Installation and User Guide
8
Pub. No. 18HD55D1-1C-EN 09/2020
Part No. 37-7790003
5. THERMOSTAT OVERVIEW
Before you begin using your thermostat, you should be familiar with
its features, display and the location/operation of the thermostat
buttons and switches.
5.1 Thermostat Operation
The Thermostat Buttons and
Switches
1
(Up arrow) Raises temperature setting.
2
(Down arrow) Lowers temperature setting.
3
FAN switch (
ON
,
AUTO
).
4
SYSTEM switch (
COOL
,
OFF
,
HEAT, EMER
).
The Display
5
Indicates a malfunction with the system.
6
Flame icon
( ) is displayed when the SYSTEM switch is in the
HEAT position. Flame icon ( ) is displayed flashing when 2nd-
stage heat (Aux or Emergency) is energized.
Snowflake icon
( ) is displayed (non-flashing) when the SYSTEM switch is in
the COOL position.
Snowflake
and
Flame icons
are displayed
(flashing) if the thermostat is in lockout mode to prevent the
compressor from cycling too quickly.
7
EMER
is displayed flashing when the system switch is in EMER
position.
8
Displays current temperature.
9
Displays currently programmed set temperature (this is blank
when SYSTEM switch is in the OFF position).
10
“BATT”
or
is displayed when 2 “AAA” batteries
are low and should be replaced.
2
3
4
Fan
Off
Heat
On Auto
Cool
Emer
1
5
8
10 9 6
8
7
6
Whenever
BATT
or
appears in the display, new premium brand AAA alkaline batteries should be installed. If the house will
be unoccupied for an extended period and
BATT
or
is displayed, install new batteries before leaving
