– I-70 –
1-9
Indoor Fan Performance
Concealed Duct Type
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:
(1)
Remove 2 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 the Fig. 1-1.
(5)
Place the cable neatly in the box and reinstall the
cover plate.
Booster cable
Booster cable
Electrical component box
(At shipment)
(Connected booster cable)
1743_M_I
Fan motor socket
Fan
motor
Fig. 1-1
Indoor Fan Performance
20
Air Flow Volume (m
3
/minute)
External Static Pressure
0
50
0
5
10
15
150
10
Limit line
Limit line
HT
H
L
100
1746_U_I
M
(mmAq)
(Pa)
30
40
Air Flow Volume (m
3
/minute)
External Static Pressure
0
50
0
5
10
15
150
20
Limit line
Limit line
L
100
1748_U_I
M
H
(mmAq)
(Pa)
HT
30
Air Flow Volume (m
3
/minute)
External Static Pressure
0
50
0
5
10
15
150
20
Limit line
HT
L
100
1747_U_I
M
H
Limit line
(mmAq)
(Pa)
HT : Using the booster cable
H : At shipment
NOTE
AD425CW
AD436CW AD448CW
Fig. 1-2
■
How to read the diagram
The vertical axis is the external static pressure (Pa) while the horizontal axis represents the AIR FLOW (m
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 25 type, the air flow is 18 m
3
/minute, while the
external static pressure is 49 Pa at “H” position. If external static pressure is too great (due to long extension of duct, 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.
