Aprilaire 8334 user manual Features, Replacing Existing Thermostat

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ELECTRONIC THERMOSTATS

MODEL 8334

1 Heat / 1 Cool Digital

Electric / Gas

User’s Manual

Installation and

Operation

IMPORTANT SAFETY INFORMATION

WARNING:

•Always turn off power at the main power source by unscrewing fuse or switching circuit breaker to the off position before installing, removing, cleaning, or servicing thermostat.

•Read all of the information in this manual before installing or programming this thermostat.

•This is a 24V AC low-voltage thermostat. Do not install on voltages higher than 30V AC.

•All wiring must conform to local and national building and electrical codes and ordinances.

•Do not short (jumper) across terminals on the gas valve or at the system control to test installation. This will damage the thermostat and void the warranty.

Features

•Single Stage heat pump compatible.

•Zone system compatible as a master thermostat.

•Low battery indicator.

•Fahrenheit/Celsius display option.

•Adjustable from 45(F (4°C) to 90°F (32(C).

•Accuracy within ± 1 degree.

•Adjustable temperature differential: .5 – 1.5 degree.

•Low temperature freeze protection. While in heat mode, thermostat will mechanically turn on heat if temperature drops to 40°F (4°C) – even if batteries are missing or drained.

•Automatic heating shutdown if temperature exceeds 90°F (32°C).

Replacing Existing Thermostat

1.Turn off power to heating and cooling system.

2.Remove cover of old thermostat to expose wires. Do not disconnect wires. (Fig. 1)

3.Label wires per Table 1.

Table 1

Old Label	New Label	Description
M, 4, RH, R5 or R	RH	Heat Transformer,
		hot side
V or RC	RC	Cooling Transformer,
		hot side
Y or Y6	Y	Cooling control
H, W or 4	W	Heating control
F or G	G	Fan control relay
C*	Y or None	Either cooling control
		or common side
		of transformer
O	O	Cool Active Reversing
		Valve
B	B	Heat Active Reversing
		Valve

*NOTE: On some older models, the C terminal can be either the cooling control or the common side of the transformer. Check furnace wiring diagram to verify C terminal. If it is the common side of the transformer,

cap the wire and tuck into the wall. If it is the cooling control, connect to the Y terminal.

Figure 1

4.After labeling wires, remove wires from terminals.

5.Remove existing thermostat base from wall.

6.Refer to the following section for instructions on how to install thermostat.

Installing Model 8334 Thermostat

NOTE: For new installations, mount thermostat on inside wall, 4-5 feet above the floor. Do not install behind a door, in a corner, near air vents, in direct sunlight, or near any heat or steam generating fixtures. Installation at these places will affect thermostat operation.

1.Turn power off to the heating and cooling systems.

2.Place COOL-OFF-HEAT

In OFF position.

COOL OFF HEAT

> > COOL OFF HEAT FAN: AUTO - ON

3. Place FAN: AUTO-ON switch	FAN: AUTO - ON
Into AUTO position.

4.Remove the cover using a coin or screwdriver.

Figure 2

5.Place thermostat against the wall at desired location. Make sure wires will feed through opening on base of thermostat.

6.Mark placement of mounting holes. See Fig. 3. Set base aside.

MOUNTING HOLES

7.Drill the marked holes using a 3/16" drill bit. NOTE: Enclosed plastic anchors do not require drilled hole for drywall.

8.Tap plastic anchors into the wall.

9.Align base with plastic anchors and feed wires through opening.

10.Secure base to wall with supplied screws.

11.Connect wires to terminal strip. Refer to wiring diagrams on other side of this sheet. Make sure wire connections are secure.

12.Place fan option switch into either the "ELEC" or "GAS" position depending upon the type of furnace. Refer to Figure 4.

ELECTRIC/

GAS SWITCH

figure 4

13.Put the °F/°C switch to either °F for Fahrenheit display or °C for Celsius display readout.

°F/°C F°/°C SWITCH Switch

14.Put the HP/NON HP switch to either the HP for Heat Pump or NON HP for furnace applications in the proper position.

HP/NON HP

Switch

15.Install two “AA” ENERGIZER brand batteries or equivalent into bat- tery compartment. Be sure to match positive (+) ends of batteries with positive (+) battery terminals in the battery compartment.

16.Replace cover onto thermostat by snapping into place.

17.Turn on power to system. Test thermostat as described in the following section.

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