Thermostat
SERVICE MANUAL 12VDC WALL THERMOSTAT AIR CONDITIONING SYSTEMS ROOFTOP UNITS ONLY
! WARNING - SHOCK HAZARD!
TO PREVENT THE POSSIBILITY OF SEVERE PERSONAL INJURY, DEATH, OR EQUIPMENT DAMAGE DUE TO ELECTRICAL SHOCK, ALWAYS BE SURE THE POWER SUPPLY TO THE APPLIANCE IS DISCONNECTED BEFORE DOING ANY WORK ON THE APPLIANCE. THIS CAN NORMALLY BE ACCOMPLISHED BY SWITCHING THE BREAKER FOR THE AIR CONDITIONER TO OFF, DISCONNECTING ALL EXTERNAL ELECTRICAL CONNECTIONS AND CORDS, SWITCHING ON BOARD ELECTRICAL GENERATORS AND INVERTERS TO OFF, AND REMOVING THE CABLE FROM EACH POSITIVE TERMINAL ON ALL STORAGE AND STARTING BATTERIES.
DANGER
SOME DIAGNOSTIC TESTING MAY BE DONE ON ENERGIZED CIRCUITS. ELECTRICAL SHOCK CAN OCCUR IF NOT TESTED PROPERLY. TESTING TO BE DONE BY QUALIFIED TECHNICIANS ONLY The steps outlined in this manual are intended to guide the service technician through the process of correctly diagnosing a Coleman Mach series rooftop air conditioner with a remote wall thermostat control system. Page -1-
TABLE OF CONTENTS
PAGE I. II INTRODUCTION TO WALL THERMOSTATS ...................... 3
INTRODUCTION TO RELAYS ................................................. 5 HOW DO RELAYS FUNCTION ..................................... 5 CHECKING CEILING PLENUMS WITH INDIVIDUAL RELAYS ...................................................................................... 6 CHECKING CEILING PLENUMS WITH PRINTED CIRCUIT BOARDS .................................................................... 8 CHECKING THE THERMOSTAT OPERATION .......... 9 CHECKING THE PRINTED CIRCUIT BOARD OPERATION .................................................................. 10 DIAGNOSTIC FLOW CHARTS ............................................... 11
III
IV
V VI
WIRING DIAGRAMS ............................................................. 16
Page -2-
I. INTRODUCTION TO WALL THERMOSTATS All of the air conditioning functions are controlled by the wall mounted thermostat . These
! WARNING - SHOCK HAZARD!
TO PREVENT THE POSSIBILITY OF SEVERE PERSONAL INJURY, DEATH, OR EQUIPMENT DAMAGE DUE TO ELECTRICAL SHOCK, ALWAYS BE SURE THE POWER SUPPLY TO THE APPLIANCE IS DISCONNECTED BEFORE DOING ANY WORK ON THE APPLIANCE. THIS CAN NORMALLY BE ACCOMPLISHED BY SWITCHING THE BREAKER FOR THE AIR CONDITIONER TO OFF, DISCONNECTING ALL EXTERNAL ELECTRICAL CONNECTIONS AND CORDS, SWITCHING ON BOARD ELECTRICAL GENERATORS AND INVERTERS TO OFF, AND REMOVING THE CABLE FROM EACH POSITIVE TERMINAL ON ALL STORAGE AND STARTING BATTERIES.
DANGER
SOME DIAGNOSTIC TESTING MAY BE DONE ON ENERGIZED CIRCUITS. ELECTRICAL SHOCK CAN OCCUR IF NOT TESTED PROPERLY. TESTING TO BE DONE BY QUALIFIED TECHNICIANS ONLY The steps outlined in this manual are intended to guide the service technician through the process of correctly diagnosing a Coleman Mach series rooftop air conditioner with a remote wall thermostat control system. Page -1-
TABLE OF CONTENTS
PAGE I. II INTRODUCTION TO WALL THERMOSTATS ...................... 3
INTRODUCTION TO RELAYS ................................................. 5 HOW DO RELAYS FUNCTION ..................................... 5 CHECKING CEILING PLENUMS WITH INDIVIDUAL RELAYS ...................................................................................... 6 CHECKING CEILING PLENUMS WITH PRINTED CIRCUIT BOARDS .................................................................... 8 CHECKING THE THERMOSTAT OPERATION .......... 9 CHECKING THE PRINTED CIRCUIT BOARD OPERATION .................................................................. 10 DIAGNOSTIC FLOW CHARTS ............................................... 11
III
IV
V VI
WIRING DIAGRAMS ............................................................. 16
Page -2-
I. INTRODUCTION TO WALL THERMOSTATS All of the air conditioning functions are controlled by the wall mounted thermostat . These