INSTALLATION
REMOVE OLD THERMOSTAT
Screw anchors
1.Shut off electricity at the main fuse box until installation is complete. Ensure that electrical power is disconnected.
2.Remove the front cover of the old thermostat. With wires still attached, remove wall plate from the wall. If the old thermostat has a wall mounting plate, remove the thermostat and the wall mounting plate as an assembly.
3.Identify each wire attached to the old thermostat using the labels enclosed with the new thermostat.
4.Disconnect the wires from old thermostat one at a time. DO
NOT LET WIRES FALL BACK INTO THE WALL.
5.Install new thermostat using the following procedures.
ATTENTION!
This product does not contain mercury. However, this product may replace a unit which contains mercury.
Do not open mercury cells. If a cell becomes damaged, do not touch any spilled mercury. Wearing nonabsorbent gloves, take up the spilled mercury and place into a container which can be sealed. If a cell becomes damaged, the unit should be dis- carded.
Mercury must not be discarded in household trash. When the unit this product is replacing is to be discarded, place in a suitable container and return to
ELECTRIC HEAT OR SINGLE-STAGE
HEAT PUMP SYSTEMS
Read entire paragraph before setting electric heat switch. If you are unsure of your application, contact a qualified service person.
If you have a
If you must move the switch to the “ELECTRIC” position (to the left), use a small screwdriver or pencil.
ATTACH THERMOSTAT BASE TO WALL
1.Remove the packing material from the thermostat. Gently pull the cover straight off the base. Forcing or prying on the thermostat will cause damage to the unit. If necessary, move the electric heat switch (see ELECTRIC HEAT SYSTEMS, above).
2.Connect wires beneath terminal screws on base using appropriate wiring schematic (see figs. 2 through 7).
3.Place base over hole in wall and mark mounting hole locations on wall using base as a template.
4.Move base out of the way. Drill mounting holes.
5.Fasten base loosely to wall, as shown in fig. 1, using two mounting screws. Place a level against bottom of base, adjust until level, and then tighten screws. (Leveling is for appearance only and will not affect thermostat operation.) If you are using existing mounting holes, or if holes drilled are too large and do not allow you to tighten base snugly, use plastic screw anchors to secure subbase.
Mounting holes Electric/Gas
switch
Mounting holes
Figure 1. Thermostat Base
6.Push excess wire into wall and plug hole with a
HYDRONIC (HOT WATER OR STEAM)
HEATING SYSTEMS
This thermostat is set to operate properly with a
CHECK THERMOSTAT OPERATION
If at any time during testing your system does not operate properly, contact a qualified service person.
Turn on power to the system.
Fan Operation
If your system does not have a G terminal connection, skip to Heating System.
1.Move fan switch to ON position. The blower should begin to operate.
2.Move fan switch to AUTO position. The blower should stop immediately.
Heating System
1.Move SYSTEM switch to HEAT position. If the heating system has a standing pilot, be sure to light it.
2.Press 
to adjust thermostat setting above room tempera- ture. The heating system should begin to operate.
3.Press 
to adjust temperature setting below room tem- perature. The heating system should stop operating.
Cooling System
!CAUTION
To prevent compressor and/or property damage, if the outdoor temperature is below 50°F, DO NOT operate the cooling system.
1. Move SYSTEM switch to COOL position.
2
