lp-445-r4 Rev. 006 Rel. 027 Date 7.21.20
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17. Maximum Snow Level Determination: These installation
instructions reference snow levels in establishing a minimum height
for the installation of exhaust vent or air intake terminations. Snow
levels shall be determined as follows:
a. The installation location may, by ordinance, designate how snow
levels are calculated in that location; or
b. In the absence of specific ordinances, snow levels shall be calculated
from the average monthly maximum depth of snow accumulation as
indicated by the National Weather Service’s 10 year statistics for the
installation location/geographical area.
In addition:
•
Total length of vent piping shall not exceed the limits specified
in this manual.
•
The vent piping for this direct vented appliance is approved for
zero clearance to combustible construction.
•
The flue products coming from the exhaust vent will create a
large plume when the heater is in operation. Avoid venting in
areas that will affect neighboring buildings or be considered
objectionable.
•
DO NOT locate exhaust vent or intake pipe in a parking area
where machinery may damage the pipe.
•
DO NOT vent near soffit vents, crawl space vents, or other areas
where condensate or vapor could create a nuisance or hazard or
cause property damage.
•
DO NOT vent where condensate vapor could cause damage or
could be detrimental to the operation of regulators, relief valve,
or other equipment.
In the Commonwealth of Massachusetts and as Required by State
and Local Codes:
•
The vented gas fueled appliance shall not be installed so its
combustion, ventilation, or dilution air is obtained from a
bedroom or bathroom.
•
Signage: Whenever any through-the-wall (horizontal or sidewall)
vent is installed less than seven feet above the finished grade,
a metal or plastic identification plate shall be permanently
mounted to the exterior of the building at a minimum height
of eight feet above grade directly in line with the exhaust vent
terminal. The sign shall read, in print no less than 0.5 inches
in size, “GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL
OBSTRUCTIONS”.
•
Marking of Exhaust Vent and Intake Pipe: Piping used for
ventilation, make-up, or combustion air intake shall be labeled
as follows:
a. Throughout the entire developed length:
i. Labels must be placed every ten feet for exposed/visible
piping; or
ii. Labels must be placed every three feet for concealed piping.
b. At all changes of direction;
c. On each side of a penetration through a partition, wall or
ceiling; and
d. The labels shall be black lettering that:
i. Indicates that the piping is used for ventilation, make-up, or
combustion air intake, and
ii. The letters shall be sized equal to a minimum of the pipe
diameter. However, for piping with a diameter exceeding two
inches, said lettering does not need to be larger than two
inches.
H. Applications
1. Direct Vent Installation of Exhaust and Intake
If installing a direct vent option, combustion air must be drawn
from the outdoors directly into the boiler intake, and exhaust
must terminate outside. There are three basic direct vent options
detailed in this manual: 1. Side Wall Venting, 2. Roof Venting, and 3.
Unbalanced Venting.
Be sure to locate the boiler such that the exhaust vent and intake
pipe can be routed through the building and properly terminated.
Different vent terminals can be used to simplify and eliminate
multiple penetrations in the building structure (see Optional
Equipment in Venting Section). The exhaust vent and intake pipe
lengths, routing and termination methods must all comply with the
methods and limits given in the Venting section of this manual.
When installing a combustion air intake from outdoors, care must be
taken to utilize uncontaminated combustion air.
NOTE:
To prevent
combustion air contamination, see Table 1.
Take extra precaution to adequately support the weight of vent
pipes terminating through the roof. Failure to properly support
roof terminated piping could result in property damage, serious
injury, or death.
Figure 12 - Two Pipe Roof Venting
NOTE:
This drawing is meant to demonstrate system venting only.
The installer is responsible for all equipment and detailing required
by local codes.
