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Variable
Frequency
Drive (VFD)
The VFD varies the frequency
of the AC voltage
supplied
to the
indoor
fan. (See Fig. 20 and Table 23.)
This causes the variance
in
the speed of the fan. The commanded
fan speed is received
by the
VFD from the AUXI
board as a 2-10vdc
signal.
The AII DIP switch must be in the off (or towards
"U") position
to
properly
read the analog signal.
There are three jumper
wires that
must remain
installed
for proper
operation.
The VFD is mounted
behind
the fan housing
on the fan sled and the remote
keypad
is
mounted
on the front of the fan housing
for easy access.
The VFD
is factory set to the auto mode for unit operation.
....
_i2V]iii
i..........
Fig. 20 - Variable
Frequency
Drive
(VFD)
Table 23 -- VFD Connections
TERMINAL
TERMINAL
DISPLAY NAME
POINT DESCRIPTION
TYPE OF I/O
NUMBER
NAME
LOW VOLTAGE INPUTS
Shielded Cable Ground
Shield
1
SCR
ESPD
Commanded
Fan Speed
2-10vdc
2
All *
Analog Input 1 Common
Ground
3
AGND
Low Voltage Power (jumped to DI1 & DI4)
24v
10
24v
Low Voltage Common
(jumped to DCOM)
Ground
11
GND
Discrete Inputs Common (jumped from GND)
Ground
12
DCOM
Discrete Input 1 (jumped from 24v)
Switch Input
13
DI1
Discrete Input 4 (jumped from 24v)
Switch Input
16
DI4
HIGH VOLTAGE
Voltage Leg from IFC-21
Voltage Input
U1
MAINS
Voltage Leg from IFC-22
Voltage Input
V1
MAINS
Voltage Leg from IFC-23
Voltage Input
Wl
MAINS
Voltage Leg to IFM-3
Voltage Output
U2
MOTOR
Voltage Leg to IFM-2
Voltage Output
V2
MOTOR
Voltage Leg to IFM-1
Voltage Output
W2
MOTOR
Requires
the All
dip switch
to be in in the Off (or towards
"U")
position.
C09146
53
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Troubleshooting
