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Installation Instructions for
Heating & Cooling
Digital Model 850
5/1/1 Day Programmable
Thermostat
CONTENTS
Preparations.................................................. 1
Thermostat Details ........................................ 1
Removing Old Thermostat ............................ 1
Mounting and Wiring ..................................... 2
Check Thermostat Operation ........................ 4
Specifications ................................................ 7
Troubleshooting ............................................ 7
PREPARATIONS
THERMOSTAT DETAILS
REMOVING OLD THERMOSTAT
Before removing wires from old thermostat’s switching subbase,
label each wire with the terminal designation it was removed from.
1. Remove Old Thermostat: A standard heat/cool thermostat
consists of three basic parts:
a. The cover, which may be either a snap-on or hinge type.
b. The base, which is removed by loosening all captive screws.
c. The switching subbase, which is removed by unscrewing
the mounting screws that hold it on the wall or adaptor plate.
2. Shut off electricity at the main fuse box until installation is
complete. Ensure that electrical power is disconnected.
3. 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.
4. Identify each wire attached to the old thermostat using the
labels enclosed with the new thermostat.
5. Disconnect the wires from the old thermostat one at a time. DO
NOT LET WIRES FALL BACK INTO THE WALL.
6. Install new thermostat using the following procedures.
To prevent electrical shock and/or equipment damage,
disconnect electrical power to the system at the main
fuse or circuit breaker until installation is complete.
CAUTION
!
PART NO. 37-6295B
Replaces 37-6295A
0514
Failure to follow and read all instructions carefully
before installing or operating this control could cause
personal injury and/or property damage.
Assemble tools required as shown below.
YOUR THERMOSTAT REPLACES
1
2
3
WIRE CUTTER/STRIPPER
HAND OR POWER
DRILL WITH 3/16 INCH
DRILL BIT, IF NEEDED
FLAT BLADE SCREWDRIVER
SPIRIT LEVEL OR PLUMB BOB AND LINE (OPTIONAL)
Description 850
Standard Heat & Cooling Systems – 4 or 5 wires Yes
Standard Heat Only Systems Yes
Millivolt Heat Only Systems – Floor or Wall Furnaces Yes
Standard Central Air Conditioning Yes
Gas or Oil Heat Yes
Electric Furnace Yes
Hydronic (Hot Water) Zone Heat – 2 Wires Yes
Hydronic (Hot Water) Zone Heat – 3 Wires No
Heat Pump (No Aux or Emergency Heat) Yes
Heat Pump (with Aux or Emergency Heat) No
Baseboard Electric Heating or Line Voltage (120 or 240 volt) No
Mounting
holes
Mounting
holes
Electric/Gas
switch
Screw anchors
Figure 1. Thermostat base
White-Rodgers is a division
of Emerson Electric Co.
www.white-rodgers.com