10
MorrHeat - Most Heat In The Industry - Rev 3/18/2019
Boiler Room Air Requirment
WARNING
Failure to provide an adequate supply of fresh air for combustion will result in
hazardous operating conditions. Do not use an exhaust fan in the boiler room.
1. To ensure safe, efficient operation, the boiler system must be supplied with sufficient air for
combustion and ventilation. (See Fig. 2)
2. Unless properly controlled, avoid the use of forced ventilation, since it can create an undesirable
pressure differential between boiler room and air source.
3. All boilers located in confined rooms should have free access to ventilation and combustion air
from two permanent opening. One opening should terminate within 12" of the ceiling , the other 12"
of the floor. Each opening shall have at least 1 sq. inch free area per 1,000 btn/hr. of burner input.
Opening should freely connect with areas having adequate infiltration of outside air.
When air comes directly from outdoors, again use two openings as explained above, except:
•
Direct connection or vertical ducting allow 1 sq. inch per 4,000 btu/hr.
•
Direct connection through horizontal ducting allow 1 sq. inch per 2,000 btu/hr.
• All ducting shall be the same size as opening but no less than 3 x 3 or 9 sq. inches.
Remember to compensate for louver blockage when calculating free air. Refer to the manufacturer's
instructions or use the general guild:
WOOD LOUVERS allow 20-25% free air, METAL LOUVERS or GRILLES allow 60%-70% free air. Any
louvers dampers should lock open or interlock with the burner to open autiomatically when the
boiler operates.
FIG. 2 | RECOMMENDED BOILER ROOM VENTILATION & COMBUSTION AIR
Chimney
Boiler
12"
12"
Louvered Openings
For Ventilation &
Combustion Air
