27
68-0076—1
Press and release to return to normal
operation.
CHECKING THE PROGRAM
TIMES AND TEMPERATURES
If desired, check all the stored settings
without affecting the permanent program.
Press and hold until the desired period shows
on the display. The start time and tempera-
ture setting will appear on the display.
Press and release to display the next day
time and temperature for that period.
Press and release to return to normal opera-
tion.
CHECKING THE CURRENT
TEMPERATURE SETTING
Press a single key to compare actual
room temperature to the setting at any
time.
Press and release. The display will show
the current temperature setting for several
seconds, then revert to the room tempera-
ture.
During recovery from energy savings, the
setting displayed will not match the pro-
grammed setting. This is because the ther-
mostat gradually changes the temperature
setting during recovery to provide maxi-
mum comfort combined with most effi-
cient use of the heating or cooling equip-
ment.
Operation
The T8611M Thermostat provides automatic control of
multistage heat pump systems with up to three stages of
heat and up to two stages of cool. The first heat stage is the
heat pump and the last stage is electric, gas, or oil auxiliary
heat. T8611M provides automatic changeover from heat
to cool or cool to heat.
ADAPTIVE INTELLIGENT RECOVERY™
OPERATION
Adaptive Intelligent Recovery™ is the Honeywell trade-
mark for the way the T8611 controls the heating and
cooling equipment during recovery from an energy sav-
ings setting to a comfort setting. During recovery, the
control point changes gradually rather than jumping from
the energy savings setting to the comfort setting all at once.
This provides additional energy savings.
When Adaptive Intelligent Recovery™ is used in the
heating mode, the control point raises gradually, maximiz-
ing the use of the more economical heat pump to bring the
sensed temperature to the desired comfort setpoint. This
minimizes the use of the typically more expensive auxil-
iary heat.
In both heating and cooling, the thermostat monitors
recovery each day and adjusts the next day recovery start
time. This ensures that the building is at the desired
temperature at the programmed time, regardless of the
outdoor temperature. Recovery time varies depending on
the weather conditions and the building heating/cooling
system.
The advantages are:
• The comfort setting is achieved at the programmed
time and maintained regardless of weather condi-
tions; occupants come home and wake up to com-
fort.
• Drafts from low temperature discharge air are mini-
mized during occupied periods.
• The thermostat automatically uses the more eco-
nomical heat pump as the primary heat source dur-
ing heat mode recovery, avoiding the use of the
expensive auxiliary heat.
• Comfort and energy savings can be achieved in both
heating and cooling.
• Reduces heat pump compressor cycling, extending
equipment life.
Use of Outdoor Thermostats
Because Adaptive Intelligent Recovery™ calls for aux-
iliary heat only when it is truly needed, it eliminates the
need for outdoor thermostat(s). If an outdoor thermostat is
used with T8611 and it is set close to the balance point, the
recovery time from energy savings will be prolonged
because the outdoor thermostat will prevent operation of
PERIOD
DAY
RUN
PROGRAM
M2751
SET
PT
HEAT
M2748
SET
PT
PM
FRI
NIGHT
HEAT
M2749
SET
PT
PM
SAT
NIGHT
HEAT
M2750
SET
PT
PM
FRI
EVENING
T8611M
OPERATING THE THERMOSTAT • OPERATION
PRESENT
SETTING
