17
Twin Pipe Vent Lengths
(Includes first elbow and termination)
Boiler Size
125/150
Vent Size
3"
[80 mm]
2"
[50 mm]
All
Maximum
Minimum
Intake Vent
L1
49 ft [15m]
85 ft
[25.9 m]
6 ft
[1.8 m]
Exhaust Vent
L2
147 ft [45 m]
Combined
Vent
L1+L2
196 ft [60 m]
170 ft
[51.8 m]
12 ft.
[3.6m]
Single Wall Elbows - Equivalent Length
3"
2"
45° bend
0.82 ft [0.25 m]
3 ft [0.91 m]
90° bend
1.64 ft [0.50 m]
5 ft [1.5 m]
NOTE: Two pipe can be installed horizontally or vertically.
FIGURE 5-8 - 3"/ 80 mm Twin Pipe Separated
Horizontal Flue Termination
5.8 Twin Pipe Systems
Twin pipe venting allows exhaust flue and intake flue to be
separated from each other. Fresh air is drawn in at a different
area from the flue terminal location.
A.
Twin Pipe CPVC System
CPVC is approved for boiler exhaust. CPVC or PVC are both
approved for air intake.
To transition from Coaxial at the top of the boiler to Twin Pipe
CPVC/PVC, adapter kit is available.
B.
Twin Pipe Polypropylene System
Single wall polypropylene is used for both exhaust and air
intake piping.
To transition from Coaxial at the top of the boiler to Twin Pipe
polypropylene venting an adapter kit is available.
C.
Twin Pipe Separated Flue
Exhaust and combustion air intake are not located in same
general location.
D.
Twin Pipe - Common Atmospheric Zone
Termination
Exhaust and combustion air intake are located in same
general location and are of equal length.
FIGURE 5-9 - 3" / 80 mm Twin Pipe Separated
Horizontal Flue Termination -
This
Termination
can be used
on
3"/ 80 mm
vent
only
FIGURE 5-10 - 2" / 50 mm & 3" / 80 mm Twin Pipe
Separated Horizontal Flue Termination With Tee On
Exhaust CAN BE USED ON ALL SIZES
Grade, Snow
& Ice
Maintain 12"(305 mm) US, 18"(457 mm)
Canada clearance above highest anticipated
snow level, 24" (610 mm) above roof.
Avoid locations where snow may drift and
block vent and combustion air. Ice or snow
may cause boiler to shut down if vent or
combustion air becomes obstructed.
5 - COMBUSTION AIR AND VENT PIPING
WARNING
Asphyxiation hazard! Improper installation could
result in death or serious injury. Read Twin Pipe
Installation Instructions completely and understand all
requirements before beginning installation.
!
This
Termination
can be used
on
3"/ 80 mm
vent
only
This
Termination
can be used on
2" / 50 mm &
3"/ 80 mm
vent only
240012564 REV A, [05/15/2019]