HTP EL-110, Installation Manual

Page: 49 / 97

49
M. INDOOR COMBUSTION AIR INSTALLATION IN CONFINED OR UNCONFINED SPACE
NOTE: This installation is intended for commercial
applications. For residential applications, it is
recommended to pipe intake combustion air from
the outdoors.
This boiler requires fresh, uncontaminated air for
safe operation and must be installed in a
mechanical room where there is adequate
combustion and ventilating air.
NOTE: To prevent
combustion air contamination, see Table 3.
Combustion air from the indoor space can be used
if the space has adequate area or when air is
provided through a duct or louver to supply
sufficient combustion air based on the boiler input.
Never obstruct the supply of combustion air to
the boiler.
If the boiler is installed in areas where
indoor air is contaminated (see Table 3) it is
imperative that the boiler be installed as direct vent
so that all combustion air is taken directly from the
outdoors into the boiler intake connection.
Unconfined space is space with volume not less
than 50 cubic feet per 1,000 Btu/hour (4.8 cubic
meters per kW) of the total input rating of all fuel-
burning boilers installed in that space. Rooms
connected directly to this space, through openings
not furnished with doors, are considered part of the
space.
Confined space is space with volume less than 50
cubic feet per 1,000 Btu/hour (4.8 cubic meters per
kW) of the total input rating of all fuel-burning
boilers installed in that space. Rooms connected
directly to this space, through openings not furnished with doors, are considered part of the space.
When drawing combustion air from inside a conventionally constructed building to a confined space located on
the same story, su
ch space should be provided with two permanent openings: one located 6” (15 cm) below the
space ceiling, the other 6” (15cm) above the space floor. Each opening should have a free area of one square
inch per 1,000 Btu/hr (22cm
2
/kW) of the total input of all boilers in the space, but not less than 100 square inches
(645cm
2
).
When drawing combustion air from inside a conventionally constructed building to a confined space located on
different stories, such spaces should be considered as communicating spaces when connected with one or more
permanent openings in doors or floors having a total minimum free area of two square inches per 1,000 Btu/hr
(22cm
2
/kW) of the total input of all boilers in the space, but not less than 200 square inches (645cm
2
).
If the confined space is within a building of tight construction, air for combustion must be obtained from the
outdoors as outlined in the Venting section of this manual.
Figure 20
– LP-387-Z