Carrier AquaForce 30XV140 Controls, Start-Up, Operation, Service And Troubleshooting Instructions page 49

THERMISTORS (Tables 32-34) — Thermistors that monitor
the chiller's operation include: evaporator entering water,
evaporator leaving water, dual chiller leaving water, com-
pressor suction gas temperature, compressor discharge gas
temperature, economizer temperature, liquid line tempera-
ture, compressor motor temperature, and outdoor air tem-
perature thermistors. These thermistors are 5,000 ohms at
77 F (25 C) and are identical in temperature versus resis-
tance. The space temperature thermistor is 10,000 ohmsat
77 F (25 C) and has a different temperature vs. resistance.
See Fig. 43 for thermistor locations.
Evaporator Leaving Water Sensor — On all sizes, this therm-
istor is installed in a friction fit well in the leaving water nozzle
of the evaporator. See Fig. 44.
Evaporator Entering Water Sensor — On all sizes, this
thermistor is factory-installed in a friction fit well in the enter-
ing water nozzle of the evaporator.
Suction Gas Temperature — On all sizes, this thermistor is
factory-installed in a friction fit well located on the compressor
of each circuit. There is one thermistor for each circuit.
Compressor Discharge Gas Temperature — On all sizes, this
thermistor is factory-installed in a friction fit well located in the
discharge end of the compressor for the circuit. There is one
thermistor for each circuit.
Liquid Line Temperature — This thermistor is factory-in-
stalled in a friction fit well located in the liquid line of the cir-
cuit. There is one thermistor for each circuit.
Economizer Temperature — On all sizes, this thermistor is
factory-installed in a friction fit well located in the economizer
line for the circuit. There is one thermistor for each circuit.
Compressor Motor Temperature — On all sizes, this therm-
istor is embedded in the motor windings. There are two therm-
istors in each compressor. One spare is provided.
Outdoor Air Temperature — This sensor is factory-installed
to the back of the control box.
Remote Space Temperature — This sensor (part no.
33ZCT55SPT) is a field-installed accessory mounted in
the indoor space and is used for water temperature reset.
The sensor should be installed as a wall-mounted thermo-
stat would be (in the conditioned space where it will not
THERMISTOR ID
EWT Entering Water Thermistor
LWT Leaving Water Thermistor
OAT Outdoor Air Thermistor
SGTA Circuit A Suction Gas Thermistor
SGTB Circuit B Suction Gas Thermistor
DGTA Circuit A Discharge Gas Thermistor
DGTB Circuit B Discharge Gas Thermistor
LIQT_A Circuit A Liquid Line Thermistor
LIQT_B Circuit B Liquid Line Thermistor
ECTA Circuit A Economizer Thermistor
ECTB Circuit B Economizer Thermistor
DUAL Dual Chiller LWT Thermistor
CAMT Circuit A Motor Temperature
CBMT Circuit B Motor Temperature
SPT Space Temperature Thermistor
Table 32 — Thermistor Identification
DESCRIPTION
49
be subjected to either a cooling or heating source or di-
rect exposure to sunlight, and 4 to 5 ft above the floor).
Space temperature sensor wires are to be connected to ter-
minals in the unit main control box. See Fig. 45. The space
temperature sensor includes a terminal block (SEN) and a RJ11
female connector. The RJ11 connector is used as access into
the Carrier Comfort Network
To connect the space temperature sensor (see Fig. 45):
1. Using a 20 AWG (American Wire Gage) twisted pair
conductor cable rated for the application, connect one
wire of the twisted pair to one SEN terminal and connect
the other wire to the other SEN terminal located under the
cover of the space temperature sensor.
2. Connect the other ends of the wires to terminals 7 and 8
on TB6 located in the unit control box.
Units on the CCN can be monitored from the space at the
sensor through the RJ11 connector, if desired. To wire the RJ11
connector into the CCN:
1. Cut the CCN wire and strip ends of the red (+), white
(ground), and black (–) conductors. (If another wire color
scheme is used, strip ends of appropriate wires.)
2. Insert and secure the red (+) wire to terminal 5 of the
space temperature sensor terminal block.
3. Insert and secure the white (ground) wire to terminal 4 of
the space temperature sensor.
4. Insert and secure the black (–) wire to terminal 2 of the
space temperature sensor.
5. Connect the other end of the communication bus cable to
the remainder of the CCN communication bus.
NOTE: The energy management module (EMM) is required
for this accessory.
TRANSDUCERS — There are 5 pressure transducers per cir-
cuit, and two different types of transducers: low pressure
(green connector) and high pressure (black connector).
Low Pressure Type: suction pressure transducer (SPT), econo-
mizer pressure transducer (EPT).
High Pressure Type: discharge pressure transducer (DPT), oil
pressure transducer (OPT), liquid line pressure transducer
(LPT). See Fig. 46 for transducer locations.
RESISTANCE AT 77 F (25 C)
5k 
5k 
5k 
5k 
5k 
5k 
5k 
5k 
5k 
5k 
5k 
5k 
5k 
5k 
10k 
(CCN) at the sensor.
®
CONNECTION POINT
SIOBA-J25-AI01
SIOBA-J25-AI02
SIOBA-J25-AI03
AUXA-J6-CH12
AUXB-J6-CH12
AUXA-J6-CH11
AUXB-J6-CH11
AUXA-J7-CH13
AUXB-J7-CH13
SIOBA-J25-AI05
SIOBB-J25-AI05
SIOBB-J25-AI03
SIOBA-J25-AI04
SIOBB-J25-AI04
EMM-J6-CH2