Honeywell CHRONOTHERM III T8611M - Manual (Page 17)

17 68-0076—1
EM.HT. and CHECK LEDs. Applies to 2-stage
heat/2-stage cool system in which both heating
stages are compressorized.
Fig.10—T8611M Thermostat with EM.HT.-HEAT-
OFF-AUTO-COOL system and ON-AUTO fan
switching; EM.HT., CHECK, and AUX. HT. LEDs.
Applied to 2-stage heat/1-stage cool system.
ADJUSTING CYCLE RATE
To customize the thermostat last heating stage cycling
performance to various types of auxiliary heating equip-
ment, a cycle rate adjustment screw is provided on the back
of the thermostat to provide optimum savings and occupant
comfort.
NOTE: MOST APPLICATIONS WILL NOT REQUIRE
A CHANGE IN CYCLE RATE.
The room air temperature normally will vary slightly
from the comfort temperature setting with the cycling of
the heat pump or auxiliary heater.
The Stage 1 cycle rate of this thermostat is factory-set
for heat pumps and cannot be adjusted. The auxiliary heat
cycle rate can be adjusted by turning the cycle rate adjust-
ment screw on the back of the thermostat. See Fig. 11.
Increasing the cycle rate will reduce room temperature
swings when auxiliary heat is being used.
INSTALLING BATTERIES
Three AAA alkaline batteries are included to provide
backup to prevent program loss in case of power outage.
Install batteries in back of thermostat as shown in Fig. 12.
Without battery backup, the program will remain about
20 seconds in event of power loss.
IMPORTANT: When batteries are first installed, the
display will flash 1:00 PM and 32
°
. After a brief
delay, the display will flash 1:00 PM and room
temperature.
When the batteries are low, the display will flash REPL
BAT. Homeowner will have 20-30 seconds to install new
batteries after removing old batteries from back of thermo-
stat. After 20-30 seconds, it will be necessary to repro-
gram. REPL BAT indication will disappear within 5-10
minutes when thermostat is remounted on the powered
subbase.
IMPORTANT: For proper thermostat operation, always
replace dead batteries with new alkaline batteries.
If batteries are completely dead, the display will go
blank when the thermostat is removed from subbase. After
replacing the batteries, reprogramming will be necessary.
POWER OUTAGES
Backup batteries will hold the programming and keep
the display on during most power outages. Once the power
is restored, the system will resume normal operation.
If the display goes off when power is lost, either the
backup batteries need to be replaced or are not installed.
When power is restored, the display will flash 1:00 PM to
remind you to reprogram.
MOUNTING THE THERMOSTAT
With system switch set to OFF, hang the thermostat on
the tabs at the top of the subbase (Fig. 13A). Swing down
and press on lower edge until thermostat snaps in place
(Fig. 13B). Open cover and tighten the captive mounting
screws (Fig. 13C).
SETTING DAY AND TIME
Restore 24V power to the thermostat. Set present day
and time.
Press .
Press to set the current day. (Each press of the
DAY key advances the display one day.)
Press TIME or to set the current time.
If the display will not come on—
— check mounting of thermostat to subbase. If loose or
misaligned, remove thermostat and reinstall on the
subbase, making sure it is firmly attached.
— check to see that batteries are installed properly.
Fig. 11—Cycle rate adjustment.
Fig. 12—Battery placement.
T8611M
INSTALLATION
SET
PRESENT
DAY/TIME
DAY
BACK
AHEAD