• Close to or in a frequently used room, preferably on an inside
Switch D - Intelligent Heat Staging Select
(Active on 2S models only)
• On a section of wall without pipes or duct work.
This switch converts a 2-speed heat pump thermostat with 1 stage
Thermostat should NOT be mounted:
of auxiliary heat into a 1-speed heat pump thermostat with 3 stages
of auxiliary heat for comfortable leaving air temperature. It
• Close to a window, on an outside wall, or next to a door leading
requires selected heaters with 2:1 ratio element sizes plus an FK,
to the outside.
FV, 40FKA fan coil. Refer to variable-speed fan coil literature for
• Exposed to direct light and heat from a lamp, sun, fireplace, or
other temperature-radiating object which may cause a false
OFF—for normal 2-speed operation. This is factory default.
• Close to or in direct airflow from supply registers and return-air
ON—for intelligent 3-stage heat with FK, FV, 40FKA fan coil.
Step 3—Install Thermostat
• In areas with poor air circulation, such as behind a door or in
Step 2—Set DIP Switches
Before installing thermostat, turn off all power to unit. There
There is a 4 section DIP switch within the thermostat which must
may be more than 1 power disconnect. Electrical shock can
be properly set by the installer. It is easiest to set these 4 switches
cause personal injury or death.
before the thermostat is mounted to the wall, so STOP and
1. Turn OFF all power to unit.
complete the following steps:
2. If an existing thermostat is being replaced:
1. Open hinged thermostat cover.
a. Remove existing thermostat from wall.
2. Remove cover completely by snapping it apart at hinge.
b. Disconnect wires from existing thermostat, 1 at a time. Be
3. Open thermostat by pressing back half of the right end of
careful not to allow wires to fall back into the wall.
plastic case inward while, at the same time, pulling front and
c. As each wire is disconnected, record wire color and
back halves apart at the right end. The 2 halves will swing
d. Discard or recycle old thermostat.
4. Snap hinge apart to completely separate the 2 halves.
NOTE: Mercury is a hazardous waste and MUST be disposed of
5. Switches are located in upper right corner of circuit board. To
change switch position, use corner of a small screwdriver to
slide switch to opposite position.
3. Open thermostat rear door (mounting base) to expose mount-
ing holes. The base can be removed to simplify mounting.
6. After switches have been set, do not reassemble the 2 halves.
Snap apart carefully at hinge to separate mounting base from
The rear plastic will be first mounted to wall.
remainder of thermostat.
Switch A - Zoning Select (Active on all models)
4. Route thermostat wires through large hole in mounting base.
This switch selects or defeats the 4 cycles per hour limit and a
Level mounting base against wall (for aesthetic value
5-minute compressor timeguard. These timers MUST be enabled
only—thermostat need not be leveled for proper operation)
for normal operation and disabled for zoning applications. (In
and mark wall through 2 mounting holes.
zoning applications the zone control center performs these timing
5. Drill two 3/16-in. mounting holes in wall where marked.
6. Secure mounting base to wall with 2 screws and anchors
OFF— for normal operation. This is the factory default.
provided, (additional anchoring holes available for more
ON—for zoned installations ONLY.
secure mounting if needed) making sure all wires extend
through hole in mounting base.
Switch B - Setback Recovery (Active on all models)
7. Adjust length and routing of each wire to reach proper
Selects between normal and smart recovery from setback. Normal
terminal and connector block on mounting base with 1/4 in. of
recovery changes to the new setpoint at the programmed time.
extra wire. Strip only 1/4 in. of insulation from each wire to
Smart recovery, which is active in heating mode only, starts earlier
prevent adjacent wires from shorting together when con-
and adjusts the setpoint slowly so that room temperature will arrive
at the programmed temperature at the programmed time.
8. Match and connect equipment wires to proper terminals of the
OFF—for smart recovery. This is the factory default.
connector blocks. (See Table 1, and Fig. 2 through 24.) Both
ON—for normal recovery.
R and C must be connected for proper thermostat operation.
Switch C - HP/AC Select (Active on HP and 2S models only)
Use to select between AC and HP installations. HP and 2S models
Improper wiring or installation may damage the thermostat.
have an extra relay to control the HP reversing valve. When a HP
Check to make sure wiring is correct before proceeding with
thermostat is placed in the AC mode, this extra relay is converted
installation or turning on unit.
to a second stage heat output. This allows thermostat control of
2-stage furnaces or 2-stage strip heat with AC systems. (AC mode
9. Push any excess wire into wall and against mounting base.
also uses W rather than Y for first-stage heat.)
Seal hole in wall to prevent air leaks. Leaks can affect
OFF—for HP applications. Extra relay controls reversing valve.
10. Snap hinge back together.
This is factory default.
ON—for AC applications. Extra output can be used for 2-stage
11. Close thermostat assembly making sure pins on back of circuit
board align with sockets in connector.