York YLAA0195HE, Manual, Page: 8 / 206

JOHNSON CONTROLS
8
FORM 150.72-NM3 (1020)
ISSUE DATE 10/05/2020
SECTION 8 – UNIT OPERATION .................................................................................................................167
CAPACITY CONTROL ............................................................................................................................167
SUCTION PRESSURE LIMIT CONTROLS ...........................................................................................167
DISCHARGE PRESSURE LIMIT CONTROLS .....................................................................................167
LEAVING CHILLED LIQUID CONTROL ...............................................................................................167
LEAVING CHILLED LIQUID SYSTEM LEAD/LAG AND COMPRESSOR SEQUENCING ..............168
LEAVING CHILLED LIQUID CONTROLOVERRIDE TO REDUCE CYCLING ..................................168
RETURN CHILLED LIQUID CONTROL ................................................................................................169
RETURN CHILLLED LIQUID SYSTEM LEAD/LAG AND COMPRESSOR SEQUENCING .............170
ANTI-RECYCLE TIMER ..........................................................................................................................171
ANTI-COINCIDENCE TIMER ..................................................................................................................171
EVAPORATOR PUMP CONTROL & YORK ..........................................................................................171
HYDRO KIT PUMP CONTROL ...............................................................................................................171
EVAPORATOR HEATER CONTROL .....................................................................................................171
PUMPDOWN CONTROL .........................................................................................................................171
STANDARD CONDENSER FAN CONTROL .........................................................................................171
LOAD LIMITING .......................................................................................................................................175
COMPRESSOR RUN STATUS ...............................................................................................................175
ALARM STATUS ......................................................................................................................................175
BAS/EMS TEMPERATURE RESET USINGA VOLTAGE OR CURRENT SIGNAL ...........................176
SECTION 9 – SERVICE AND TROUBLESHOOTING ................................................................................177
CLEARING HISTORY BUFFERS ...........................................................................................................177
SERVICE MODE ......................................................................................................................................177
SERVICE MODE – OUTPUTS ................................................................................................................177
SERVICE MODE – CHILLER CONFIGURATION .................................................................................178
SERVICE MODE – ANALOG & DIGITAL INPUTS ...............................................................................178
CONTROL INPUTS/OUTPUTS ..............................................................................................................179
MICROBOARD LAYOUT ........................................................................................................................180
CHECKING INPUTS AND OUTPUTS ....................................................................................................181
Digital Inputs ......................................................................................................................................181
Analog Inputs – Temperature ...........................................................................................................181
Outside Air Sensor ............................................................................................................................181
Liquid & Refrigerant Sensor Test Points ........................................................................................182
Analog Inputs – Pressure .................................................................................................................183
Digital Outputs ...................................................................................................................................184
OPTIONAL PRINTER INSTALLATION .................................................................................................185
Parts ....................................................................................................................................................185
Assembly and Wiring ........................................................................................................................185
Obtaining a Printout ..........................................................................................................................185
TROUBLESHOOTING .............................................................................................................................186
TABLE OF CONTENTS (CONT’D)