5370597-JIM-D-1019
Johnson Controls Ducted Systems
29
the assembly. Field installed Motorized Outdoor Damper
accessories include complete instructions for installation.
Economizer
The Economizer can be a factory installed option or a field
installed accessory. If factory installed, refer to the instructions
included with the outdoor air hood to complete the assembly.
Field installed Economizer accessories include complete
instructions for installation.
There are two Economizer options:
1.
Down Flow, End Return Horizontal applications which
include Fresh Air Hood, Exhaust Hood with Barometric
Relief.
2.
Horizontal Flow application (Field Installed Kit Only) that
requires the purchase of a barometric relief hood.
NOTE:
With the Down Flow, End Return Horizontal application
it is required to save the two Side Panels for the
economizer hood tops (See Figure 18).
Power Exhaust
The Power Exhaust can be a factory installed option or a field
installed accessory. If factory installed, refer to the instructions
included with the outdoor air hood to complete the assembly.
Field installed Power Exhaust accessories include complete
instructions for installation.
The Power Exhaust factory installed option is for Down Flow
application only.
There are two field installed Power Exhaust accessories:
1.
Down Flow application.
2.
Horizontal Flow application that requires the purchase of a
barometric relief hood.
Rain Hood
All of the hood components, including the filters, the gasketing
and the hardware for assembling, are packaged and located
between the condenser coil section and the main unit cabinet, if
the unit has factory installed options. If field installed
accessories are being installed all parts necessary for the
installation comes in the accessory.
Factory-installed VFD (Standard)
The factory-installed VFD is mounted in the blower access
compartment. The drive comes wired from the factory to include
both 3-phase power and control connections (run permit signal,
speed reference signal & fault signal). All required drive
parameters are pre-programmed at the factory, except in the
case of 208-volt applications, in which the parameter that
defines motor nameplate voltage must be changed to a value of
208.00 and the parameter that defines motor-rated current must
be changed to the appropriate value appearing on the motor's
nameplate. Refer to the enclosed drive material for instructions
on changing parameter settings.
Manual Bypass
An optional, factory-installed manual bypass switch available
with factory-installed VFD can be found in the Blower Motor
Access compartment and has the following three positions:
•
DRIVE
- routes power through the VFD for modulating
control of the indoor blower motor.
•
LINE (or BYPASS)
- routes power directly to the motor
which provides full-speed motor operation and complete
electrical isolation of the drive.
•
TEST
- routes power to the VFD but not to the motor to
allow for drive programming and/or diagnostics.
If a drive failure occurs, the unit does not automatically switch to
bypass mode. The LINE/DRIVE/TEST switch must be manually
switched to the LINE (BYPASS) position. If there is a call for the
fan, the indoor blower motor will run at full-speed while in the
bypass mode.
Figure 24: Simplified VFD Wiring
Before beginning any service, disconnect all power to
the drive. Be aware that high voltages are present in the
drive even after power has been disconnected.
Capacitors within the drive must be allowed to discharge
before beginning service.
Do not connect AC power to the T1, T2, T3 drive
terminals to prevent damage to the VFD.
The fuses (FU3, FU4, FU5) supplied with the unit are
sized according to the electrical load of the blower
motor, but may not provide adequate protection to the
customer-installed drive, depending upon its
specifications. Once a drive has been selected and
installed, refer to the drive manufacturer's
recommendations for proper fuse sizing.
ELEMENTARY DIAGRAM
VFD
TB8 (IN CONTROL BOX)
RUN PERMIT
(DIGITAL)
SPEED REF
(ANALOG)
(2-10 VDC)
GND
GRN
GND
GRN
GND
1 DMTR
118 / BK
119 / BR
120 / Y
3
M
(T1)
(T2)
(T3)
( )
(L1)
(L3)
(L2)
722 / BK
725 / BR
728 / Y
720 / PR
723 / BR
726 / O
TB1
FU3
FU5
FU4
1
2
3
4
5
6
L3
L2
L1
T1
T2
T3
