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GENERAL
The accessory refrigerant pressure transducer and suc-
tion superheat package is intended for use with the
48NP/50NB,NP units only. When installed using these in-
stallation instructions, this accessory package will improve
head pressure control, as well as provide increased diagnos-
tic capability by monitoring compressor discharge and suc-
tion pressures and suction superheat. See Package Contents
table and Fig. 1 for package contents.
Installation of the discharge pressure transducers in this
kit will replace the function of the saturated condensing tem-
perature thermistors (T3 and T4), and installation of the suc-
tion pressure transducers will replace the function of the low-
pressure switches. The control will no longer require inputs
from these thermistors and switches once this installation is
complete.
IMPORTANT: The PSIO2 accessory package number
50DJ902431 must also be installed in order to provide
suction superheat monitoring.
THERMISTOR
PROBE END
COMPRESSION
FITTING
NOTE: Screws, varnish cloth, connectors, connection boxes and
covers, and connection box mounting bracket not shown.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 1
PC 111
Tab
1a 1b
Accessory Pressure Transducer
Installation Instructions
TRANSDUCER PLUG HARNESS
LEAD END
WIRE NUTS
Fig. 1 — Package Contents
Catalog No. 564-923
Printed in U.S.A.
48NP/50NB,NP
PACKAGE CONTENTS
ITEM
Thermistor
Transducer
Compression Fitting
Wire Nuts (2 types)
PSIO1 Plug Assembly
Transducer Plug Harness
Connection Box
Connection Box Cover
Connection Box Connector
Connection Box Bracket
PVC-Jacketed Cable
Red and Black Wire Assembly
Varnish Cloth
Wire Tie
Screw
*Not all items will be used in each installation. Refer to the Installation
section for the items and quantities required for each individual in-
stallation. Extra parts not needed may be discarded.
PVC-JACKETED CABLE
PSIO PLUG
ASSEMBLY
TRANSDUCER
1/4-IN. FEMALE QUICK CONNECTS
Form 48/50N-1SI
QUANTITY*
2
4
2
13
1
4
2
2
4
1
28 ft
2
4
2
2
RED AND BLACK
WIRES (USED
FOR 034-074
UNITS ONLY)
Pg 1
12-93
Replaces: New
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Summary of Contents for Carrier 48NP
- Page 1 The accessory refrigerant pressure transducer and suc- ITEM QUANTITY* tion superheat package is intended for use with the Thermistor 48NP/50NB,NP units only. When installed using these in- Transducer stallation instructions, this accessory package will improve Compression Fitting head pressure control, as well as provide increased diagnos-...
-
Page 2: Installation
connect terminal on one end. Connect the red wire to TB2 INSTALLATION (terminal block), terminal 4. Connect the black wire to TB2, Control Box — Make the control box wiring connec- terminal 3. See Fig. 4. tions as follows: NOTE: For your reference, there will already be a violet wire 024-030 UNITS —... - Page 4 LEGEND — Contactor — Outdoor-Air Thermostat — Circuit Breaker — Outdoor (Condenser) Fan Contactor — Control Circuit Breaker PSIO — Processor Module CONT — Control — Return Air Thermistor — Discharge Pressure Transducer — Supply Air Thermistor — Dummy Terminal —...
- Page 5 11. Run the other ends of the 2 thermistors (probe ends) un- Thermistor and PSIO Module Wiring derneath the baffle in the condenser section over to the 024-030 UNITS — Connect the thermistors and transducer compressors with the marked thermistor going to com- harness wires as follows: pressor no.
- Page 6 Thermistor (Probe End) Routing Fig. 6 — Control Box Location and Thermistor Routing, 024-030 Thermistor (Probe End) Routing Fig. 7 — Thermistor Probe End Routing, 024-030 Units...
- Page 7 9. Connect all four black wires from the transducer har- Compressor Section Wiring — This section will de- nesses (with a wire nut provided) to the other end of the tail the accessory kit wiring in the compressor section. When black wire that was connected to TB3 earlier.
- Page 8 5. Connect the transducer plug harness (the one where the 6. Locate the 4 transducer plug harness assemblies in the white wire on the other end is connected to PSIO1, J7- accessory package. TOP, pin 10) to the discharge pressure transducer for com- 7.
- Page 9 Controls Configuration and Calibration — KEYPAD ACTION BEING HSIO ENTRY fore installing the transducers into the compressors, the con- DISPLAY TAKEN trols must be reconfigured and the transducers calibrated. LOG ON Enter login function Proceed as follows: 1. Reconnect power to the rooftop unit. LOGGEDON Logging in 2.
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Page 10: Transducer Installation
Suction temperature readings of −40.0 or 245.0 indicate 2. Remove the flare cap from the fitting threaded into the an open or shorted circuit (respectively). Verify that the wir- discharge valve body. ing connections to PSIO2 have been made correctly. If the 3. - Page 11 DISCHARGE VALVE STEM CAP LOW-PRESSURE SWITCH Fig. 11 — Low-Pressure Switch and Discharge Valve Stem Cap Locations (044 Units, Compressors 1 and 2; 054 Units, Compressor 2) DISCHARGE VALVE LOW-PRESSURE STEM CAP SWITCH Fig. 12 — Low-Pressure Switch and Discharge Valve Stem Cap Locations (054 Units, Compressor 1;...
- Page 12 SUCTION GAS WIRE TIE SUCTION PRESSURE TRANSDUCER SUCTION LINE THERMISTOR INSTALLED (FORMER LOCATION OF LOW-PRESSURE SWITCH) DISCHARGE PRESSURE TRANSDUCER Fig. 13 — Transducers and Thermistor Installed (024-030 Units) DISCHARGE PRESSURE SUCTION PRESSURE TRANSDUCER TRANSDUCER COMPRESSION FITTING SUCTION GAS THERMISTOR Fig. 14 — Transducers and Thermistor Installed (034 Units)
- Page 13 DISCHARGE PRESSURE TRANSDUCER SUCTION PRESSURE TRANSDUCER COMPRESSION FITTING SUCTION GAS THERMISTOR Fig. 15 — Transducers and Thermistor Installed (044 Units, Compressors 1 and 2; 054 Units, Compressor 2) DISCHARGE PRESSURE TRANSDUCER SUCTION PRESSURE TRANSDUCER COMPRESSION FITTING SUCTION GAS THERMISTOR Fig. 16 — Transducers and Thermistor Installed (054 Units, Compressor 1; 064,074 Units, Compressors 1 and 2)
- Page 14 SUCTION GAS THERMISTOR — The thermistors that were Compressor System Pressure Check — Use the wired into the control box must now be installed on each accessory HSIO keypad and display module (see Fig. 9) to compressor. perform the following: 024-030 Units —...
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Page 15: Pressure Reading
PRESSURE TROUBLESHOOTING PRESSURE READING POSSIBLE CAUSES POSSIBLE SOLUTIONS 1. Transducer plug is not plugged in. 2. Pull-down resistor shorted.* No output signal received from transducer by −6.7 psig 3. Wiring error the PSIO1 Module 4. Power not supplied to transducer 5. - Page 16 Copyright 1993 Carrier Corporation Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations. Book 1 1 PC 111 Catalog No. 564-923 Printed in U.S.A. Form 48/50N-1SI Pg 16 12-93...
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