GE 49-80388 12-05 JR - Manual (Page 21)

21
Installation Instructions
EXHAUST BLOWER SAFETY WARNING
Sufficient air is needed for proper combustion and exhausting of gases through the flue
(chimney) of other fuel burning equipment to prevent back drafting. Follow the heating
equipment manufacturer’s guidelines and safety standards such as those published by
the National Fire Protection Association (NFPA), the American Society for Heating,
Refrigeration and Air Conditioning Engineers (ASHRAE) and local code authorities.
NOTE: The exhaust blower output is approximately 400 CFM (cubic feet per minute)
without ductwork. Each installation is different and ductwork affects blower output
accordingly. Actual blower exhaust CFM can be approximated using the graph below.
Step 1: Calculate the “equivalent duct length” using the “DUCTWORK
CALCULATIONS” table in these instructions for your installation.
Step 2: Find the approximate intersection point of the blower exhaust performance
curve with the equivalent duct length to estimate the actual maximum blower
output for your installation.
Examples: 50 equivalent feet of ductwork has approximately 320 CFM.
100 equivalent feet of ductwork has approximately 265 CFM.
Downdraft Cooktop Exhaust Blower CFM
Air Flow (CFM)
6” Diameter Equivalent Duct Length
450
400
350
300
250
200
150
100
50
0
0 25 50 75 100 125 150
EXHAUST BLOWER RATINGS