Harsco Industrial C1500H Installation & Owner's Manual page 21

When combustion air is supplied from outside the building, the boiler room shall be provided with one or two openings
to ensure adequate combustion air and proper ventilation.
When using one permanent opening, the opening shall commence within 12 inches of the ceiling and shall
communicate directly with the outdoors or through a vertical or horizontal duct that communicates to the outdoors.

Minimum free area of the opening is 1 square inch for each 3000 Btu/hr (700 mm
input capacity, and
1. Not less than the sum of the areas of all vent connectors in the room.
When using two permanent openings, one opening shall commence within 12 inches above the floor and the other
within 12 inches below the ceiling, preferably on opposite walls. The openings shall communicate directly, or by way
of ducts, with free outdoor air. The minimum net free area of the openings shall be calculated in accordance with the
following:

When air is taken directly from outside the building, each opening (minimum of two, as outlined above), 1 square
inch for each 4,000 Btu per hour (550 mm

When air is taken from the outdoors through a vertical duct into the mechanical room, 1 square inch per 4,000 Btu
2
per hour (550 mm /kW) of total boiler input is required.

When air is taken from the outdoors through a horizontal duct into the mechanical room, 1 square inch per 2,000
Btu per hour (1100 mm
NOTE:
1. The required size of openings for combustion and ventilation air shall be based on the net free area of the
opening.
2. Screens shall be not smaller than ¼"
3. Motorized louvers shall be interlocked with the appliance so that they are proven open prior to main burner
ignition and operation.
Table of US Minimum area of ventilation openings per boiler (sq inches)
®
MACH Boiler
MODEL
C1500H
C2000H
C2500
C3000
C4000
3.5.2.2 Air Inlet Requirements – Canada (CAN/CSA B149.1)
A. Ventilation of the space occupied by fuel burning appliance(s) or equipment shall be supplied by a ventilation
opening at the highest practicable point communicating with the outdoors. The total cross sectional area of the
ventilation opening must be either 10% of the net free area required for combustion air or 10 sq. in. (6500 mm
whichever is greater.
B. Use the following opening calculation for MACH
When combustion air is supplied for a forced draft burner by natural airflow from the outdoors and there is no draft
regulator or draft hood in the same space, there shall be a permanent opening with a cross sectional area not less
than 1 sq. in/ 30,000 Btu/Hr (70 mm
with the ventilation air opening defined in paragraph A.
2
/kW) of total boiler input is required.
2
/kW) of total boiler input is required.
INDOOR AIR SUPPLY
SAME FLOOR DIFF FLOORS
1500 3000
2000 4000
2500 5000
3000 6000
4000 8000
2
/kW) of the total rated input to the burner(s). This opening must not interfere
AIR SOURCE
OUTDOOR AIR SUPPLY
ONE OPENING
500
667
833
1000
1334
® ®
or MODU-FIRE FD boilers:
21
®
MACH
2
/ kW) of installed appliance
TWO OPENINGS
VERT
DIRECT DUCT
375 375
500 500
625 625
750 750
1000 1000
Gas Fired Boiler
HORIZ
DUCT
750
1000
1250
1500
2000
2
),