Honeywell T8090A User Manual
Heating or Cooling Thermostat
and Wallplate or
Heating/Cooling Thermostat and
Subbase
T8090A/191108A, Q682B
OWNER’S MANUAL
1 69-0574—2
69-0574-2
Welcome to the world of energy savings with your new Honeywell fuel saver thermostat. The
Honeywell name is your assurance of accurate control and reliable operation for years to come.
Your new thermostat will automatically lower and raise the temperature in your home one or
more times every 24 hours. This allows you to significantly lower your fuel costs, while awakening
(or returning home) to a comfortable temperature.
Read this manual to learn how to use your new thermostat.
Recycling Notice
M3375
This control contains mercury in a sealed tube. Do not place control in the trash at the end of
its useful life.
If this control is replacing a control that contains mercury in a sealed tube, do not place your
old control in the trash.
Contact your local waste management authority for instructions regarding recycling and the
proper disposal of this control, or of an old control containing mercury in a sealed tube.
If you have questions, call Honeywell Inc. at 1-800-468-1502.
69-0574—2 2
TABLE OF CONTENTS
Features Of Your Thermostat ........................................................................................................... 4
Setting The Temperature .................................................................................................................. 7
Inserting Clock Batteries ................................................................................................................... 8
Setting The Clock .............................................................................................................................. 9
Programming................................................................................................................................... 10
Troubleshooting .............................................................................................................................. 14
Servicing The Thermostat ............................................................................................................... 23
Cycle Rate Adjustment.................................................................................................................... 23
Thermometer Adjustment................................................................................................................ 24
Warranty.......................................................................................................................................... 27
3 69-0574—2
Features Of Your Thermostat
1 FLIP-UP COVER. Lift it up to set clock for
energy savings and normal temperature
periods.
2 THERMOSTAT COVER. Lift up and
remove to adjust heat anticipator.
3 THERMOMETER. Provides accurate room
temperature reading.
4 CLOCK. This clock provides a 24-hour
slotted dial to hold the programming pins.
5 CLOCK HANDS. Turn minute hand clock-
wise
to match the correct AM or PM
time to the time indicator.
6 TIME INDICATOR. Arrow head indicates
time for 24-hour dial.
7 PROGRAM INDEX WHEEL. Controls high
and low temperature at specific time of day
as set by program pins.
69-0574—24
8 TEMPERATURE SETTING LEVERS. Left
(blue mark) controls the low temperature,
right (red mark) controls the high
temperature.
1
3
2
M8726
9 PROGRAM PINS. Must be inserted into
24-hour clock dial slots to control program
index wheel.
10 PIN SLOTS. Located on 24-hour dial at
10-minute intervals for program pin
insertion.
11 MANUAL PROGRAM ADVANCE BUTTON.
Allows change from comfort to energy
savings setting and vice versa without
changing the program.
12 HEAT ANTICIPATOR SCALEPLATE.
Calibrated to match the heating system
current draw in amperes.
13 ANTICIPATOR SETTING LEVER. Must be
adjusted to match the heating system
primary control current.
14 MERCURY BULB AND BIMETAL
ELEMENT (2). Provide automatic temperature control by switching the heating or
cooling system on or off.
5
4
9
7
10
6
11
8
13
12
14
M8691
5 69-0574—2
15 191108AJ WALLPLATE. Provides mount-
ing base and wiring connections for
heating-only or cooling-only thermostat.
15
16 Q682B SUBBASE. Provides mounting
base, wiring connections and manual
switching control for heating/cooling
thermostat.
16
69-0574—26
FAN
O
B
R
W
G
Y
AUTO OFF
HEATON
M2421
COOL
M719
Setting The Temperature
For Heating:
Set the left lever (blue mark) to the energy
savings temperature you want when you are
sleeping or your home is unoccupied.
Set the right lever (red mark) to the temperature you want for normal comfort periods.
NOTE: You may override the time program by
setting both the red and blue levers to the
same temperature set point.
For Cooling:
Set the left lever (blue mark) to the temperature you want for normal comfort periods.
Set the right lever (red mark) to the energy
savings temperature you want when you are
sleeping or your home is unoccupied.
LOW TEMPERATURE
SETTING LEVER
(BLUE MARK)
12
8
7
9
6
10
5
1
4
1
3
12
1
9
2
3
2
3
1
12
1
4
1
10
5
6
9
7
8
6
50
50
607080
60 70 80
HIGH
TEMPERATURE
SETTING
LEVER
(RED MARK)
M1520
Fig. 1—Setting high and low
temperature levers.
7 69-0574—2
Inserting Clock Batteries
Power is supplied to the clock by the 24 Vac
transformer, by two AAA alkaline batteries
BATTERY LOCATION FOR
(2) AAA BATTERIES;
INSTALL WITH POSITIVE
ENDS UP
(included), or by the heating or cooling control
circuit. Backup batteries may be installed to
supply power to the clock if power is interrupted when using 24 Vac powering method.
Install batteries in thermostat as shown in
Fig. 2. Once a year or when batteries are dead,
replace with two new AAA alkaline batteries.
We recommend Energizer
®
batteries.
Fig. 2—Inserting clock batteries.
69-0574—28
M7188
Setting The Clock
Lift thermostat flip-up cover and you’ll find
the 24-hour program dial, slotted in 10-minute
increments. Adjust the clock to the current time
by moving the minute hand carefully in clockwise direction. DO NOT reverse the
minute hand.
When time is correctly set, the Time
Indicator Arrow (see Fig. 3) will point to the
correct time and corresponding daytime (light)
or nighttime (dark) band of the program dial.
Time ends, move the minute hand carefully in
a clockwise direction 23 hours. Do NOT
reverse the minute hand, or damage to timer
mechanism may occur.
MINUTE
HAND
EXAMPLE: For 11 PM, the time indicator arrow
will point directly to dark band. For 11 AM,
the arrow will point to light band on dial.
Daylight Savings Time
When Daylight Savings Time starts, move
the minute hand carefully in a clockwise
direction one hour. When Daylight Savings
TIME
INDICATOR
ARROW
M8561
Fig. 3—Setting the clock.
9 69-0574—2
Loading...