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INSTALLATION
WARNING
!
Thermostat installation and all components of the
control system shall conform to Class II circuits per
the NEC code.
Remove Old Thermostat
A standard heat/cool thermostat consists of three basic parts:
1. The cover, which may be either a snap-on or hinge type.
2. The base, which is removed by loosening all captive screws.
3. The switching subbase, which is removed by unscrewing
the mounting screws that hold it on the wall or adapter
plate. Before removing wires from old thermostat,
label each wire with the terminal designation from
which it was attached. Disconnect the wires from the old
thermostat one at a time. Do not let wires fall back into
the wall.
Installing New Thermostat
1. Pull the thermostat body off the thermostat base. Forcing
or prying on the thermostat will cause damage to the unit.
2. Place base over hole in wall and mark mounting hole
locations on wall using base as a template.
3. Move base out of the way. Drill mounting holes. If you
are using existing mounting holes and the holes drilled
are too large and do not allow you to tighten base snug-
ly, use plastic screw anchors to secure the base.
4. Fasten base snugly to wall using mounting holes shown
in Figure 1 and two mounting screws. Leveling is for
appearance only and will not affect thermostat operation.
5. Connect wires to terminal block on base using
appropriate wiring schematic (see Figures 2 & 3).
WIRING CONNECTIONS
Refer to equipment manufacturers' instructions for specific
system wiring information. After wiring, see CONFIGURA-
TION section for proper thermostat configuration.
TERMINAL DESIGNATION DESCRIPTIONS
Terminal Designation
Description
W . . . . . . . . . Heat Relay
G . . . . . . . . . Fan Relay
RH . . . . . . . . . Power for Heating
RC . . . . . . . . . Power for Cooling
C . . . . . . . . . Common wire from secondary side of cooling
system transformer or heat only system transformer
Figure 2 –
Two Transformer System
System
Malfunction
Switch
Low
Optional (Heat Pump)
Voltage
Malfunction Indicator
System
Power
Changeover
Valve Cooling
Changeover
Valve Heating
Compressor
Contactor
NOTE: If continuous backlight or hardwired power
input are desired but do not function in both HEAT
and COOL modes, cut the heating transformer 24V
wires and tape off. Connect the neutral circuit
disconnected from the heating transformer to the
neutral circuit of the cooling transformer. Disconnect
the wire to the RH terminal and install a jumper
between RH and RC. Depending on the system
requirements, replace the cooling transformer with a
75VA class II transformer if needed.
2
2
CLASS II
TRANSFORMER
HEATING
NEUTRAL
24VAC
L
HOT
Heat
W
Relay
O
B
Fan
G
Relay
Y
RH
Remove
Jumper
RC
C
Optional
Common
HOT
Connection
24VAC
NEUTRAL
CLASS II
TRANSFORMER
COOLING
6. Push excess wire into wall and plug hole with a fire re-
sistant material (such as fiberglass insulation) to prevent
drafts from affecting thermostat operation.
7. Carefully line the thermostat up with the base and snap
into place.
Battery Location
2 "AA" alkaline batteries are included in the thermostat at
the factory with a battery tag to prevent power drainage.
Remove the battery tag to engage the batteries.
To replace batteries, set system to OFF, remove thermostat
from wall and install the batteries in the rear along the top of
the thermostat (see Figure 1).
Figure 1 – Thermostat base and rear view of thermostat
Mounting
Hole
Place Level
across Mounting Tabs
(for appearance only)
Wiring diagrams shown are for typical systems and describe
the thermostat terminal functions.
Terminal Designation
L . . . . . . . . . . Heat pump malfunction indicator for
O . . . . . . . . . Changeover valve for heat pump energized
B . . . . . . . . . Changeover valve for heat pump energized
Y . . . . . . . . . Compressor Relay
Figure 3 – Single Transformer System
System
Malfunction
LINE IN
Switch
Low
Optional (Heat Pump)
Voltage
Malfunction Indicator
System
Power
Changeover
Energized in Cooling
Changeover
Energized in Heating
Compressor
Relay
LINE IN
NOTE: Heat Pump without Aux: If using L for MALF indicator, C
must be connected. Terminals W and Y must be jumpered and CR
HEAT must be selected to SL in Configuration Menu item 6.
Description
systems with malfunction connection
constantly in cooling
constantly in heating
Heat
W
Relay
L
Fan
O
G
Relay
*
Single transformer heat and cool
B
RH
systems require a jumper from
*
RC to RH for heat only systems.
Attach power to RH. For cool only
Y
RC
attach power to RC.
C
Optional 24VAC
Common
Connection
24 Volt
Common
24 Volt
Hot
TRANSFORMER
Mounting
Hole
Place Level
across Mounting Tabs
(for appearance only)
2 "AA" Batteries
LINE IN
CLASS II
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