Tjernlund PAI-3,4,5,6,7 Commercial Combustion Air In-Forcer 8504036 Rev A 05/01 - Manual (Page 4)

IN-FORCER APPLICATION AND SELECTION TABLE
Verify that the total BTU/hr input of the heating appliance(s) falls within the range specified below. Check maximum duct length and
appropriate duct diameter with the IN-FORCER Selection Table below.
ECIFIN-FORCER SELECTION TABLE
IN-FORCER SELECTION TABLE
MAX. DUCT LENGTH IN EQUIV. FEET indicates how much duct may be used at the given diameter based on the four types of heating equipment.
All duct before and after the IN-FORCER must be added. To calculate equivalent duct length, add the straight duct plus 10’ for every 90
0 elbow and 5’
for each 45 0 elbow. Values in the chart assume rigid metal duct. Consult flex duct manufacturer for de-rating percentage if using flex duct. The resis-
tance for any combination of ducts and diffusers cannot exceed the maximum equivalent duct length shown in selection table.
If interlocking IN-FORCER with more than one appliance of the same type, add the BTU/HR. input of each appliance to determine IN-FORCER model
and maximum equivalent duct length and diameter. If interlocking IN-FORCER with different types of equipment consult Tjernlund Technical Customer
Service @ 1-800-255-4208 for further information.
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