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www.white-rodgers.com

   

4

  MOUNTING AND WIRING

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  non-absorbent  gloves,  take  up  the 
spilled mercury and place into a container which can be sealed. If a 
cell becomes damaged, the unit should be discarded.
Mercury must not be discarded in household trash. When the unit 
this product is replacing is to be discarded, place in a suitable con-
tainer. Refer to www.white-rodgers.com for location to send product 
containing mercury.

3

  REMOVING OLD THERMOSTAT

 

CONTINUED FROM FIRST PAGE

WARNING

!

Do not use on circuits exceeding specified voltage. Higher 
voltage will damage control and could cause shock or fire 
hazard.
Do not short out terminals on gas valve or primary control 
to test. Short or incorrect wiring will damage thermostat and 
could cause personal injury and/or property damage. 
Thermostat installation and all components of the system 
shall conform to Class II circuits per the NEC code.

Electric Heat or Single-Stage 

Heat Pump Systems

This thermostat is configured from the factory to operate a heat/cool, 
fossil fuel (gas, oil, etc.), forced air system. It is configured correctly 
for any system that DOES NOT require the thermostat to energize 
the fan on a call for heat. If your system is an electric or heat-pump 
system that REQUIRES the thermostat to turn on the fan on a call 
for heat, locate the 

ELEC/GAS switch (see fig. 1) and switch it to 

the 

ELEC position. This will allow the thermostat to energize the 

fan immediately on a call for heat. If you are unsure if the heating/
cooling system requires the thermostat to control the fan, contact a 
qualified heating and air conditioning service person.

Hydronic (Hot Water or Steam)  

Heating Systems

This thermostat is set to operate properly with a forced-air heating 
system. If you have a hydronic heating system (a system that heats 
with hot water or steam), you must set the thermostat to operate 
properly with your system.
The factory default setting is forced air heat. Clipping jumper W905 on 
the circuit board will produce a longer heating cycle which is normally 
for hot water or steam (hydronic) systems. Both settings produce a 
very accurate temperature control and can be set to your personal 
preference. As received, the thermostat cycles the system just under 
1˚F. With W905 clipped, the system cycles at approximately 1.5˚F.

Attach Thermostat Base to Wall

1.  Remove the packing material from the thermostat. Gently pull the 

body 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 appropri-

ate 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 mount-

ing screws. 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.

6.  Push  excess  wire  into  wall  and  plug  hole  with  a  fire-resistant 

material  (such  as  fiberglass  insulation)  to  prevent  drafts  from 
affecting thermostat operation.

Battery Location

This thermostat requires 2 “AAA” alkaline batteries to operate.

 

If 

 appears on the display, the batteries are low and 

should be replaced with fresh “AAA” Energizer

®

 alkaline batteries. 

The batteries are located on the back of the thermostat body (see 
fig. 1). 

CAUTION

!

Take care when securing and routing wires so they do not 
short to adjacent terminals or rear of thermostat. Personal 
injury and/or property damage may occur.

TERMINAL CROSS REFERENCE CHART

New Thermostat

Terminal Designation

Other Manufacturers’

Terminal Designation

RH
RC

G

W

Y

4

R
G

W

Y

RH

R
G

W

Y

M

V
F
H
C

R5

-

G

4

Y6

R

-

G

W

Y

*

*

*  These are four-wire, single-transformer systems.

    Factory installed jumper wire between the 

RH

    and 

RC terminals must remain in place.

Summary of Contents for White-Rodgers 1E78

Page 1: ...ical power to the system at the main fuse or circuit breaker until installation is complete PART NO 37 6599B Replaces 37 6599A 1026 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 WIRE CUTTER STRIPPER Base Back of Thermostat Body RC G RH Y O B W W904 W905 Moun...

Page 2: ... thermostat to operate properly with your system Thefactorydefaultsettingisforcedairheat ClippingjumperW905on the circuit board will produce a longer heating cycle which is normally for hot water or steam hydronic systems Both settings produce a very accurate temperature control and can be set to your personal preference As received the thermostat cycles the system just under 1 F With W905 clipped...

Page 3: ...re 7 Typical wiring diagram for heat pump with reversing valve energized in HEAT TRANSFORMER Reversing Valve RC O B JUMPER WIRE Compressor Contactor JUMPER WIRE Reversing valve is energized when the system switch is in the HEAT position Fan Relay If at any time during testing your system does not operate properly contact a qualified service person Fan Operation If your system does not have a G ter...

Page 4: ...ture F C CONVERTIBILITY The factory default setting is Fahr enheit Clipping W904 jumper on the circuit board see fig 1 will alter this feature to Celsius temperature setting LOW BATTERY INDICATOR If the 2 AAA alkaline batteries are low and should be replaced the display will be blank except for When the batteries are low pressing any but ton will cause the display to operate for ten seconds After ...

Page 5: ...ion to thermostat or system 3 Furnace Lock Out Condition Heat may also be 4 intermittent 5 Heating system requires service or thermostat requires replacement Re light pilot Set SYSTEM Switch to HEAT and raise setpoint temperature above room temperature Verify thermostat and system wires are securely attached Many furnaces have safety devices that shut down when a lock out condition occurs If the h...

Page 6: ... off more frequently but runs for a shorter time so there is no increase in energy use If you would like to increase the cycle time clip Jumper W 905 as mentioned in the instructions for Hydronic Heating Systems It is not possible to shorten the cycle time If an accept able cycle rate is not achieved as received or by clipping W 905 contact a local service person for additional suggestions Cooling...

Page 7: ...www white rodgers com NOTES ...

Page 8: ...White Rodgers is a division of Emerson Electric Co The Emerson logo is a trademark and service mark of Emerson Electric Co Homeowner Help Line 1 800 284 2925 www white rodgers com www emersonclimate com ...

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