ECR International Utica Boilers UCS 240 Installation, Operation & Maintenance Manual page 26

6.7 Twin Pipe Polypropylene and CPVC 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
Exhaust and combustion air intake are located in same
general location and are of equal length. See Figures 6-6 to
6-8.
Twin Pipe Maximum Vent Lengths (See Figure 6-6)
Intake Vent
Exhaust Vent
Combined Vent
Elbow
45°
90°
Do not count first elbow against maximum vent
Note
length.
If using indoor air for combustion do not exceed
Note
100ft (30m) exhaust vent pipe.
6 - COMBUSTION AIR AND VENT PIPING
L1 49 ft (15m)
L2 51 ft (15.5m)
L1+L2 100 ft (30.5m)
Total Length Reduction
10" (0.3 m)
2 ft (0.6 m)
FIGURE 6-5 - Two Pipe Polypropylene System Adapter
FIGURE 6-6 - Separated Horizontal Flue Termination
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Boiler
PN 240011654, Rev. J [01/31/2020]