3 REMOVING OLD THERMOSTAT

CONTINUED FROM FIRST PAGE

ATTENTION! This product does not contain mercury. How- ever, 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 container. Refer to www.white-rodgers.com for location to send the product containing mercury.

4 MOUNTING AND WIRING

!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 sys- tem shall conform to Class II circuits per the NEC code.

1C20 (Heat Only Two Wire):

A.Mount base and adaptor plate: Mount base and adaptor plate (optional) to wall using screws provided (see Fig. 1).

B.Attach wires: Attach one wire to R and the other wire to W on base.

C.Skip to Step #5.

1C26 (Heating and Cooling):

A.Remove base from subbase: Loosen the three screws on the base and remove.

B.Mount switching subbase/adaptor plate: Use the screws provided to mount the subbase and adaptor plate (optional) to wall (see Fig. 1).

C.Attach wires to appropriate terminals:

For two wire systems (Heat Only or Cool Only). If you have a two-wireHeat Only system, attach one wire to RH and one to wire W. If you have a two-wireCool Only system, attach one wire to RC and one to wire to Y. Leave the factory installed jumper between RC and RH attached. Tighten any unused terminals securely.

If your system has more than two wires: Use the cross reference chart to determine correct wire connections. If you have a four-wire heat/cool system leave the factory installed jumper between RC and RH attached (see Fig 2.). If your system has five wires remove the factory installed jumper between RC and RH (see Fig 3.).

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 thermo- stat to energize the fan on a call for heat. If your system is an electric heat or heat-pump system that REQUIRES the ther- mostat to turn on the fan on a call for heat, remove the yellow factory-installed jumper wire from the Y terminal and connect

!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

 

Other Manufacturers’

 

Terminal Designation

 

Terminal Designation

 

RH

4

RH

M

*

*

R5

R

RC

R

R

V

-

-

G

G

G

F

G

G

W

W

W

H

4

W

Y

Y

Y

C

Y6

Y

*These are four-wire, single-transformer systems. Factory installed jumper wire between the RH and RC terminals must remain in place.

it to the A terminal. This will allow the thermostat to energize the fan immediately on a call for heat. If you are unsure if the heating system requires the thermostat to control the fan, contact a qualified heating and air conditioning service person. For single stage heat pump applications (no auxillary heat), install a short jumper wire (not included) across terminals W and Y. If the system has a reversing valve connection energized in Cooling, attach it to O. If the system has a reversing valve connection energized in Heating, attach it to B (see Fig. 4). This thermostat will not provide multi-stage heating or cooling.

D.Mount Thermostat Base: Gently push excess wire back into the wall opening and plug hole with a fire-resistant material, such as fiberglass insulation to prevent drafts from affecting thermostat operation. Mount the thermostat base to the sub- base using the three captive screws on the thermostat base. (See Fig. 1) Tighten the screws securely. Remove paper tag from plastic contact cover. Proceed to Step #5.

Factory-Installed Jumper

 

RH

W

B

O

Y

G RC A

Hot

 

Heat

 

 

Compressor

Fan

 

Relay

 

 

Relay

Relay

120 VAC

24 VAC

 

 

 

 

 

Neutral

TRANSFORMER

Figure 2. Typical wiring for single transformer heating/cooling system

 

RH

W

B

A

O

Y

G RC

 

TRANSFORMER

Heat

 

 

 

Compressor

Fan

TRANSFORMER

Hot

 

 

 

 

Hot

 

Relay

 

 

 

Relay

Relay

120 VAC

24 VAC

 

 

 

 

 

24 VAC

120 VAC

Neutral

 

 

 

 

 

 

 

Neutral

Figure 3. Typical wiring for two-transformer heating/cooling system

Factory-Installed JumperField-Installed Jumper

 

RC

G

RH

O

W

Y

B

A

TRANSFORMER

Fan

 

 

 

Compressor

 

 

Hot

 

 

*

 

* *

 

 

Relay

 

 

Relay

 

120 VAC

24 VAC

 

 

 

 

 

 

 

Neutral

 

 

 

 

 

 

 

 

 

Terminal energized

* *

Terminal energized

 

 

 

* in cooling

 

in heating

 

 

 

Figure 4. Typical wiring for single transformer, single stage heat pump system

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White Rodgers 1C26 installation instructions Mounting and Wiring, 1C20 Heat Only Two Wire