13
• To prevent debris or creatures from entering the
combustion system, a protective screen may be
installed over the combustion air intake opening. The
screens hole size must be large enough to prevent air
restriction.
Existing Installations
When an existing furnace is removed from a vent system
serving other appliances, the existing vent system may
not be sized properly to vent the remaining appliances
(For example: water heater). An improperly sized venting
system can result in the formation of condensate, leakage,
or spillage. The existing vent system should be checked
to make sure it is in compliance with NFGC and must be
brought into compliance before installing the furnace.
NOTE: If replacing an existing furnace, it is possible you
will encounter an existing plastic venting system that is
subject to a Consumer Product Safety Commission recall.
The pipes involved in the recall are High Temperature
Plastic Vent (HTPV).
This
recall does not apply to other plastic vent pipes, such
as white PVC or CPVC. Check for details on the CPSC
website or call their toll-free number (800) 758-3688.
The method for disposing of condensate varies according
to local codes. Consult your local code or authority having
jurisdiction. Neutralizer kit P/N 902377 is available for
use with this furnace.
This furnace has multiple options for positioning the vent
pipe as described in the, Vent and Inducer Assembly
Options section (page 17). Each of the condensate
drain lines must be J-trapped using field supplied parts.
After the condensate lines are J-trapped, they may be
combined together when routed to the drain.
For Installations where there is limited clearance for the
J-Trap (such as an attic where it may be installed between
ceiling joists), either side of the J-Trap can be shortened
to a minimum of 3 Inches. See Figure 11 (page 16).
riser may be provided as shown in Figure 9 (page 12).
Insulation is required to prevent freezing of this section
of pipe. See Table 2 for vent freezing protection.
Outdoor Terminations - Vertical Venting
Termination spacing requirements from the roof and from
each other are shown in
Figure 10. The roof penetration
must be properly flashed and waterproofed with a plumbing
roof boot or equivalent flashing. Vent and combustion air
piping may be installed in an existing chimney which is
not in use provided that:
• Boththeexhaustventandairintakerunthelengthof
the chimney.
• Thetopofthechimneyissealedandweatherproofed.
• The termination clearances shown in
Figure 10 are
maintained.
• Noothergasredorfuel-burningequipmentisvented
through the chimney.
Vent Freezing Protection
CAUTION:
icing.
• Table 2 lists the maximum length of flue pipe that can
travel through an unconditioned space or an exterior
space. The total vent length must not exceed the
lengths noted in Table 1 (page 10). For Canadian
installations, please refer to the Canadian Installation
Code (CAN/CGA-B149.1 or 2) and/or local codes.
• Forextremelycoldclimatesorforconditionsofshort
furnace cycles (i.e. set back thermostat conditions)
the last 18 inches of vent pipe can be reduced. It is
acceptable to reduce from 3” to 2-1/2”, 3” to 2”, or 2”
to 1-1/2” if the total vent length is at least 15 feet in
length, and the vent length is within the parameters
specified in Table 1. The restriction should be counted
as 3 equivalent feet. Smaller vent pipes are less
susceptible to freezing, but must not be excessively
restrictive. The length of the 2 inch pipe must not be
longer than 18 inches.
• If furnace is installed horiziontally, make sure the
drainage port on the in-line drain assembly is pointed
downward to ensure proper drainage of condensate.
For GUH92A series, see Figure 37 (page 48) & Figure
38 (page 49)
. For GUH95A & GUH95C series, see
Figure 42 (page 53).
WINTER DESIGN
TEMPERATURE
MAXIMUM FLUE PIPE LENGTH (FEET)
IN UNCONDITIONED & EXTERIOR SPACES
WITHOUT INSULATION WITH INSULATION*
20 45 70
0 20 70
-20 10 60
*NOTE: Insulation thickness greater than 3/8 inch, based on an R value
of 3.5 (ft x F x hr) / (BTU x in.)
Vent Protection
To Next Page
Loading...
