Installation
900683-01F, 10/2018
Innovative Hearth Products
DRT3500 Series Direct-Vent Gas Fireplaces
15
MINIMUM CLEARANCES TO COMBUSTIBLES
Fireplace And Vent Clearances
The fireplace is approved with zero clearance to combustible materials on all sides (Table 8), with the following
exception: The unit may not be recessed (allowance made for mantel legs / side trim in Figure 5, Page 16). When
the unit is installed with one side flush with a wall, the wall on the other side of the unit must not extend beyond the
front edge of the unit (Figure 5).
Table 8 - Minimum Clearances *
Back ***
1-1/2” (38mm) to wrapper
0” (0 mm) to Spacers
Sides
1/2” (13 mm) to wrapper
0” (0 mm) to Spacers **
Top Standoffs
0” (0 mm) to top standoffs
Floor
0” (0 mm)
From Bottom of Unit to Ceiling
64” (1626 mm)
Vent
3” (77 mm)—Top *
1” (26 mm)—Sides and Bottom
Front Service Clearance—
clearance immediately in front of viewing area(s)
36” (914 mm)
* 3” (77 mm) above any horizontal/inclined vent component.
** See Page 21 for clearance requirements to the nailing flange located at each side of the unit and any screw heads adjacent to it.
*** When in top vent mode; no combustible material shall be allowed to contact the rear flue cap/cover.
The fireplace must be mounted on a fully supported base extending the full width and depth of the unit. The fireplace
may be located on or near conventional construction materials. However, if installed on combustible materials, such
as carpeting, vinyl tile or other combustible material other than wood flooring, the appliance shall be installed on a
metal or wood panel extending the full width and depth of the appliance.
Hearth Extension
A hearth extension is not required with this fireplace. If a hearth extension is used, do not block the lower control
compartment door. Any hearth extension used is for appearance only and does not have to conform to standard
hearth extension installation requirements.
Shelf Height
To provide for the lowest possible shelf surface, use the rear vent model. For top vent models, the venting attached
to the top vent should be routed in a way to minimize obstructions to the space above the fireplace. Do not insulate
the space between the fireplace and the area above it (Table 9). The minimum height from the base of the fireplace to
the underside of combustible materials used to construct a utility shelf in this fashion is shown in Table 9.
Table 9 - Combustible Shelf Height—Top Vent
Model
Top Vent with one 90° Elbow
Alternative Rear Vent
applications
Secure Vent
®
(using rigid elbow)
Secure Flex
®
(using flex elbow)
Secure Vent
®
35” Models
47” (1194 mm)*
49” (1245 mm)*
41” (1042 mm)**
40” Models
52” (1321 mm)*
54” (1372 mm)*
46” (1169 mm)**
45” Models
52” (1321 mm)*
54” (1372 mm)*
46” (1169 mm)**
Shelf Height
(see table)
No com-
bustibles or
insulation in
the shaded
area between
the appliance
and the shelf
above it.
* Includes 3” clearance to combustibles (required above vent components)
** In alternative, Rear Vent applications, Top Vent will be sealed as detailed in Installation
Sequence Step 4 (Page 20).
