Troubleshooting - Honeywell CHRONOTHERM T8624C User Manual

SYMPTOM
ROOM TEMPERATURE DISPLAY
˚
IS 32 F.
FURNACE OR AIR CONDITIONER
WON'T OPERATE.
PARTIAL DISPLAY
NO DISPLAY
PRESENT SETTING APPEARS
INACCURATE.
CANNOT TEMPORARILY OVERRIDE
BOTH HEATING AND COOLING
SETTINGS IN AUTO MODE.
THERMOSTAT TEMPERATURE NEEDS
TO BE ADJUSTED ON A REGULAR
BASIS.
PROGRAM IS LOST DUE TO POWER
OUTAGE OR DISPLAY GOES BLANK
WHEN POWER IS TURNED OFF.
DISPLAY FLASHES WHILE
PROGRAMMING.
DISPLAY FLASHES DURING
OPERATION.
POSSIBLE CAUSE
NO ac POWER TO THERMOSTAT
NO ac POWER TO THERMOSTAT
THERMOSTAT INOPERATIVE
PRESENT SETTING TOO LOW/HIGH
SYSTEM SWITCH ON THERMOSTAT
IN WRONG POSITION.
MINIMUM-OFF TIMES IN THERMOSTAT
IN OPERATION ON COOLING
INCORRECT WIRING
FURNACE OR AIR CONDITIONER
INOPERATIVE
INOPERATIVE THERMOSTAT
NO POWER TO THERMOSTAT
THERMOSTAT MOUNTED
INCORRECTLY ON BASE.
THERMOSTAT IS IN RECOVERY
MODE.
NOT USING PRESENT SETTING KEY.
WARMER/COOLER KEYS BEING
USED TO ADJUST TEMPERATURE
BATTERIES ARE INCORRECTLY
INSTALLED.
BATTERIES ARE DEAD.
IMPROPER PROGRAM SEQUENCE
AUTOMATIC THERMOSTAT HEATING
OR COOLING TEMPERATURE CAN
O
NOT BE SET CLOSER THAN 3 F.
PROGRAMMING HAS BEEN LOST
BECAUSE OF A POWER OUTAGE.
21

TROUBLESHOOTING

ACTION
CHECK POWER TO FURNACE OR AIR CONDITIONER.
–ON-OFF SWITCH
–FUSE OR CIRCUIT BREAKER
–LOOSE 24V CONNECTION
–AT THERMOSTAT
–AT FURNACE /AIR CONDITIONER
–INCORRECT WIRING
–CHECK WIRING DIAGRAM
CHECK POWER TO FURNACE OR AIR CONDITIONER.
–ON-OFF SWITCH
–FUSE OR CIRCUIT BREAKER
–LOOSE 24V CONNECTION
–AT THERMOSTAT
–AT FURNACE /AIR CONDITIONER
–INCORRECT WIRING
–CHECK WIRING DIAGRAM
CONDUCT SELF-TEST; SEE CHECKOUT.
ADJUST TEMPERATURE BY PUSHING WARMER/
COOLER KEYS.
RESET THERMOSTAT SYSTEM SWITCH.
WAIT 5 -10 MIN. OR USE SELF-TEST IN THERMOSTAT.
SEE CHECKOUT.
CHECK CIRCUIT DIAGRAM.
CONSULT FURNACE OR AIR CONDITIONER
INSTRUCTIONS.
REPLACE THERMOSTAT.
CHECK THAT HEAT OR COOL SYSTEM POWER IS ON.
SEE INSTALLATION INSTRUCTIONS FOR CORRECT
MOUNTING.
• NORMAL OPERATION THERMOSTAT TURNS ON
HEATING/COOLING EARLY TO MEET TEMPERATURE
SETTING AT PROGRAMMED TIMES.
• RECOVERY CAN BE ENDED BY PUSHING WARMER/
COOLER KEYS.
PRESS AND HOLD DOWN PRESENT SETTING KEY TO
ALTERNATE BETWEEN HEATING AND COOLING SETTINGS.
REPROGRAM THERMOSTAT TO MAKE PERMANENT
CHANGE IN PROGRAM. WARMER/COOLER KEYS ARE
TEMPORARY UNLESS PERIOD KEY IS PRESSED FIRST.
REMOVE AND REPLACE PER MARKINGS ON THERMOSTAT.
REPLACE BATTERIES.
CHECK PROGRAMMING INSTRUCTIONS FOR CORRECT
PROGRAM SEQUENCE.
SET HEATING AND COOLING TEMPERATURES 3 F OR
MORE APART.
REPROGRAM ACCORDING PROGRAMMING INSTRUCTIONS
(MAKE SURE BATTERIES ARE INSTALLED).
T8624C,D
O
M5234A
68-0134