Install Instructions

17
2 Venting (continued)
Figure 2-4_Vent termination from flat roof - 10 ft. or more
from parapet wall
Figure 2-3_Vent termination from flat roof - 10 ft. or
less from parapet wall
Vent system options
Vent System Options
This fan-assisted Category 1 unit has two venting options.
1. Conventional Negative Draft Venting
This option uses a vertical rooftop flue termination.
Combustion air is supplied from the mechanical room.
See page 15 for detailed information.
2. Outdoor Installation Venting
This option uses the installation of special air inlet and
vent caps on the unit.
All units are shipped from the factory equipped for
conventional negative draft venting. All other optional vent
systems require the installation of specific vent kits and venting
materials. The following is a detailed explanation of the
installation requirements for each venting system, components
used and part numbers of vent kits for each model.
⚠ CAUTION
Units which are shut down or will not operate may experience freezing due to convective air flow in flue
pipe, through the air inlet, or from negative pressure in the equipment room. In cold climates, operate pump
continuously to help prevent freezing of boiler water. Provide proper freeze protection. See Freeze Protection,
page 48.
TABLE 2A
FLUE PIPE SIZES
MODEL FLUE SIZE MODEL FLUE SIZE
497 6'' 1257 12''
647 8'' 1437 12''
747 8'' 1797 14''
987 10'' 2067 14''
Installer may increase diameter one pipe size for ease of installation, if needed.
Installation & Service Manual
Figure 2-5_Vent system must be sealed
1/2"
VENT SYSTEM
UNIT OUTLET
DIR #2000586700 00
SEAL JOINT
(I.E., RTV SILICONE)