Wrap the wires around a pencil to prevent
them from falling into the wall.
Programmable Electronic Thermostat
If the hole in the wall is too big, insulate it
using a non-flammable material in order to
Installation and User Guide
avoid air draughts behind the thermostat.
2.2 Installing the New Baseplate
For a new installation, choose a location approximately 5 feet
(1.5 m) above the floor and on an inside wall. Avoid draughty
The RTH230B programmable thermostat can be used to control:
areas (top of staircase, air outlet, etc.), dead air spots (behind
• a gas, fuel oil or electric furnace - 2 or 3 wires
doors), direct sunlight or areas near concealed pipes or chim-
• a central air conditioner - 2 or 3 wires
• a hot water system with or without pump - 2 wires
• a millivolt system - 2 wires
• a central heating and cooling system - 4 or 5 wires
Note: These thermostats are not compatible with heat pumps or
Remove the thermostat faceplate.
Loosen the locking screw to separate the thermostat from its
baseplate (the screw cannot be completely removed).
Tilt the thermostat upwards.
• System operating mode selection: heat, cool or off
Mark and bore the appropriate mounting holes (or use the
• Fan operating mode selection: automatic or on (continuous)
existing holes). Insert the plastic anchors.
• Programmable heating and cooling cycle lengths: 10, 12, 15, 20
Pass the wires through the opening of the baseplate and fix the
or 30 minutes
baseplate to the wall using the screws provided.
• Temperature display in °F or °C
2.3 Connecting the Thermostat
• Battery replacement indicator
The connection of the new thermostat should be similar to that of
• 5-2 programming including:
the old thermostat; however, it can vary depending on the installa-
- Preprogrammed energy-saving schedule
- Early Start
- Temporary bypass
- Time display (12 h or 24 h)
Heating power supply
• Filter replacement indicator
Cooling power supply
2.1 Removing the Old Thermostat
Note: The red jumper wire between the Rc and Rh terminals must
IN ORDER TO AVOID ANY RISK OF ELECTRIC SHOCK, CUT
be removed in 2- or 5-wire installations. The jumper must be used in
POWER TO THE HEATING SYSTEM.
3- or 4-wire installations if you wish to use the mode selector switch
Remove the old thermostat to access the wires.
for the fan.
Warning: If the old thermostat was mounted onto an electrical box,
it was probably powered by 120/240 volts. In this case, this thermo-
stat cannot be used.
Identify and label each wire (with the corresponding letter on
the wire terminal) and remove them from the terminals.
If necessary, strip the end of each wire (maximum of 1/4 inch).