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DIGITAL
THERMOSTAT
INSTALLATION
What You Need
This thermostat includes two #8 slotted screws and two wall anchors
for mounting. To install your thermostat, you should have the follow-
ing tools and materials.
• Slotted Screwdriver(s)
• Small Philips screwdriver
• Hammer
• Electric drill and 3/16” bit
• Two 1.5 V (AA) size alkaline batteries (included)
Remove Old Thermostat
CAUTION: Do not remove any wiring from existing thermostat
before reading the instructions carefully. Wires must be labeled
prior to removal.
IMPORTANT! Turn off the power to the furnace at the main
power panel or at the furnace.
Remove existing thermostat cover and thermostat. See Figure 1. Some
thermostats will have screws or other locking devices that must first
be removed. Once the wall mounting plate is exposed, look for wires.
If wires are not visible, they may be connected to the back of the
wallplate. Again, look for screws, tabs, etc. Some models have doors
that open to expose wires and mounting screws. See Figure 1.
Typical Home Thermostats
Mount Wallplate and Thermostat
• Remove the wallplate from your thermostat by pressing the release
tab on the bottom of the thermostat. See Figure 2.
Owners Manual
Model 43054
Congratulations!
Your new Climate Technology thermostat will provide years of reliable
service. Using this digital thermostat will provide more uniform com-
fort in your home through the seasons. Thank you for buying a Cli-
mate Technology product!
Please read this manual for complete instructions on installing and
operating your thermostat. If you require further assistance, call Cli-
mate Technology Technical Support at 1-800-676-7861 from 8am to
5pm Central Time.
IMPORTANT INFORMATION
1. This thermostat is designed to work on the following sys-
tems:
LCD Display:
Shows Room
Temperature, Set
Temperature, and
other feature
information as
required.
Low Battery
Indicator:
Flashes when
batteries need
to be replaced.
INDIGLO
®
night-
light: Backlights
display
automatically
with each key
press for easy
viewing.
System
Switch:
Selector
switch for
Heat, Cool,
and Off.
Fan Switch:
Fan switch for
Automatic or
Continuous
fan operation.
Battery
Compartment:
Front access allows
easy insertion of
two AA 1.5V
batteries.
Reset: Press with a
paper clip to reset the
thermostat and return
to power-up settings.
Up and Down Keys:
Keys for changing
the Temperature
setting. Also used
for adjusting the
Span.
Filter Change
Indicator: Flashes
when filter needs
to be checked.
Filter Key:
Resets the
filter
change
counter
to zero.
Front Doors:
Covers keys
and batteries
when not used
for neat
appearance.
Open with one
finger from top
or bottom.
• Oil - Fired Furnace
• Single Stage Heat Pumps - with no
auxiliary heat
• Electric Furnace
• Electric Air Conditioning
This thermostat will NOT control multistage heat pumps or 110/220 V
baseboard electric heating systems.
2. Temperature Range
This thermostat can be set between 45°F and 95°F (7°C and 35°C).
However, it will display room temperatures from 30°F to 99°F (0°C
and 37°C). “HI” will be displayed if the temperature is higher than
99°F (37°C), and “LO” will be displayed if the temperature is lower
than 30°F (0°C).
This thermostat will automatically cutoff in Heat mode if the tempera-
ture rises above 95°F (35°C), and automatically cutoff in Cool mode if
the temperature drops below 45°F (7°C).
3. Compressor Protection
This thermostat provides a 3.5 minute delay after shutting off the com-
pressor before it can be restarted. This feature will prevent damage to
your compressor caused by rapid cycling. It does not prevent a rapid
compressor restart due to short power outages.
4. Battery Warning
Two fresh AA alkaline batteries should provide well over one year of
service. However, when the batteries become drained, the Low Bat-
tery Indicator will flash on the display. When this message occurs,
install new alkaline batteries. You have approximately 1 minute to
change the batteries and keep the thermostat’s settings. Once the
batteries have become too low to ensure proper operation, your sys-
tem will be turned Off, and the display will be cleared except for flash-
ing Low Battery Indicator on the LCD display.
CAUTION: When only the battery icon flashes on the display,
the thermostat is shut down, and your system will no longer
operate. In this condition, there is no temperature control of
your dwelling.
NOTE: The INDIGLO
®
night-light will not function when the thermo-
stat is in low battery condition.
NOTE: If you plan to be away from the premises over 30 days, we
recommend that you replace the old batteries with new alkaline bat-
teries prior to leaving.
FEATURES
• Gas - Standing Pilot
• Gas - Electronic Ignition
• Gas - Fired Boilers
• Gas - Milivolt Systems
• Oil - Fired Boilers
Figure 1
Wire Labeling
• Each wire coming from the wall to the existing thermostat is con-
nected to a terminal point on that thermostat. Each of these termi-
nal points is usually marked with a code letter as shown in Table A
below.
• Note that this thermostat has multiple function terminals that allow
Single-Stage Heat Pump capability. Standard systems use: Rh, Rc,
G, Y, W. [Single-Stage Heat Pumps use: R, Y, G, and O or B.] Table A
below shows the multiple functions of the terminals. Use the termi-
nals that match your system.
• The number of wires in your system can be as few as two (for heat
only systems), as many as eight, or any number in between. If you
follow the labeling procedures correctly, you do not have to be con-
cerned about how many wires there are.
• There is often no terminal marking on the existing thermostat of
two wire, heat only systems. Just connect either of the wires to the
RH terminal, then connect the other wire to the W terminal to com-
plete the circuit.
• IMPORTANT! BEFORE DISCONNECTING ANY WIRES, APPLY THE SELF-
ADHESIVE LABELS PROVIDED TO THE WIRE AS SHOWN IN TABLE A
BELOW. (For example, attach the label marked W to the wire that
goes to the W or H terminal on your existing thermostat.) IGNORE
THE COLOR OF THE WIRES since these do not always comply with
the standard.
• After labeling wires, disconnect them from the existing thermostat
terminals.
• Remove existing wallplate. To make sure wires do not fall back into
wall opening, you may want to tape them to the wall.
• If hole in wall is larger than necessary for wires, seal this hole with
insulating material so that no hot or cold air can enter the back of
the thermostat from the wall. This air could cause a false thermo-
stat reading.
Table A
Wall Mounting Plate
Thermostat
Cover
Wall Mounting Plate
Thermostat
Cover
NOTE: Do not connect a “Common” wire (sometimes labeled “C”) to
any terminal on this thermostat. Tape up the wire and do not use. This
wire provides electricity to non-battery powered thermostats.
If the code letter on
your existing
thermostat is
then mark the
wire with
label shown
and connect to
thermostat terminal
shown
RH, R, VR or 4
24 Volt
- or -
B
Reversing Valve operating in Heat mode.
(Single Stage Heat Pumps ONLY.)
RC, VC
24 Volt Cool
- or -
O
Reversing Valve operating in Cool mode.
(Single Stage Heat Pumps ONLY.)
G or F
Fan
Y, Y1, C or M
Air Conditioning Compressor
- or -
Single Stage Heat Pump
Compressor
W or H
Heating
R
24 Volt
(Single Stage Heat Pumps ONLY.)
Figure 2
• Position wallplate on wall and pull existing wires through large open-
ing. Then level for appearance. Mark holes for plastic anchors pro-
vided, if your existing holes do not line up with those on the wallplate.
• Drill holes with 3/16” bit and gently tap anchors into the holes until
flush with wall.
• Reposition wallplate to wall, pulling wires through large opening.
Insert mounting screws provided into wall anchor and tighten. See
Figure 3.
Figure 3
NOTE: 5-wire Systems
If your thermostat has one wire marked R or Rh (2, 3, or 4-wire system),
then leave the jumper wire between the Rh and Rc terminals on the
wallplate. Otherwise, if you have separate Rh and Rc wires (5-wire
system), then remove the jumper wire between the Rh and Rc termi-
nals.
Connect Wires and Mount Thermostat to Wallplate
• Match and connect the labeled wires to the appropriate coded ter-
minal screws on the wallplate. (See Figure 4, 5.) Ignore any wires
which may be present, but which were not connected to the old
thermostat.
Figure 4 Figure 5
• Refer to the Wiring Diagrams below to be sure your system is wired
correctly.
• If your system is a single stage heat pump and uses an O or B wire,
you must move the System Selector switch inside the thermostat to
the Heat Pump position. If you have a normal furnace or electric
system, leave the switch in the Standard position. Refer to the Sys-
tem Selector section on the back for more information on this switch.
• Be sure to tighten the terminal screws securely, otherwise a loose
wire could cause operational problems with your system or thermo-
stat.
• Push excess wire back into the hole to prevent interference when
installing the thermostat to the wallplate.
• Make sure the System Switch is set to OFF, and the Fan Switch is set
to AUTO.
• Insert the tabs on top of the thermostat body into the slots at the
top of the wallplate. Press the bottom of the thermostat body into
the snap on the bottom of the wallplate. Refer to Figure 2. (NOTE:
Do not force the thermostat onto the wallplate, as the terminal pins
may be damaged. If it does not snap properly, the thermostat may
not work.)
• Insert the two AA size alkaline batteries, observing the polarity
marked inside the battery compartment.
• Switch on the main power at the panel or furnace.