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5790 733 - 07
Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
1. Open gas shut-off valve.
2. Check the rotary damper setting when burners are off.
The rotary damper windows
B
must be fully opened.
The scale ring
D
must be set at “0” on the air damper
actuator relative to the marking
C
.
3. Check whether the compensating tubing
A
has been
connected between the gas valve and Venturi mixing
pipe.
4. Put burners into operation.
5. Check the setting of the rotary damper during the start-
up phase. The rotary damper windows
B
must nearly
close for approx. 5 sec. The scale ring
D
must be set
as follows during this time:
Service
Checking the Rotary Damper Setting
Boiler model Burner model
Rotary damper setting
2.5 and 3.0
1.25 MMBTU
Not equipped
1.5 MMBTU
Not equipped
3.5 to 6.0
1.5 MMBTU
20° (close) 0° open
2.0 MMBTU
20° (close) 0° open
Checking the functioning of the burner damper
Angle position of the switch cams: The servomotor is at
setting “0” during standstill. The factory-installed settings
may not be changed.
Putting burners into operation
Servomotor moves to 105°, levers and rods move to the
left. Valve
A
is opened.
Turning burners off
Servomotor moves to setting “0”, valve
B
is closed.
The spring on the rod is compressed approx 0.08 in. to
0.21 in. (2 to 3 mm).
The valve is thus pressed against the facings.
The tightness is ensured.
Checking the Burner Damper Setting
