EMX, EMXO and EMXGO SERIES WATER BOILERS
34-503 07/13
9
12 COMBUSTION & VENTILATION AIR OPENING
Provisions for combustion and ventilation air must be in accordance with Section 5.3, Air for Combustion and
Ventilation, of the latest edition of the National Fuel Gas Code ANSI Z223.1, or applicable provisions of the
local building codes.
The equipment room must be provided with two openings to assure adequate combustion air and proper
ventilation.
1. If air is taken directly from outside the building (see Figure 1):
a. Inlet air opening, 1 square inch per 2,000 Btu/h input. This opening must be located near the floor.
b. Outlet air opening, 1 square inch per 2,000 Btu/h input. This opening must be located near the ceiling.
2. If air is taken from another interior space (see Figure 2), each opening specified above should have a
minimum free area of 1 square inch per 1,000 Btu/h input.
CONFINED AREA
FIGURE 1
Equipment located in confined spaces; all air from
outdoors
CONFINED AREA
FIGURE 2
Equipment located in confined spaces; all air from
inside the building
CAUTION: Under no circumstances should the equipment room ever be under negative pressure.
Particular care should be taken when exhaust fans, compressors, air handling units, etc. may rob air
from combustion equipment.
The combustion air supply must be completely free of any chemical fumes. Common chemicals that
must be avoided are fluorocarbons and other halogenated compounds most commonly present as
refrigerants or solvents such as freons, tri-chlorethylene, perchlorethylene, chlorine, or salts for use in
water softeners or any other heavy gas are particularly injurious and corrosive after contact with
flames or hot surfaces. The result is improper combustion and premature equipment failure.