T8112D PROGRAMMABLE THERMOSTAT
68-0206
7

To check the current temperature setting:

Press the Run Program key. (When using TEMPORARILY
CHANGE or HOLD, pressing this key will cancel the change
or hold.)

To check the programs:

1. Press the Schedule key repeatedly to see each time
and temperature.
2. Press the Run Program key.

To cancel a program:

1. Press the Schedule key until the program to cancel
appears
2. Press both the Time keys ▲ and ▼ together.

To permanently change a program:

Repeat the steps in the Heating Program or Cooling Program
section as applicable.

To return to the normal program:

Press the Run Program key.
HeatCool Off
M1703
Auto On
M1705
HeatCool Off
M1704
Auto On
M1705
Auto On
M1705
HeatCool Off
M1707
Temp
Temp
Temp
Temp
CHECKOUT AND SETTINGS
After the thermostat is mounted on the mounting plate, check operation as follows:

Fan Switch

FAN AUTO: Normal setting for most homes. A
single-speed fan turns on automatically with
the air conditioner or furnace. A two-speed fan
usually runs on high with the air conditioner
and on low with the furnace.
FAN ON: The fan runs continuously. Use for
improved air circulation during special
occasions or for more efficient electronic air
cleaning.

System Switch

COOL: The thermostat controls the air
conditioning system.
OFF: Both the heating and air conditioning
systems are off.
HEAT: The thermostat controls the heating
system.
Auto On
M1705
Auto On
M1706
HeatCool Off
M1704
HeatCool Off
M1707
HeatCool Off
M1703
Heating
Do
not
check the heating system operation by jumpering the thermostat terminals at the primary control
such as the gas valve, zone valve, or oil burner control. This will damage the thermostat.
Move the system switch to HEAT and the fan switch to AUTO.
Press the TEMP key until the setting is about 10°F (6°C) above the room temperature. After a short
delay, the heating should start and the fan should run (immediately if fan operation switch is set in
E position).
Press the TEMP key until the setting is about 10°F (6°C) below the room temperature. The heating
equipment should shut off.
Cooling
To avoid possible compressor damage, do not operate the cooling system when the outside temperature
is below 50°F (10°C). See the compressor manufacturer instructions for further information.
NOTE: When the cooling setting is changed, the thermostat can delay up to five minutes before turning
on the air conditioner to protect the compressor.
Move the system switch to COOL and the fan switch to AUTO.
Press the TEMP key until the setting is about 10°F (6°C) below room temperature. The cooling
equipment and fan should start.
Press the TEMP key until the setting is about 10°F (6°C) above the room temperature. The cooling
equipment and fan should stop.
Move the system switch to OFF with the fan switch remaining at AUTO. The system and fan should be
off.