ECR International Utica Boilers MAC-115, Installation, Operation & Maintenance Manual, Page: 31 / 138

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5 - COMBUSTION AIR AND VENT PIPING
5.10 (3" / 80 mm Only) Flexible Vent System
Flexible Pipe Minimum & Maximum Vent Lengths
3” [80 mm]
Diameter Pipe
100/115/125/150 165/205
Min Max Min Max
Natalini
Exhaust
6 ft
[1.8 m]
75 ft
[22.8 m]
6 ft
[1.8 m]
50 ft
[15.2 m]
Intake
6 ft
[1.8 m]
50 ft
[15.2 m]
6 ft
[1.8 m]
50 ft
[15.2 m]
DuraVent
®
Exhaust
6 ft
[1.8 m]
82 ft
[24.9 m]
6 ft
[1.8 m]
50 ft
[15.2 m]
Intake
6 ft
[1.8 m]
50 ft
[15.2 m]
6 ft
[1.8 m]
50 ft
[15.2 m]
Centrotherm
Exhaust
6 ft
[1.8 m]
52 ft
[15.8 m]
6 ft
[1.8 m]
50 ft
[15.2 m]
Intake
6 ft
[1.8 m]
50 ft
[15.2 m]
6 ft
[1.8 m]
50 ft
[15.2 m]
Z-Dens
Exhaust
NA
6 ft
[1.8 m]
50 ft
[15.2 m]
Intake
Single Wall Elbows - Equivalent Length
3" [80 mm]
45° bend 0.82 ft [0.25 m]
90° bend 1.64 ft [0.50 m]
• Maximum vent lengths based on equivalent straight
runs only. Include rigid pipe and fittings in overall
equivalent length calculations.
• Flexible venting installations use single wall
polypropylene to pass flue gasses to base of chimney,
then flexible venting to get them to termination at the
top.
• Combustion air is not supplied through masonry
chimney. Combustion air must be from outside using 3"
[80 mm] single wall polypropylene.
• Position boiler to use minimum of rigid single wall
polypropylene venting to the chimney.
• Follow venting manufacturer's instructions on assembly
and clearances to maintain.
• Avoid sharp bends in flexible venting.
FIGURE 5-24 - (3" / 80 mm Only) Flexible Venting
System CAN BE USED ON ALL SIZES
Combustion
Air
Vent Terminal
Flexible Vent
Note
Flexible vent systems shall only be run vertical.
Horizontal runs before adapting to flexible must
be rigid pipe.
Rigid Vent
240013354 REV A [07/01/2021]