Utica Boilers MGB Series II/MGC Series Installation Instruction

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8 - VENT DAMPER OPERATION
Figure 8 - Vent Damper Installation
Figure 9 - Vent Damper Placement
Annually check vent damper and all flue product 
carrying areas of appliance, with particular attention 
given to deterioration from corrosion or other 
sources.  If you see corrosion or other deterioration, 
contact your heating contractor for repairs.  Check 
vent damper operation as follows:
•  When boiler is off, check vent damper positions 
indicator points to closed position, Figure 10.
•  Turn thermostat or controller up to call for heat 
and check vent damper indicator points to open 
position.
•  Turn thermostat or controller down again and 
check damper position indicator returns to closed 
position.
Vent Damper Manual Operation
Vent damper may be placed in open position to 
permit burner operation by using “HOLD DAMPER 
OPEN” switch, located on damper controller.  
Thermostat will control burner firing as before, while 
damper will remain open.  DO NOT turn damper 
open manually or motor damage will result.  Set 
switch to “AUTOMATIC OPERATION” to close vent 
damper during burner off cycle.
For further information, and vent damper 
troubleshooting guide, refer to manual packaged with 
vent damper.
Inspect vent damper at least once a year by a 
qualified service technician.  
Figure 10 - Vent Damper Position Indicator