UTICA BOILERS MAHF-125 Installation, Operation & Maintenance Manual page 19

12" (305 mm) Min. horizontal separation

between combustion air intake and vent of
same appliance.
 12" (305 mm) Min. 84" (2.2 m) Max. vertical
separation between combustion air intake and
vent of different appliances.
 15" (381 mm) Max. horizontal length of vent.
Roof
 Min. vent/intake between different appliances
Terminations 12" (305 mm).
 Max. allowable total vertical vent length with
outside exposure is 10 ft.(3.05 m).
 Abandoned unused masonry chimney may
be used as chaseway for combustion air and
vent. Both combustion air and vent pipe must
exit above top of chimney with clearances as
shown in Figure 5-14.
FIGURE 5-12 - Twin Pipe on Roof Combustion Air On
Sidewall CAN BE USED ON ALL SIZES
Vent Terminal
Combustion Air
Ground
Level
FIGURE 5-13 - Twin Pipe Flue On Sidewall,
Combustion Air On Roof CAN BE USED ON ALL SIZES
Combustion Air
Vent - T Terminal
12" (305 mm)
Anticipated Snow Line
5 - COMBUSTION AIR AND VENT PIPING
FIGURE 5-14 - (2" / 50 mm & 3" / 80 mm) Twin Pipe
Roof Vent CAN BE USED ON ALL SIZES
12" (305 mm) Min.
Vent
12" (305 mm) US,
18" (458 mm) Canada Min.
Above
Anticipated Snow Line
FIGURE 5-15 - (3" / 80 mm ONLY) Single Wall
Exhaust Kit and Air Intake Minimum Distance Center
to Center
This
termination
used on
3"/ 80 mm
vent pipe
only
See Grade,
Snow & Ice
FIGURE 5-16 - (3" / 80 mm ONLY) Horizontal Twin
Pipe, Exhaust and Intake
This
termination
used on
Minimum Separation
3"/ 80 mm
vent pipe
only
See Grade,
Snow & Ice
19
15"
(381 mm)
Max.
Roof Line
Combustion
Air
43/4"
[120 mm]
12" (305 mm)
Manufacturer
Recommends
Greater Separation
240012565 REV A, [05/15/2019]