White Rodgers EMERSON 1E78 User Manual

Page of 8
Installation Instructions for
Heating & Air Conditioning
1E78
5/2 Day Programmable Thermostat
CONTENTS
Preparations .................................................. 1
Thermostat Details ........................................ 1
Removing Old Thermostat ............................ 1
Mounting and Wiring ..................................... 2
Check Thermostat Operation ........................ 3
Programming your Thermostat ..................... 4
Specifications ................................................ 6
Troubleshooting ............................................ 6
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.
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. 37-6542B
Replaces 37-6542A
0434
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
Typical System Compatibility Chart
1E78
Standard Heat Only Two Wire Gas or Oil Fired Systems (24 volt)
Yes
Electronic Ignition Heat Only Two Wire Systems (24 volt)
Yes
Electronic Ignition Heat Only Gas or Oil Fired Systems (24 volt)
Yes
Standard Heat/Cool Systems (24 volt)
Yes
Heat/Cool Systems Electric Heat (24 volt)
Yes
Heat Only Electric Heat Systems (24 volt)
Yes
Cool Only Systems (24 volt)
Yes
Heat Pump Systems (No Aux or Emergency Heat)
Yes
Hot Water Zone Heat Only (Two Wire) Systems
Yes
Hot Water Zone Heat Only (Three Wire) Systems
No
Line Voltage Heating or Baseboard 110/240 Volt Systems
No
Millivolt Systems Floor or Wall Furnaces
Yes
12 VDC Mobile Home Application
Yes
Multistage Systems
No
Systems Exceding 30VAC, 1.5 Amp
No
Base
Back of 
Thermostat Body 
RC
ELEC
GAS
G
RH
Y
O
B
W
W905
W904
Elec/Gas
Switch
W903
Mounting
Hole
Mounting
Hole
Figure 1. Thermostat
W903 - clip to disable EMR feature
W904 - clip for Celcius display
W905 - clip for hydronic system
HAND OR POWER 
DRILL WITH 3/16 INCH 
DRILL BIT, IF NEEDED
FLAT BLADE SCREWDRIVER
White-Rodgers is a division 
of Emerson Electric Co.
www.white-rodgers.com