1
68-0058—1
T8621A,C,D
Chronotherm™ III Fuel
Saver Thermostats
C. H. • Rev. 8-92 • ©Honeywell Inc. 1992 • Form Number 68-0058—1
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Full seven-day program capability; different sched-
ules may be selected for every day.
■
Can be programmed in hand (with batteries in-
stalled) or on wall to provide up to four temperature
settings per day.
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Large digital clock (liquid crystal display) indi-
cates continuous time, day, current period and
room temperature.
■
Adaptive Intelligent Recovery™ brings room
temperature to programmed temperature at pro-
grammed time, maximizing comfort and energy
savings.
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Temperature control program maintains tempera-
ture within 1
°
F of setpoint.
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Temporary program override available by using—
— WARMER and COOLER keys
— SKIP next period key
— CHANGE to last period key
■
HOLD TEMP key provided for indefinite pro-
gram override (vacation/holiday).
■
Installer self-test and time delay override save
installation time.
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SYSTEM light-emitting diode (LED) indicates
system is energized.
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Models available with automatic or manual heat/
cool changeover.
■
Batteries included provide power to maintain
clock and memory during power failures.
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Switching subbase with wiring terminals included.
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Powered directly from control transformer, requir-
ing an extra (24V) wire to thermostat.
■
Fan operation switch included on back of SUPER
TRADELINE models to select either indepen-
dent or direct thermostat control of fan in heating.
■
Models available with separate sensor for remote
mounting.
CONTENTS
Specifications ............................................... 2
Ordering Information ................................... 2
Selection/Application ................................... 5
Installation ................................................... 7
Checkout ..................................................... 17
Programming the Thermostat .................... 19
Operating the Thermostat .......................... 25
Operation ................................................... 28
Troubleshooting ......................................... 29
Glossary ..................................................... 30
Table of Contents ....................................... 31
The T8621A,C,D Chronotherm III Program-
mable Fuel Saver Thermostats provide auto-
matic control of single or multistage heating/
cooling systems and offer users the highest
standard of comfort and convenience available
with energy savings.
