IBC VFC 15-150 Installation And Operating Instructions Manual page 18

WARNING
When using Indoor
Air options, adequate
combustion air must be
supplied to the boiler room
according to the requirements
of all applicable codes.
1-12
VFC 15-150, VFC 45-225 MODULATING GAS BOILERS
Combustion air piping is connected at the base of the boiler using a standard 2"
PVC (ABS) coupler or elbow and run horizontally or vertically to the outdoors.
Screen material can be placed at the inlet as appropriate for the environment
(e.g. insects, dust).
For 3" piping, a 3"x 2" bushing is to be used in the inlet piping within 3 feet of
the combustion air line clearance hole at the base of the boiler. Such 3' interval
of 2" pipe can be treated as 3" pipe without reference to its smaller diameter in
calculation of the maximum allowable vent travel distance. All elbows and tees at
the base of the boiler and at the termination must be included in the calculation.
Care must be taken to ensure adequate separation is maintained between the
air intake inlet and the vent terminal. Refer to the vent terminal configuration
drawings in the Vent Termination section above.
Support should be provided for intake piping, particularly so for horizontal runs
(follow local code).
1.4.8 "Indoor Air" Combustion Air Intake Piping
An "Indoor Combustion Air installation", as described herein, is one in which air
for combustion is taken from the ambient air around the boiler.
Figure 11: Indoor air - intake, exhaust and condensate removal system
To support combustion, an ample air supply is required. This may require
direct openings in the boiler room to the outside. If the boiler is not in a
room adjacent to an outside wall, air may be ducted from outside wall
openings.
Provisions for combustion and ventilation air must be made as follows:
•
in the USA, in accordance with the National Fuel Gas Code, ANSI Z223.1
(latest edition), or applicable provisions of the local building codes
•
in Canada, in compliance with B149.1-10.
INSTALLATION AND OPERATION INSTRUCTIONS