Honeywell chronotherm t8621a Benutzerhandbuch

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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