Air Shutter Setting - Heatilator NBV30-IFT Installation Manual

E. Air Shutter Setting
Air shutter setting should be adjusted by a qualified
installer at the time of installation.
• The air shutter is set at the factory for minimum vertical
vent run.
• Adjust air shutter for longer vertical runs. See
Figure 10.1.
• Turn the thumbscrew to open or close the air shutter. It
may be necessary to use a pliers or crescent wrench to
adjust the shutter. See chart below for correct shutter
settings. The shutter measurement is taken from the
bottom of the tub to the bottom of the thumbscrew. See
Figure 10.1.
Note: Adjust air shutter after flame has reached full
maturity (approximately 20-40 minutes).
CAUTION! Risk of Burns! Components are HOT. Wear
protective gloves when adjusting shutter.
SHUTTER SPRING
Figure 10.1 Adjusting Air Shutter
Note: The air shutter is equipped with a compression
spring that helps to maintain the shutter position during
transportation. It may be necessary to relieve this spring
pressure on the thumb screw to adjust the shutter.
Air Shutter Settings (Factory Set to Minimum Vent Run)
MODEL GAS TYPE
NG
NBV30-IFT
PROPANE
NG
NBV33-IFT
PROPANE
NG
NBV36-IFT
PROPANE
NG
NBV42-IFT
PROPANE
Note: All vent runs may need to be evaluated for ideal shutter
settings. Shutter distances may vary due to vent run, fuel quality,
and elevation.
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Heatilator • NBV30-IFT, NBV33-IFT, NBV36-IFT, NBV42-IFT Installation Manual • 2624-980 Rev. E • 10/20
SHUTTER
MEASUREMENT
THUMBSCREW
CLOSE OPEN
SHUTTER MEASUREMENT
1-3/8 IN.
1-3/8 IN.
1-3/8 IN.
1-1/4 IN.
1-1/4 IN.
1 IN.
1-1/8 IN.
1-1/8 IN.