Honeywell CHRONOTHERM T8621A - Manual (Page 29)

29 68-0058—1
T8621A,C,D
TROUBLESHOOTING
AUTOMATIC THERMOSTAT HEATING
OR COOLING TEMPERATURE CAN
NOT BE SET CLOSER THAN 3 F
O
THERMOSTAT MOUNTED
INCORRECTLY ON BASE
BATTERIES ARE INCORRECTLY
INSTALLED
SYMPTOM POSSIBLE CAUSE ACTION
NO ac POWER TO THERMOSTAT CHECK POWER TO FURNACE OR AIR CONDITIONER.
–ON-OFF SWITCH
–FUSE OR CIRCUIT BREAKER
–LOOSE 24 V CONNECTION
–AT THERMOSTAT
–AT FURNACE /AIR CONDITIONER
–INCORRECT WIRING
–CHECK WIRING DIAGRAM
FURNACE OR AIR CONDITIONER
WON'T OPERATE
NO ac POWER TO THERMOSTAT CHECK POWER TO FURNACE OR AIR CONDITIONER.
–ON-OFF SWITCH
–FUSE OR CIRCUIT BREAKER
–LOOSE 24 V CONNECTION
–AT THERMOSTAT
–AT FURNACE /AIR CONDITIONER
–INCORRECT WIRING
–CHECK WIRING DIAGRAM
THERMOSTAT INOPERATIVE CONDUCT SELF-TEST; SEE CHECKOUT.
PRESENT SETTING TOO LOW/HIGH
ADJUST TEMPERATURE BY PUSHING WARMER/
COOLER KEYS.
SYSTEM SWITCH ON THERMOSTAT
IN WRONG POSITION
RESET THERMOSTAT SYSTEM SWITCH.
WAIT 5 -10 MIN. OR USE SELF-TEST IN THERMOSTAT.
SEE CHECKOUT. MINIMUM-OFF TIMES IN THERMOSTAT
IN OPERATION ON COOLING
INCORRECT WIRING CHECK CIRCUIT DIAGRAM.
FURNACE OR AIR CONDITIONER
INOPERATIVE
CONSULT FURNACE OR AIR CONDITIONER
INSTRUCTIONS.
PARTIAL DISPLAY INOPERATIVE THERMOSTAT REPLACE THERMOSTAT.
CHECK THAT HEAT OR COOL SYSTEM POWER IS ON. NO POWER TO THERMOSTAT NO DISPLAY
SEE INSTALLATION INSTRUCTIONS FOR CORRECT
MOUNTING.
PRESENT SETTING APPEARS
INACCURATE
THERMOSTAT IS IN RECOVERY MODE
• NORMAL OPERATION THERMOSTAT TURNS ON
HEATING/COOLING EARLY TO MEET TEMPERATURE
SETTING AT PROGRAMMED TIMES.
• RECOVERY CAN BE ENDED BY PUSHING WARMER/
COOLER KEYS.
ROOM TEMPERATURE DISPLAY
APPEARS INACCURATE
THERMOSTAT TEMPERATURE NEEDS
TO BE ADJUSTED ON A REGULAR
BASIS
WARMER/COOLER KEYS BEING
USED TO ADJUST TEMPERATURE
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.
REPROGRAM ACCORDING PROGRAMMING INSTRUCTIONS
(MAKE SURE BATTERIES ARE INSTALLED). PROGRAMMING HAS BEEN LOST
BECAUSE OF A POWER OUTAGE DISPLAY FLASHES DURING
OPERATION
DISPLAY FLASHES WHILE
PROGRAMMING
IMPROPER PROGRAM SEQUENCE
PROGRAM IS LOST DUE TO POWER
OUTAGE OR DISPLAY GOES BLANK
WHEN POWER IS TURNED OFF
BATTERIES ARE DEAD
• THERMOSTAT IS CONTROLLED BY TEMPERATURE
SENSED AT REMOTE SENSOR LOCATION.
• CHECK TEMPERATURE AT REMOTE SENSOR LOCATION.
• MAKE SURE WIRING FROM THERMOSTAT LOCATION TO
REMOTE SENSOR LOCATION IS IN GOOD CONDITION.
M5234
THERMOSTAT HAS SEPARATE
REMOTE-MOUNTED SENSOR
SET HEATING AND COOLING TEMPERATURES 3 F OR
MORE APART. O
ROOM TEMPERATURE DISPLAY
IS 32
˚ F
Troubleshooting