About Your New Thermostat - Honeywell RTHL3550 Owner's Manual

Description
Function Press the s or t button to
3 select your heating system
and fan operation
5 select your heating system
and optimize its operation
6 select your Stage 2 heating
system and optimize its
operation
12 select Manual or Auto
Changeover
14 select Fahrenheit or Celsius
temperature display
27 select maximum heat
temperature setting
28 select minimum cool
temperature setting

About your new thermostat

Your new Honeywell thermostat has been designed to give you many years of
reliable service and easy-to-use, push-button climate control.
Large, clear, backlit display is easy to read — even in the dark.
•
Displays both room temperature and temperature setting.
•
Removable battery holder for fast, easy replacement.
•
Built-in compressor protection.
•
Setting
0 Gas or oil heat: Use this setting if you have a gas or oil
heating system (system controls fan operation).
1 Electric heat: Use this setting if you have an electric
heating system (thermostat controls fan operation).
5 Gas or oil furnace: Use this setting if you have a
standard gas or oil furnace that is less than 90%
efficient.
9 Electric furnace: Use this setting if you have any type
of electric heating system.
3 Hot water or high-efficiency furnace: Use this setting
if you have a hot water system or a gas furnace of
greater than 90% efficiency.
1 Gas/oil steam or gravity system: Use this setting if
you have a steam or gravity heat system.
5 Gas or oil furnace: Use this setting if you have a
standard gas or oil furnace that is less than 90%
efficient.
9 Electric furnace: Use this setting if you have any type
of electric heating system.
3 Heat pump, hot water or high-efficiency furnace:
Use this setting if you have a hot water system or a gas
furnace of greater than 90% efficiency.
1 Gas/oil steam or gravity system: Use this setting if
you have a steam or gravity heat system.
0 Manual Changeover: (Heat/Off/Cool)
1 Automatic Changeover: (Heat/Off/Cool/Auto)
Automatically turns on heat or cool based on room
temperature.
CAUTION:
damage, do not use Auto Changeover if the
outside temperature drops below 50 ºF (10 ºC).
NOTE:
System maintains a minimum 3 ºF
difference between heat and cool settings.
0 Fahrenheit temperature display (°F)
1 Celsius temperature display (°C)
Maximum heat temperature setting (°F)
40 – 90
(4.5 to 31.5°C)
Minimum cool temperature setting (°F)
50 – 99
(10.5 to 37°C)
11
To avoid possible compressor