Ignition Unit - Viessmann Vitocrossal 300 CA3 2.5 Installation And Service Instructions Manual

Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
Air Pressure Switches
Legend
A Air pressure switch, fan (LDW1, compensation line on
connector marked "-")
B Air pressure switch, combustion chamber (LDW2,
compensation line on connector marked "+")
C Air pressure switch LDW2, for burner model 2000 MBH
(Compensation line on connector marked "+")

Ignition Unit

(continued)
1. Undo 2 mounting screws. Torque when installing:
9 lb.in (1 Nm)
2. Remove the display and programming unit from the
burner control unit.
3. Pull connector aCA (LDW1) and connector aCAA (LDW2)
from the plug-in strip on the burner control unit.
4. Pull compensation hose from connector.
5. Undo the mounting screw(s) on the air pressure switch.
Remove the air pressure switch cover.
Torque when installing: 9 lb.in (1 Nm).
6. Undo the base mounting screws and remove the base.
7. Install new air pressure switch in reverse order.
Observe torque settings.
Note: Attach the connection hose to the corresponding
connector.
8. For further steps, see chapter "Further assembly"
on page 117.
Note: Set the new air pressure switch to exactly the same
value as that of the replaced air pressure switch.
Air pressure switch settings
Boiler model CA3 2.5 and 3.0
Burner model 1.25
MMBTU
LDW1 mbar 1
("w.c.) (0.4)
LDW2 mbar 9
("w.c.) (3.6)
All gas pressure switches are Dungs unless otherwise noted.
* Equipped with a non adjustable Kromschroder valve.
1. Pull the connecting cable from the ignition unit.
2. Pull the ignition cables from the ignition unit.
3. Undo the ignition unit mounting screws. Remove the
ignition unit.
4. Install new ignition unit in reverse order.
Torque for mounting screws: 13 lb.in (1.5 Nm).
5. For further steps, see chapter "Further assembly"
on page 117.
Service
CA3 3.5 to 6.0
1.5 1.5 2.0
MMBTU MMBTU MMBTU
1 1 1
(0.4) (0.4) (0.4)
9 9
preset*
(3.6) (3.6)
Only for Dungs gas
pressure switches.
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