Air Shutter Setting - Heatilator NNXT4236IF-B 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. It may need to be adjusted for other venting
scenarios.
• Adjust air shutter for longer vertical runs. See Figure 9.1.
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 9.1.
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 9.1 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
NNXT3933IF-B
NNXT3933ILF-B
NNXT4236IF-B
NNXT4236ILF-B
Minimum and maximum shutter settings are set up to appear like Figure 4.21.
• Minimum vent run consists of enough horizontal vent pipe to exit 2 X 6 wall construction (approximately 8 inches).
• Maximum vent run consists of "H Maximum" on Figure 4.21.
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.
48 Heatilator • NNXT4236IF-B, NNXT4236ILF-B, NNXT3933IF-B, NNXT3933ILF-B Installation Manual • 2384-980 Rev. J • 6/17
SHUTTER
MEASUREMENT
THUMBSCREW
CLOSE OPEN
GAS TYPE MINIMUM VENT RUN
NG 3/4 IN.
PROPANE 3/4 IN.
NG 3/4 IN.
PROPANE 3/4 IN.
MAXIMUM VENT RUN
3/4 IN.
3/4 IN.
3/4 IN.
3/4 IN.