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6320364-UUM-B-0423
Types of thermostat
You may have either a manual change-over thermostat or a program-
mable electronic thermostat.
• Manual change-over thermostat: Manual change over means
that you must manually position the comfort switch every time
you want to switch between cooling and heating operation.
• Programmable electronic thermostat: The computerized elec-
tronic thermostat is a sophisticated electronic version of a manual
change-over thermostat. This thermostat includes features that
allow set-back temperature variations for periods of sleep or while
you are away during the day, allowing you to make energy sav-
ings. The thermostat also features a digital clock.
See System operation for more information about how your system
operates with each type of thermostat.
Indoor circulating blower settings
Use the fan switch on the thermostat to choose how the indoor circulat-
ing blower operates:
• AUTO: If you set the fan switch to the AUTO position, the indoor
circulating blower runs intermittently as required for either heating
or cooling. The indoor circulating blower shuts off when there is
no heating or cooling operation. This option has the lowest oper-
ating cost. If you purchased one of our residential thermostats,
they may have an intelligent fan mode that continually circulates
the air in occupied mode or when you are at home, and can cycle
the indoor circulating blower in unoccupied mode or during the
night to further conserve energy.
• ON: If you set the fan switch to the ON position, the indoor circu-
lating blower operates continuously and does not shut off when
there is no heating or cooling operation. The cooling (AC) or heat-
ing (heat pump) systems operate as required by your thermostat
settings. This provides continuous air filtering and more even
temperature distribution to all conditioned spaces.
• Blower only operation: On moderate days, usually during spring
and fall, when neither heating nor cooling is required, you may
want to run only the indoor circulating blower to ventilate, circu-
late, and filter the air in your home or building. Set the comfort
control switch on the thermostat to the OFF position and set the
fan switch to the ON position. Make sure that you reset the
switches for normal operation.
Starting up the AC or HP system
Observe the application limitations shown in the unit Installation Manual
so your system delivers the best performance and requires minimum
service.
Note: For this procedure, the comfort control switch on the thermostat is
assumed to be set to the OFF position.
1. If the main power supply to the unit is off, set the appropriate dis-
connects to the ON position.
2. Set the comfort control switch on the thermostat to the COOL or
HEAT position as required.
3. Set the thermostat to the required temperature.
For cooling, the higher the setting, the lower the amount of energy
consumed. Federal guidelines recommend a setting of 78°F.
For heating, the lower the setting, the lower the amount of energy
consumed. Federal guidelines recommend a setting of 65°F or
lower.
NOTICE
If your cooling and heating temperature adjustments are separate, be
sure to set both.
4. Set the fan switch on the thermostat to the required position.
See Indoor circulating blower settings for more information.
2
Power failure
When events such as accidents or wind storms disrupt electrical power
supply to your house, set the thermostat to the OFF position.
System operation
It is important to understand how your system operates when you have
a manual change-over thermostat or an electronic thermostat. See
Types of thermostat for more information.
Manual change-over thermostat
To cool your home, set the comfort control switch on the thermostat to
the COOL position and set the thermostat to the required temperature.
When the indoor temperature rises above the selected temperature on
the thermostat, the system starts. The outdoor unit operates and the
indoor circulating blower circulates the cooled, filtered air. When the
room temperature is lowered to the selected temperature on the ther-
mostat, the system shuts off.
To heat your home, set the comfort control switch on the thermostat to
the HEAT position and set the thermostat to the required temperature. If
the system heat pump and the thermostat both have a call for heat,
power is supplied to the compressor and the outdoor fan motor. When
the indoor temperature drops below the selected temperature on the
thermostat, the system starts up. The heating system operates and the
indoor circulating blower circulates the filtered air. When the room tem-
perature is at the selected temperature on the thermostat, the system
shuts off. If the heat pump cannot meet the heating demand and the
unit is equipped with supplementary electric heat, the thermostat sends
a signal through the defrost control to energize the first stage of electric
heat.
To manage the indoor circulating blower operation, set the fan
switch on the thermostat as required. For continuous operation, set the
fan switch to the ON position. The indoor circulating blower continues to
operate regardless of whether heating or cooling operation is in prog-
ress. If you want the indoor circulating blower to shut off when your sys-
tem does, set the fan switch to the AUTO position. See Indoor
circulating blower settings for more information.
Electronic thermostat
The computerized electronic thermostat, when programmed, functions
automatically to operate the system. When the indoor temperature rises
above the higher (cool) setting, the outdoor unit operates and the indoor
circulating blower circulates the cooled, filtered air. When the room tem-
perature is lowered to the selected level, the system shuts off. The
indoor circulating blower either shuts off or runs continuously, depend-
ing on your selected fan setting. When the indoor temperature drops
below the lower (heat) setting, the heating system operates, and the
indoor circulating blower circulates the heated, filtered air. When the
indoor temperature rises to the selected setting, the system shuts off.
The indoor circulating blower either shuts off or runs continuously,
depending on your selected fan setting.
Maximizing operating efficiency
To maximize operating efficiency, take steps to conserve energy and
increase energy efficiency, and make sure that system maintenance
and servicing is performed as required.
Heating conservation
Adhere to the following:
• Keep storm windows and doors closed all year long, for the most
efficient operation. They help to insulate against heat and cold
and keep out dirt, pollen, and noise.
• Close drapes at night, keep fireplace dampers closed when not in
use, and run exhaust fans only when necessary. This helps you
to retain heated air.
• Keep lamps, televisions, or other heat producing sources away
from the thermostat. The thermostat senses the extra heat from
these sources, and can not maintain the selected indoor tempera-
ture.
Johnson Controls Ducted Systems
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