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TF-SERIES INSTALLATION, OPERATION AND SERVICE MANUAL
38
9.4 Vertical Venting
For 4" (10 cm), an approved vent cap
(P/N 90502300) must be used.
For 6" (15 cm) common vent, an approved vent cap
(P/N 90502302) must be used.
A vent shall not extend less than 2' (0.6m) above the
highest point where it passes through a flat roof of a
building.
9.5 Unvented Operation Tube Termination
Turndown type vent terminal with a screen must be
installed at the exhaust end of the tube. Vent terminal
design shall not incorporate backdraft flap.
FIGURE 22: Tube Termination
9.6 Length Requirements
The maximum vent length, where both tubes are
vented together is 45’ (13.7 m) of 6" (15 cm) diameter
duct. The maximum vent length, where both tubes
are vented individually is 45’ (13.7 m) of 4" (11 cm)
diameter duct, or 22.5’ (7 m) on each tube.
The maximum outside air s
upply duct length allowed
is 45’ (13.7 m) of either 4" (10 cm) or 5" (13 cm)
diameter, however the maximum length depends on
the venting arrangement used.
The total vent length, plus outside air duct length,
plus any extensions to minimum heat exchanger
lengths, cannot exceed 65' (19.8 m).
Vent length should be limited to less than 20' (6 m). If
using vent lengths greater than 20' (6 m),
condensation will form in the vent pipe. Insulation
and additional sealing measures (high temperature
silicone at all seams) are required. Optional heat
exchanger lengths are considered as vent length for
length determination.
Subtract 15' (4.6 m) of maximum allowed vent or duct
length per vent elbow if more than two are used.
9.7 Horizontal Ventilation 4" (10 cm) Pipe
Burner
Tube
Flexible
Boot
Vent Terminal
Combustible or
Non-Combustible
Wall
Single Wall
Vent Pipe
Metalbestos
Cap
4" (10 cm) Single Wall Pipe
Vent Terminal
18" (46 cm)
Min.
Non-Combustible
Wall
Approved
Wall
Thimble
Install with boot
extended
4" (10 cm) Single Wall Pipe
SIDE VIEW
Description Part Number
Flexible Boot 91412800
Boot Clamp 91901300
Vent Terminal (Comb. Wall) 90502100
Vent Terminal 02537801-1P
Vent Sleeve 09080000