Switch 1 - 131); Combustion Chamber Pressure Monitoring (Air Pressure Switch 2 - 131A); Fan For Burners 115 To 186 Kw - Viessmann Vitocrossal 200 Service Instructions For Contractors

Function description
Air pressure switch

Fan pressure monitoring (air pressure switch 1 - 131)

The switching threshold of air pressure switch 1 (131)
is monitored in all fan ramp-up phases and checked
during 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 falls outside the permissible range
during the pre-purge phase (tolerance time approx.
5 minutes).
■ If, in control mode, the air pressure switch fails or the
air pressure falls outside the permissible range.
The fault shutdown is indicated by fault codes "F F5"
and "F F7" on the burner control unit display (see
page 34). The fault shutdown can be cleared by press-
ing reset button R on the burner control unit.

Combustion chamber pressure monitoring (air pressure switch 2 - 131A)

To monitor the combustion chamber pressure, the
switching threshold of air pressure switch 2 (131A) is
monitored in all operating phases (except during safety
and stabilising time).
The air pressure switch triggers a fault shutdown of the
burner control unit under the following circumstances:
■ If the combustion chamber pressure falls outside the
permissible range in the pre-purge phase, in control
mode or in the post-purge phase after 2 attempts.
Only for multi-boiler systems with flue gas cascade:
■
Checking and monitoring of the flue gas damper
function
The fault shutdown is indicated by fault code "F FB" on
the burner control unit display (see page 34). The fault
shutdown can be cleared by pressing reset button R
on the burner control unit.

Fan for burners 115 to 186 kW

A
Fig. 46
Connector with screw
A
66
Rated heating LDW1 setting value in mbar (Pa)
output in kW
87
115
142
186
246
311
Rated heating LDW2 setting value in mbar
output in kW (kPa)
87
115
142
186
246
311
0.5 (50)
↓
1 (100)
↓
5 (0.5)
↑