(4) When the check of drainage is complete, open the check pin (CHK)
and remount the insulator and drain cap onto the drain inspection port.
Air Flow (ft.
Air Flow (ft.
Air Flow (ft.
Air Flow (ft.
7.3
21.8
7.3
21.8
7.3
21.8
7.3
21.8
(1) Remove 4 screws on the electrical component box and
remove the cover plate.
(2) Disconnect the fan motor sockets in the box.
(3) Take out the booster cable (sockets at both ends)
clamped in the box.
(4) Securely connect the booster cable sockets between the
disconnected fan motor sockets in step 2 as shown in
Fig. 3-75.
(5) Place the cable neatly in the box and reinstall the cover
plate.
Fig. 3-75
Fig. 3-76
How to read the diagram
The vertical axis is the external static pressure (psi,
in.Aq) while the horizontal axis represents the air flow
(ft.
3
/minute). The characteristic curves for “HT,” “H,” “M”
and “L” fan speed control are shown. The nameplate
values are shown based on the “H” air flow. For the 24
type, the air flow is 635 ft.
3
/minute, while the external
static pressure is 7.1 × 10
-3
psi at “H” position. If exter-
nal static pressure is too great (due to long extension of
ducts, for example), the air flow volume may drop too
low at each air outlet. This problem may be solved by
increasing the fan speed as explained above.
3-18. Increasing the Fan Speed
If external static pressure is too great (due to long extension of ducts, for
example), the air flow volume may drop too low at each air outlet. This problem
may be solved by increasing the fan speed using the following procedure:
