Viessmann Vitocrossal 300 CA3 2.5 Installation And Service Instructions Manual page 109

Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
Air Pressure Switches
1.25 MMBTU and 1.5 MMBTU
2.0 MMBTU
(continued)
Combustion chamber pressure monitoring function (LDW2)
In order to monitor the pressure in the combustion
chamber, the switching threshold of the air pressure
switch 2 (LDW2) is monitored in all operational phases
(with the exception of safety and stabilization times).
The air pressure monitor B will generate a fault
shutdown at the burner control unit in the following
situations:
If the combustion chamber pressure lies outside of the
permissible range after two attempts during the pre-
aeration phase, normal operation, or the post-purge
phase.
The fault shutdown is registered with the fault indicator
" " in the burner control unit display.
F Fb
The fault shutdown can be released by pressing the reset
button R.
Boiler model Burner model
CA3 1.25 MMBTU
2.5 and 3.0
1.5 MMBTU
CA3 1.5 MMBTU
3.5 to 6.0
2.0 MMBTU
* Equipped with a non adjustable Kromschroder valve.
Service
Setting value LDW2
3.6"w.c. (9 mbar)
3.6"w.c. (9 mbar)
3.6"w.c. (9 mbar)
preset*
109