Suction Pressure Transducer (Spt) - Carrier Infinity 25VNA0 Service Manual

25VNA0 Outdoor Coil Thermistor
The outdoor coil thermistor is a 10Kohm resistor used for multiple
system operations. It provides the coil/liquid line temperature to
the HP board and user interface. Low ambient operation, defrost
initiation, defrost termination and assistance with OAT temperature
measurement of some of the functions.
securely mounted to the tube connecting the EXV and distributor.
See Fig.8 for proper placement.
Fig. 7 – 24VNA0 Outdoor Coil Thermistor (OCT) Attachment
(On Distributor Tube)
Fig. 8 – 25VNA0 Outdoor Coil Thermistor (OCT) Attachment
(On Distributor Tube)
OAT Thermistor must be
locked in place with
spherical nib end facing
towards the front of the
control box
Fig. 9 – OAT Thermistor Location (Bottom of Control Box)
24VNA0 Suction Thermistor (OST)
Suction Thermistor is used for compressor protection and must be
secured on the suction tube and aligned longitudinally to the
vertical surface of the tube axis (see Fig. 10).
The sensor must be
25VNA0 Suction Thermistor (OST)
Suction Thermistor is used for assisting in EXV control and must
A14328
be secured on the suction tube and aligned longitudinally to the
vertical surface of the tube axis (see Fig. 11).
OCT SENSOR
LOCATION
A11143

Suction Pressure Transducer (SPT)

These units use a 5 VDC output low pressure transducer that
provides a 0- -5VDC data for interpretation by the control board a 0
to 200 psig range of pressure at the suction tube.
Signals used by control board for:
If the accuracy of the transducer is questioned, the technician can
check it while it is attached to the VS board. Connect a gage
A11142
manifold to the suction valve gage port fitting.
At the VS board, with the wire harness receptacle exposing a
portion of the three pins on the VSHP board, a DC voltmeter can
10
Fig. 10 – 24VNA0 Suction Thermistor (OST) Attachment
(On Suction Tube)
PRESSURE TRANSDUCER (SPT)
SUCTION TUBE
SUCTION THERMISTOR (OST)
ACCUMULATOR
REVERSING VALVE
SUCTION SERVICE VALVE
Fig. 11 – 25VNA0 Suction Thermistor (OST) Attachment
(On Suction Tube)
S Low pressure cut- -out
S Loss of charge management,
S Compressor overall envelope management
S Oil circulation management
S Lubrication management and
S EXV control.
A170294
ACCUMULATOR TUBE
COMPRESSOR
A11103