T8775A,C THE DIGITAL ROUND™
TROUBLESHOOTING GUIDE
HEATING OR COOLING EQUIPMENT WILL NOT OPERATE.
PARTIAL DISPLAY
NO DISPLAY
TEMPERATURE DISPLAY IS
INCORRECT.
TEMPERATURE SETTINGS WILL NOT CHANGE. (EX: CANNOT SET THE HEATING HIGHER OR THE COOLING LOWER).
FAN DOES NOT OPERATE PROPERLY IN HEAT OR COOL MODES.
NO AC POWER TO THERMOSTAT.
THERMOSTAT INOPERATIVE.
PRESENT SETTING TOO LOW/HIGH.
SYSTEM SWITCH ON THERMOSTAT IN WRONG POSITION.
INCORRECT WIRING.
HEATING OR COOLING EQUIPMENT INOPERATIVE.
INOPERATIVE THERMOSTAT.
NO POWER TO THERMOSTAT.
THERMOSTAT MOUNTED INCORRECTLY ON WALLPLATE.
THERMOSTAT IS CONFIGURED FOR F OR C DISPLAY.
THE UPPER OR LOWER TEMPERATURE LIMITS WERE REACHED.
INCORRECT WIRING.
CHECK FUEL SWITCH POSITION.
HEATING OR COOLING EQUIPMENT INOPERATIVE.
•CHECK POWER TO HEATING AND COOLING EQUIPMENT
–
–FUSE OR CIRCUIT BREAKER
–LOOSE 24V CONNECTION:
–AT THERMOSTAT
–AT FURNACE/AIR CONDITIONER
–INCORRECT WIRING (SEE WIRING DIAGRAMS)
SEE CHECKOUT SECTION.
ADJUST TEMPERATURE BY TURNING DIAL CLOCKWISE OR
RESET THERMOSTAT SYSTEM SWITCH.
WAIT UP TO FIVE MINUTES FOR THE COOLING EQUIPMENT TO TURN ON.
CHECK WIRING DIAGRAMS.
CONSULT EQUIPMENT MANUFACTURER INSTRUCTIONS.
REPLACE THERMOSTAT.
•CHECK POWER TO HEATING AND COOLING EQUIPMENT
–
–FUSE OR CIRCUIT BREAKER
–LOOSE 24V CONNECTION:
–AT THERMOSTAT
–AT FURNACE/AIR CONDITIONER
–INCORRECT WIRING (SEE WIRING DIAGRAM)
SEE MOUNT THERMOSTAT TO WALLPLATE SECTION.
RECONFIGURE THE DISPLAY. SEE CUSTOMIZE THERMOSTAT SECTION.
CHECK THE TEMPERATURE SETPOINTS; TEMPERATURE SETTING RANGE IS 40 F TO 90 F (4.5 C TO 32 C) IN HEATING AND 45 F TO 99 F (7 C TO 37 C) IN COOLING.
CHECK WIRING DIAGRAMS.
SEE CUSTOMIZE THERMOSTAT SECTION.
CONSULT EQUIPMENT MANUFACTURER INSTRUCTIONS.
M19684
Automation and Control Solutions
Honeywell International Inc. | Honeywell |
1985 Douglas Drive North | 35 Dynamic Drive |
Golden Valley, MN 55422 | Scarborough, Ontario |
| M1V 4Z9 |
Printed in U.S.A. on recycled | www.honeywell.com/yourhome | |
paper containing at least 10% |
