White Rodgers 350 Mounting And Wiring, Removing Old Thermostat, Continued From First Page

3 REMOVING OLD THERMOSTAT

CONTINUED FROM FIRST PAGE

ATTENTION! This product contains mercury. There will not be any exposure to mercury under normal conditions of use. 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 disgarded.

Mercury must not be discarded in household trash. When the unit this product is replacing is to be discarded, place in a suitable container and return to White-Rodgers at 9797 Reavis Road, St. Louis, MO, 63123-5398 for proper disposal.

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.

Model 350 (Heating and Cooling):

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

B.Mount switching subbase: Use the screws provided to mount the subbase 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. 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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