Safety Devices; Compressor Protection; Cooler Protection; Relief Devices - Carrier Ecologic 30GX080-265 Controls, Start-Up, Operation, Service, And Troubleshooting

Table 40 — Thermistor Temperatures vs
Resistance, Motor Temperature Thermistors
TEMP TEMP
(F) (C)
−22 −30
−13 −25
−4 −20
5 −15
14 −10
23 −5
32 0
41 5
50 10
59 15
68 20
77 25
86 30
95 35
104 40
113 45
122 50
131 55
140 60
149 65
158 70
167 75
176 80
185 85
194 90
203 95
212 100
221 105
230 110
239 115
248 120
NOTE: Motor temperature thermistor values must be verified using
resistance. Voltage drop cannot be used.
Table 41 — Thermistor Depth
UNIT MODEL
NUMBER
30GX080-090
30GX105-115
30GX125-136
30GX150,151
30GX160,161
30GX175,176
30GX205-226
30GX250-265
30HXA,C076-086
30HXA,C096
30HXA,C106
30HXA,C116-126
30HXA,C136-146
30HXA,C161-171
30HXA,C186
30HXA,C206
30HXA,C246-271
Table 42 — Calibrating Pressure Transducers
(Pressure Gage Installed)
KEYPAD ENTRY DISPLAY RESPONSE
CALIBRATION
OFFSET
CIRCUIT A
PRESSURE
Discharge Pressure
84.2 PSI
Discharge Pressure
85.0 PSI
RESISTANCE
(Ohms)
88,480.0
65,205.0
48,536.0
36,476.0
27,663.0
21,163.0
16,325.0
12,696.0
9,949.5
7,855.5
6,246.0
5,000.0
4,028.4
3,265.7
2,663.2
2,184.2
1,801.2
1,493.1
1,243.9
1,041.4
875.8
739.7
627.6
534.9
457.7
393.3
339.3
293.8
255.3
222.6
194.8
THERMISTOR DEPTH
''X''-in. (mm)
6.00 (152.4)
4.25 (108.0)
5.56 (141.2)
6.00 (152.4)
4.25 (108.0)
4.25 (108.0)
3.94 (100.0)
4.82 (122.4)
5.13 (130.3)
6.00 (152.4)
4.25 (108.0)
5.13 (130.3)
6.00 (152.4)
4.25 (108.0)
5.56 (141.2)
3.94 (100.0)
4.82 (122.4)
COMMENTS
Current reading is
displayed.
Enter gage pressure
reading to nearest
tenth. Control will
allow offset of up to
6 psig. Transducer
calibration is now
complete.
Safety Devices —
safety devices and protection logic built into the electronic
control. Following is a description of the major safeties.

COMPRESSOR PROTECTION

Motor Overload — One factory preset solid-state overload
protects each compressor against overcurrent. Do not by-
pass the overload or make any changes to the overload
setting. Determine the cause for trouble and correct the prob-
lem before resetting a tripped overload. In addition to the
overload, each compressor is further protected by the
Compressor Protection Module. Each module has a factory
installed and configured 8-pin header. The configuration of
this header defines the must-trip amps at which the CPM
will turn the compressor off. See Appendix D for correct set-
ting of overload and configuration headers.
Each CPM board also reads the status of each compres-
sor's high-pressure switch. All compressors have factory-
installed high-pressure switches. For 30GX units, the switch
is set to trip at 303 ± 7 psig (2089 ± 48 kPa). The setting
for 30HXA units is 275 ± 7 psig (1896 ± 48 kPa) and for
30HXC units the setting is 191 ± 7 psig (1317 ± 48 kPa).
If the switch opens during operation, the compressor will be
shut down. The CPM will reset automatically when the
switch closes, however, a manual reset is required to restart
the compressor.
OIL SEPARATOR HEATERS (30GX) — Each oil separator
circuit has a heater mounted on the underside of the vessel.
The heater is energized with control circuit power. After a
prolonged shutdown or service job, additional time may be
required before starting the unit. Oil heaters are energized
when the discharge gas temperature falls below 105 F
(40.6 C). The heaters are deenergized when the discharge
gas temperature rises above 110 F (43.3 C). The control will
allow the chiller to attempt to start with the heaters ener-
gized and will keep the heaters on, even when running, until
the discharge gas temperature reaches 110 F (43.3 C). Note
that the oil heaters are deenergized if the oil level switch is
open.

COOLER PROTECTION

Low Water Temperature — Microprocessor is programmed
to shut the chiller down if the leaving fluid temperature drops
below 34 F (1.1 C) for water or more than 8° F (4.4° C)
below set point for brine units. When the fluid temperature
rises 6° F (3.3° C) above the leaving fluid set point, the safety
resets and the chiller restarts. Reset is automatic as long as
this is the first occurrence of the day.
IMPORTANT: If the unit is installed in an area where
ambient temperatures fall below 32 F (0° C), inhibited
ethylene glycol or other suitable solution must be used
in the chilled fluid circuit.
Relief Devices —
cuit (30GX only) between the condenser and the liquid line
shutoff valve.
PRESSURE RELIEF VALVES — Valves are installed in each
circuit and are located on all coolers. One relief valve is also
installed on each 30HXC condenser. Both circuits' oil sepa-
rators on 30GX and 30HXA units have factory-installed
relief valves as well. These valves are designed to relieve if
an abnormal pressure condition arises. Relief valves on all
coolers and 30HXC condensers relieve at 220 psi (1517 kPa).
Relief valves on 30GX and 30HXA oil separators relieve at
320 psi (2206 kPa). Units with factory-installed suction serv-
ice valves also have a relief valve in each compressor dis-
charge line. These valves are designed to relieve at 350 psig
(2413 kPa). These valves should not be capped. If a valve
relieves, it should be replaced. If the valve is not replaced,
it may relieve at a lower pressure, or leak due to trapped dirt
from the system which may prevent resealing.
62
The 30GX/HX chillers contain many
Fusible plugs are located in each cir-