LAARS Mighty Therm HH (Sizes 2000-5000) - Installation, Operation and Maintenance Instructions - Manual (Page 6)

LAARS Heating Systems
Page 6
NOTE: In Canada (Table 3 does not apply)
consult local building and safety codes or, in the
absence of such requirements, follow CGA
requirement, and/or CAN1-B149 standard.
3. Exhaust Fans or Vents: Any equipment which
exhausts air from the boiler room can deplete the
combustion air supply or reverse the natural draft
action of the venting system. This could cause
flue products to accumulate in the boiler room.
Additional air must be supplied to compensate
for such exhaust. The information in Table 3 is
not applicable in installations where exhaust fans
or blowers of any type are used. Such
installations must be designed by qualified
engineers.
4. If a blower or fan is used to supply air to the
boiler room, the installer should make sure it
does not create drafts which could cause
nuisance shutdowns of the pilot. If a blower is
necessary to provide adequate combustion air to
the boiler, a suitable switch or equivalent must
be wired into the boiler control circuit to prevent
the boiler from firing unless the blower is
operating.
5. The boiler must be completely isolated and
protected from any source of corrosive chemical
fumes such as emitted by trichlorethylene,
perchlorethylene, chlorine, etc.
Indoor Each Opening*
Size (Square Inches)
2000 500
2450 613
3050 763
3500 875
4050 1013
4500 1125
5000 1250
Net Free Area in Square Inches*
*Area indicated is for one of two openings;
one at floor level and one at the ceiling, so
the total net free area would be double the
figures indicated. For all other conditions,
refer to latest edition of ANSI Bulletin
Z223.1.
NOTE: Check with louver manufacturers for Net Free
Area of louvers. Correct for screen resistance to the
Net Free Area if a screen is installed. Check all local
codes applicable to combustion air.
must be laid with ends unsealed, and joints matched
in such a way as to provide a free circulation of air
from side to side through the masonry (see Figure 4).
2B. Installation of Indoor Boilers
2B-1. Combustion Air Supply
1. The boiler location must provide sufficient air
supply for proper combustion, and ventilation
of the surrounding area as outlined in the latest
edition of ANSI standard Z223.1, and/or in
Canada CAN1-B149 requirement, and any local
codes that may be applicable. Inadequate
combustion air supply may result in incomplete
combustion and consequent sooting of the heat
exchanger and unsafe operation of the boiler.
2. In general, in the U.S., these requirements
specify that boiler rooms, which represent
confined spaces, should be provided with two
permanent air supply openings communicating
directly through the wall to outside air; one
within 12 inches of the ceiling, the other within
12 inches of the floor. Each opening should
have a minimum free area of one square inch
per 4,000 BTUs/H input rating of all appliances
in the enclosed area. See Table 3 for
recommended air supply for each model. An
improperly ventilated equipment room can get
excessively hot and cause accelerated
deterioration of controls and electrical
components.
Base Must Extend Out
Min. 12" On All Sides
Of Heater Frame Metal Plate 20
Ga. Min.
Under Entire
Heater
Concrete Blocks Or Tile
Min. 7" High With 3" Min.
Air Openings
Blocks must provide solid base and be braced so
they cannot slip out of place. Air openings in blocks
must be arranged to provide unobstructed opening
through entire width or length of base.
Figure 4. Non-combustible Base. Table 3. Minimum Recomended
Air Supply To Boiler Room.