2
Mounting
Hole
Mounting
Hole
Place Level
across Mounting Tabs
(for appearance only)
Place Level
across Mounting Tabs
(for appearance only)
RC
C
G
W
RH
CLASS II
TRANSFORMER
COOLING
HOT
24VAC
NEUTRAL
LINE IN
Y
L
O
B
Optional (Heat Pump)
Malfunction Indicator
Low
Voltage
System
Power
Optional
Common
Connection
Fan
Relay
Heat
Relay
LINE IN
HOT
24VAC
NEUTRAL
CLASS II
TRANSFORMER
HEATING
Changeover
Valve Cooling
Changeover
Valve Heating
Compressor
Contactor
System
Malfunction
Switch
Remove
Jumper
2 "AA" Batteries
WIRING CONNECTIONS
Refer to equipment manufacturers' instructions for specific
system wiring information. After wiring, see CONFIGURA-
TION section for proper thermostat configuration.
Wiring diagrams shown are for typical systems and describe
the thermostat terminal functions.
WARNING
!
Thermostat installation and all components of the
control system shall conform to Class II circuits per
the NEC code.
INSTALLATION
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
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).
Figure 2 –
Two Transformer System
Figure 3 – Single Transformer System
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
2
Terminal Designation
Description
L . . . . . . . . . . Heat pump malfunction indicator for
systems with malfunction connection
O . . . . . . . . . Changeover valve for heat pump energized
constantly in cooling
B . . . . . . . . . Changeover valve for heat pump energized
constantly in heating
Y . . . . . . . . . Compressor Relay
Optional 24VAC
Common
Connection
RC
C
G
W
RH
CLASS II
TRANSFORMER
24 Volt
Hot
24 Volt
Common
LINE IN
Y
L
O
B
Optional (Heat Pump)
Malfunction Indicator
Fan
Relay
Heat
Relay
System
Malfunction
Switch
Single transformer heat and cool
systems require a jumper from
RC to RH for heat only systems.
Attach power to RH. For cool only
attach power to RC.
*
Low
Voltage
System
Power
Changeover
Energized in Cooling
Changeover
Energized in Heating
Compressor
Relay
*
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.
TERMINAL DESIGNATION DESCRIPTIONS
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.
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.
