FORM 150.66-NM2
ISSUE DATE: 09/25/2020
137
JOHNSON CONTROLS
SECTION 8 - UNIT OPERATION
8
CONFIGURATION (JUMPERS AND
POTENTIOMETERS)
Each VFD is pre-configured at the factory prior to
shipping and should be ready for operation when
it arrives onsite. A quick check of the settings is
recommended. The jumpers must be in the positions
shown in the following table.
Chillers built in 2005 and early 2006 were
configured with J4 IN. This jumper must
be removed. Also be sure to check J2 and
remove if necessary.
VFD JUMPERS
J2
REMOVE
—
J3
IN
—
J4
REMOVE
—
J5
IN
—
J6
IN
—
J7
IN
—
J8
IN
—
J9
IN FOR 60 hZ
REMOVE FOR 50 hZ
Potentiometer settings are also preset at the factory. The
potentiometers should be in the positions shown in Fig.
24. The pots do not have numerical settings and are set
according to the arrow positions indicated. DO NOT
change the potentiometer settings unless they do not
match the positioning of the potentiometers shown in
Fig. 24. P1 should be full CW (180 psig) and P2 should
be full CCW (20 psig). Modifying these settings may
cause damage to the chiller or control problems.
The P1 pot sets the setpoint which is the top end of the
control range. This setting is the discharge pressure at
which the fan will be operating at full speed. The P2
pot sets the range. This is the range of pressure where
the VSD modulates the fan speed from 0 RPM to full
speed. The range is subtracted from the setpoint to
calculate the 0 RPM pressure.
Wiring
VFD wiring is simple and requires only 3-phase power
in, 3-phase power out, and a 2-wire signal from the
transducer. No start, stop, or other alternate power
requirements are needed to run the VFD. Fig’s 23 and
25 show the power and control wiring schematically as
well as the actual connections. The VFD controlled fan
will operate whenever the liquid line solenoid on the
respective system is energized
On chillers with low ambient option,
wire 127 is removed from TB79 and
connected to TB73.
FIG. 23 – INVERTER POWER WIRING SCHEMATIC
lD11301a
150A
L1
T1
150
151A
L2
T2
151
152A
L3
T3
152
CONDENSER
FAN NO. 1
SPEED
CONTR.
7M
POTENTIOMETER SETTINGS
P1
P2
180 PSI
20 PSI
FIG. 24 – POTENTIOMETER SETTINGS
P1
P2
P1
P2
lD11300A
Summary of Contents for YCAL0012EC
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