Installation
900683-01F, 10/2018
Innovative Hearth Products
DRT3500 Series Direct-Vent Gas Fireplaces
44
Air Shutter Adjustment Guidelines
• If smoke or soot is present, first check the log set positioning to ensure that the flames are not impinging on any
of the logs. If the log set is properly positioned and a sooting condition persists, then the air shutter should be
opened more.
• The more offsets in the vent system, the wider the air shutter will need to be opened.
• An fireplace operated with the air shutter opened too far may have flames that appear blue and transparent.
These weak, blue, and transparent flames are termed anemic.
• Propane models may exhibit flames that candle or appear stringy. If this condition is present and persists, adjust
the air shutter to a more closed position, then operate the fireplace for a few more minutes to ensure that the
flame normalizes and the flames do not appear sooty. The following chart is provided to help achieve the correct
air shutter adjustment for your installation.
Table 2 - Air Shutter Adjustment Guidelines
Amount of Primary
Air
Flame Color
Air Shutter Adjustment
If air shutter is
closed too far
Flame will
be orange
Air shutter gap should be increased
If air shutter is
open too far
Flame will
be blue
Air shutter gap should be decreased
Air Shutter
Adjustment
Rod Down
(Fully-Open
Position)
Burner
Tube
Adjustment
Rod Up
(Fully-Closed
Position)
Adjustment
Set-Screw
Figure 1 - Air Shutter Adjustment Rod
1. Move the adjustment rod down to increase air flow and up to decrease it. The rod is located in the lower control
compartment. Position the air shutter to the factory setting (Table 29).
2. Light the fireplace. Follow the lighting procedure on the lighting label in the control compartment or Pages 66-67.
3. Allow the burner to operate for at least fifteen (15) minutes while observing the flame continuously to ensure that
the proper flame appearance is achieved (Figure 35). If the following conditions are present, adjust accordingly.
• If flame appears weak or sooty, adjust the air shutter, incrementally, to a more open position until the proper
flame appearance is achieved.
• If flame remains blue, adjust the air shutter, incrementally, to a more closed position until the proper flame
appearance is achieved.
4. When satisfied that the burner flame appearance is normal, reinstall the lower control compartment door, then
proceed to finish the installation.
Figure 35 - Burner Flame Appearance
Table 29 - Main Burner Shutter Opening—Factory Setting
Models
Natural Gas
Propane
All
1/16”
(1.6 mm)
1/8”
(3.2 mm)
Traditional - Charred Oak Logs
