Specifications

No Motormastert Control — The fans are controlled based
on Saturated Condensing Temperature. The first fan stage
for each circuit is turned on whenever the compressor is turned
on. A fan stage is added when the Saturated Condensing Tem-
perature (SCT) exceeds the Head Pressure Set Point. The
Head Pressure Set Point is configurable in the Set Point sub-
function. The default is 113 F (45 C). Once a fan stage has
been added, the software temporarily modifies the head pres-
sure set point by adding 15° F (8.3° C) for 35 seconds. A
fan stage will be removed when the Saturated Condensing
Temperature has been less than the Head Pressure Set Point
minus 35 F (19.4 C) for 2 minutes. The control uses the higher
of the 2 Saturated Condensing Temperature values for
30GX080-150 and 160 units. For the 30GX151 and 161-265
units, each circuit’s fan stages are independently controlled
based on the circuit Saturated Condensing Temperature.
Refer to Table 6 for condenser fan control information. See
Fig. 6A.
With Motormaster Control — For low-ambient operation,
the lead fan in each circuit can be equipped with the optional
or accessory Motormaster III head pressure controller. This
controller can be used in one of 2 ways. If factory installed,
the controller will be configured for 4 to 20 mA control. With
the Motormaster III option enabled, the PSIO-1 module cal-
culates the required output based on Saturated Condensing
temperature, Head Pressure set point, and a PID (propor-
tional integral derivative) loop calculation. This 4 to
20 mA output is driven through the PSIO-2 module. To ob-
tain this accessory for field installation, order by part num-
ber 30GX-900---012 for a single controller package (30GX080-
150 and 160). Order part number 30GX-900---014 for a
dual controller package (30GX151 and 161-265). These
packages contain all the hardware required to install the
accessory. See Fig. 6B.
The control will use the higher of the 2 Saturated Con-
densing Temperature values for 30GX080-150 and 160 units.
For the 30GX151 and 161-265 units, each circuit’s fan stages
are independently controlled based on the circuit Saturated
Condensing Temperature. Refer to Table 6 for condenser fan
staging information.
WATER-COOLED UNITS (30HX) — The 30HX chillers
can be configured to control direct or reverse-acting water
valves that are controlled bya4to20mAsignal. A 2 to
10 VDC signal can be used by installing a 500-ohm resistor
across the 2 output terminals of the 4 to 20 mA signal. This
control scheme reads the saturated condensing temperature
and uses a PID (proportional integral deriative) loop to
control the head pressure. Proportional, Integral and Deriva-
tive gain parameters for both the water and air cooled con-
trols are adjustable and can be found in the Service subfunc-
tion. Checkout and adjustment of the PID loop should
only be performed by certified Carrier Comfort Network
technicians.
Table 4 — Field Configured Chiller Options
CONFIGURATION OPTION DESCRIPTION HSIO LOCATION FACTORY CONFIGURED?
Fan Staging Select Air cooled staging method
Yes. See Table 5
Motormaster Control Select Applies to air cooled units only
Yes. 0 = None
Set to 1 to enable (Motormaster only)
Water Valve Type Applies to water cooled unit only
Yes. 0 = None
Setto1=4−20mA,2=0−10V,
3=20−4mA,4=10−0V
Table 5 — Fan Staging Settings for Air Cooled (30GX) Units
UNIT 30GX DESCRIPTION OPTION NUMBER
080-105
1st stage compressor status
2nd stage common control based on highest SCT
12
106-125
1st stage compressor status
2nd and 3rd stage common control based on highest SCT
14
136, 150, 160
1st stage compressor status
2nd through 4th stage common control based on highest SCT
16
151, 161, 175,
205, 225
1st stage each circuit, compressor status
2nd stage Circuit B independent
2nd and 3rd stage Circuit A independent
7
176
1st stage each circuit, compressor status
2nd and 3rd stage each circuit independent
3
206, 226, 250
1st stage each circuit, compressor status
2nd stage Circuit B independent
2nd, 3rd and 4th stage Circuit A independent
9
251, 265
1st stage each circuit, compressor status
2nd, 3rd and 4th stage each circuit independent
5
LEGEND
SCT — Saturated Condensing Temperature
9