Twin Pipe Systems - UTICA BOILERS MAH-125 Installation, Operation And Maintenance Manual

6.8 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 a 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
Twin Pipe Maximum Vent Lengths
Intake Vent L1
Exhaust Vent L2
Combined Vent L1+L2
Single Wall Elbows - Equivalent Length
3"
45° bend 0.82 ft [0.25 m]
90° bend 1.64 ft [0.50 m]
NOTE: Two pipe separated flue can run horizontal or vertical.
6 - COMBUSTION AIR AND VENT PIPING
125/150 165/205
3" [80 mm] 3" [80 mm] 2" [ 50 mm]
49 ft 100 ft
51 ft 100 ft
100 ft 200 ft
2"
3 ft [0.91m]
5 ft [1.5 m]
FIGURE 6-7 - Twin Pipe Separated Horizontal Flue
Termination
FIGURE 6-8 - Twin Pipe on Roof Combustion Air On
Sidewall
Combustion Air
85 ft
85 ft
170 ft
FIGURE 6-9 - Twin Pipe Flue On Sidewall, Combustion
Air On Roof
Vent - T Terminal
Anticipated Snow Line
26
Vent Terminal
Ground
Level
Combustion Air
12" (305mm)
240011941 REV B, [03/31/2018]