Sensors; Cooler Leaving Fluid Sensor; Cooler Entering Fluid Sensor; Condenser Leaving Fluid Sensor - Carrier AQUASNAP MPW015-045 Operation And Service Manual

IMPORTANT: A shorted CCN bus cable will prevent some
routines from running and may prevent the unit from start-
ing. If abnormal conditions occur, unplug the connector. If
conditions return to normal, check the CCN connector and
cable. Run new cable if necessary. A short in one section of
the bus can cause problems with all system elements on the
bus.
Table 15 — Thermistor Designations
PIN
THERMISTOR CONNECTION
POINT
CLWT J8-13,14 (MBB) Cooler Leaving Fluid
CEWT J8-11,12 (MBB) Cooler Entering Fluid
J8-9,10 (MBB)
RGTA
J8-6,7 (MBB),
OAT LVT 4,13
J8-5,6 (MBB)
SPT
LVT-3,4
J8-1,2
CNDE
J8-3,4
CNDL
LEGEND
LWT — Leaving Water Temperature
MBB — Main Base Board
Table 16 — Status Inputs
STATUS SWITCH
Condenser Flow Switch
Dual Set Point
Remote On/Off
Cooler Flow Switch Interlock
Compressor Fault Signal, A1
Compressor Fault Signal, A2
Compressor Fault Signal, A3
Table 17 — Output Relays
RELAY
NO.
K1 Energize Compressor A1
K2 Energize Compressor A2
K3 Energize Compressor A3
K4 Energize Minimum Load Valve
K5 Water Valve Open
K6 Water Valve Close
K7 Liquid Line Solenoid Valve
K8 Crankcase Heater Relay (30MPA Only)
K9 Chilled Water Pump
K10 Condenser Fan/Pump
K11 Alarm Relay
Table 18 — CCN Communication Bus Wiring
MANUFACTURER
Regular Wiring
Alpha
American A21451
Belden
Columbia D6451
Manhattan M13402
Quabik
The electronic control uses 2 to 7 thermistors to
Sensors —
sense temperatures for controlling chiller operation. See
Table 15. These sensors are outlined below. Thermistors
THERMISTOR INPUT
Circuit A Return Gas
Temperature (accessory)
Outdoor-Air Temperature
Sensor (accessory) or Dual
LWT Sensor
Accessory Remote Space

Temperature Sensor

Condenser Entering Water
Temperature Sensor
Condenser Leaving Water
Temperature Sensor
PIN CONNECTION POINT
LVT-11,17, J7-2, J6-2
LVT-12,13, J7-3,4
LVT-14,15
LVT-16,17, J6-2, J7-10
J9-11,12
J9-5,6
J9-8,9
DESCRIPTION
PART NO.
Plenum Wiring
1895 —
A48301
8205 884421
—
M64430
6130 —
RGTA, CNDE, CNDL, EWT, LWT, and OAT are identical in
temperature versus resistance and voltage drop performance.
The dual chiller thermistor (DLWT) is 5 k at 77 F (25 C)
thermistor. Space temperature thermistor (SPT) is a 10 kat
77 F (25 C). See Thermistors section for temperature-resis-
tance-voltage drop characteristics.
COOLER LEAVING FLUID SENSOR (LWT) — The thermis-
tor is installed in a well in the factory-installed leaving fluid
piping coming from the bottom of the brazed-plate heat
exchanger.
COOLER ENTERING FLUID SENSOR (EWT) — The therm-
istor is installed in a well in the factory-installed entering fluid
piping coming from the top of the brazed-plate heat exchanger.
CONDENSER LEAVING FLUID SENSOR (CNDL) —
thermistor is installed in a well in the factory-installed leaving
fluid piping coming from the bottom of the brazed-plate heat
exchanger.
COOLER ENTERING FLUID SENSOR (CNDE) — The therm-
istor is installed in a well in the factory-installed entering fluid
piping coming from the top of the brazed-plate heat exchanger.
COMPRESSOR RETURN GAS TEMPERATURE SEN-
SOR (RGTA) — This accessory thermistor can be installed in
a well located in the suction line.
OUTDOOR-AIR TEMPERATURE SENSOR (OAT) —
This sensor is an accessory that is remotely mounted and used
for outdoor air temperature reset. See Table 15.

DUAL LEAVING WATER TEMPERATURE SENSOR

(DLWT) — This input can be connected to the LVT. See Ta-
ble 15. For dual chiller applications (parallel only are support-
ed), connect the dual chiller leaving fluid temperature sensor
(5 kthermistor, Carrier part no. HH79NZ029) to the outside
air temperature input of the Master chiller. If outside air tem-
perature is required for reset applications, connect the sensor to
the Slave chiller and configure the slave chiller to broadcast the
value to the Master chiller.
REMOTE SPACE TEMPERATURE SENSOR (SPT) —
The sensor (part no. 33ZCT55SPT) is an accessory sensor that
is remotely mounted in the controlled space and used for space
temperature reset. The sensor should be installed as a wall-
mounted thermostat would be (in the conditioned space where
it will not be subjected to either a cooling or heating source or
direct exposure to sunlight, and 4 to 5 ft above the floor).
Space temperature sensor wires are to be connected to
terminals in the unit main control box. The space temperature
sensor includes a terminal block (SEN) and a RJ11 female
connector. The RJ11 connector is used access into the Carrier
Comfort Network ® (CCN) at the sensor.
To connect the space temperature sensor (Fig. 8):
1. Using a 20 AWG twisted pair conductor cable rated for
the application, connect 1 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 3 and 4
on LVT 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 (Fig. 9):
IMPORTANT: The cable selected for the RJ11 connector
wiring MUST be identical to the CCN communication bus
wire used for the entire network. Refer to Table 18 for
acceptable wiring.
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.)
19
The