IOM 1178-1 / Page 3 of 16
Safety
WARNING
Wiring connections must be made in accordance with all
applicable electrical codes. Failure to read and follow all instruc-
tions carefully before installing or operating this control could
cause personal injury and/or property damage.
CAUTION
To prevent electrical shock, disconnect electric power to system
at main fuse or circuit breaker box until installation is complete.
NOTICE
If in doubt about whether your wiring is millivolt, line, or low volt-
age, have it inspected by a qualified heating and air condition
-
ing contractor or electrician.
Do not exceed the specification ratings.
All wiring must conform to local and national electrical codes
and ordinances.
This control is a precision instrument, and should be handled
carefully. Rough handling or distorting components could cause
the control to malfunction.
The remote sensors cannot be used with systems where power
interruptions are part of normal system operation.
NOTICE
MERCURY NOTICE
This product does not contain mercury. However, this product-
may replace a product that contains mercury. Mercury and
products containing mercury must not be discarded in house-
hold trash. Do not touch any spilled mercury. Wearing non-
absorbent gloves, clean up any spilled mercury and place in a
sealed container. For proper disposal of a product containing
mercury or a sealed container of spilled mercury, place it in a
suitable shipping container. Refer to www.thermostat-recycle.
org for location to send the product containing mercury.
Installation
Remove Old Thermostat
Before removing wires from old thermostat, mark wires for
terminal identification so the proper connections will be made
to the new thermostat.
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 snugly,
use plastic screw anchors to secure the base.
4. Fasten base snugly to wall using mounting holes shown
in
Figure 1 on page 4
and two mounting screws. Lev-
eling is for appearance only and will not affect thermostat
operation.
5. Connect wires to terminal block on base using appropri-
ate wiring schematic.
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). For best results, use a premium
brand
“
AA
”
alkaline battery such as Duracell® or Energizer®.
If the zone is going to be unoccupied for an extended period
(over 3 months) and
is displayed, the batteries should be
replaced before leaving.
Power Stealing Switches
The Power Stealing Switches (
Figure 1 on page 4
) should
be left in the
“
On
”
position for most systems. The information
in the following table details the thermostat power method
and switch options.
Table 8: Thermostat power method & switch position
Thermostat Power Method
Switch Position/Description
Battery Powered
, no 24-volt system
power available.
Switches “On”, thermostat runs on
batteries.
Hardwired with Battery Back-up
,
for 24-volt systems with common
connection from transformer to “C”
terminal on thermostat.
Switches
“On”
, thermostat runs on
power directly from transformer with
battery backup.
(Recommended application)
*
Battery Powered with Power
Stealing Assist
, for 24-volt systems
with no common connection from
transformer to “C” terminal on
thermostat.
Switches
“On”
, thermostat runs
on batteries and supplemental
power drawn through the heat or cool
circuit.
*Power Stealing Assist is very reliable to increase battery life,
but on a small number of heating or cooling systems with
high impedance electronic modules you may observe one of
the following conditions:
1. The fan may turn on with no call for heat or may not turn
off.
2. The water source heat pump may not turn off when the
call for heat ends.
3. The water source heat pump may not turn off when the
call for cool ends.
If the Power Stealing Assist method is not compatible with
your system, place the Power Stealing Switches to “Off”.
This cancels Power Stealing Assist, operates the thermostat
on batteries and corrects the condition.
