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Installation Instructions

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.

PACKAGE CONTENTS

ITEM

QUANTITY*

Thermistor

2

Transducer

4

Compression Fitting

2

Wire Nuts (2 types)

13

PSIO1 Plug Assembly

1

Transducer Plug Harness

4

Connection Box

2

Connection Box Cover

2

Connection Box Connector

4

Connection Box Bracket

1

PVC-Jacketed Cable

28 ft

Red and Black Wire Assembly

2

Varnish Cloth

4

Wire Tie

2

Screw

2

*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.

TRANSDUCER

1/4-IN. FEMALE QUICK CONNECTS

RED AND BLACK
WIRES (USED
FOR 034-074
UNITS ONLY)

PSIO PLUG
ASSEMBLY

PVC-JACKETED CABLE

TRANSDUCER PLUG HARNESS

LEAD END

THERMISTOR

PROBE END

COMPRESSION
FITTING

WIRE NUTS

NOTE: Screws, varnish cloth, connectors, connection boxes and
covers, and connection box mounting bracket not shown.

Fig. 1 — Package Contents

48NP/50NB,NP

Accessory Pressure Transducer

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Book 1

1

Tab

1a 1b

PC 111

Catalog No. 564-923

Printed in U.S.A.

Form 48/50N-1SI

Pg 1

12-93

Replaces: New

Summary of Contents for 48NP

Page 1: ...oring PACKAGE CONTENTS ITEM QUANTITY Thermistor 2 Transducer 4 Compression Fitting 2 Wire Nuts 2 types 13 PSIO1 Plug Assembly 1 Transducer Plug Harness 4 Connection Box 2 Connection Box Cover 2 Connec...

Page 2: ...reference there will already be a violet wire attached to TB2 terminal 4 and an orange wire attached to TB2 terminal 3 ALL UNITS Locate the PSIO1 plug assembly in the accessory kit see Fig 1 This wil...

Page 3: ...LEGEND PL Plug Assembly PSIO Processor Module TB Terminal Block NOTE The PSIO1 module is located underneath the PSIO2 module Fig 3 Control Box 034 044 3...

Page 4: ...or Evaporator Fan Contactor MMC Head Pressure Control Device OAT Outdoor Air Thermostat OFC Outdoor Condenser Fan Contactor PSIO Processor Module RAT Return Air Thermistor SAT Supply Air Thermistor SC...

Page 5: ...ermistors probe ends un derneath the baffle in the condenser section over to the compressors with the marked thermistor going to com pressor no 1 See Fig 6 and 7 034 044 UNITS Connect the thermistors...

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 6...

Page 7: ...section with the marked cable and ther mistor going to compressor no 1 Compressor Section Wiring This section will de tail the accessory kit wiring in the compressor section When instructed to plug ea...

Page 8: ...ng varnish cloth 6 Locate the 4 transducer plug harness assemblies in the accessory package 7 Plug one of these into the discharge and suction trans ducers for each compressor Mark the white wire in t...

Page 9: ...uction Pressure HEAT Heat Type Sensor HPSP Head Pressure SUSN Suction Sensors Set Point TRNS Transducers HUSN Humidity Sensors ULOP Number of Unloaders After approximately 20 seconds the HSIO keypad a...

Page 10: ...itting threaded into the discharge valve body 3 Unplug the harness from the proper transducer 4 Thread the transducer onto the flare fitting and tighten See Fig 13 16 5 Reconnect the transducer harnes...

Page 11: ...and Discharge Valve Stem Cap Locations 044 Units Compressors 1 and 2 054 Units Compressor 2 DANGER DISCHARGE VALVE STEM CAP LOW PRESSURE SWITCH Fig 12 Low Pressure Switch and Discharge Valve Stem Cap...

Page 12: ...SSURE SWITCH WIRE TIE SUCTION GAS THERMISTOR INSTALLED SUCTION LINE Fig 13 Transducers and Thermistor Installed 024 030 Units SUCTION PRESSURE TRANSDUCER DISCHARGE PRESSURE TRANSDUCER COMPRESSION FITT...

Page 13: ...15 Transducers and Thermistor Installed 044 Units Compressors 1 and 2 054 Units Compressor 2 DANGER DISCHARGE PRESSURE TRANSDUCER COMPRESSION FITTING SUCTION GAS THERMISTOR SUCTION PRESSURE TRANSDUCER...

Page 14: ...and tighten 3 4 to 1 full turn with a wrench to ensure a tight seal DO NOT OVERTIGHTEN 7 Turn the valve stem 1 to 11 2 full turns clockwise Check compression fitting seal for leaks and tighten nut if...

Page 15: ...supplied to transducer 5 Transducer failure 0 0 psig Transducer is not sensing any pressure 1 Service valve is not opened 2 Valve core is not being depressed 205 psig Open circuit at PSIO1 PSIO1 J7 p...

Page 16: ...cturer reserves the right to discontinue or change at any time specifications or designs without notice and without incurring obligations Book 1 1 Tab 1a 1b PC 111 Catalog No 564 923 Printed in U S A...

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