Aprilaire 8246 Installation And Operation Manual

Thermostat

Model 8246 Installation and Operation Manual

Non-Programmable Heat Pump Thermostat

Failure to follow and read all instructions carefully before installing or operating this control could cause personal
injury and/or property damage. If you have any questions, please call Research Products Corporation at [phone].

PREPARATIONS

Assemble tools required as shown below.

Wire cutter/stripper

Flat blade

screwdriver

Electric or cordless
drill with 3/16 inch

drill bit, if needed.

THERMOSTAT DETAILS

FIGURE 1 – Thermostat Base

Mounting

hole

Mounting hole

O/B

Terminal

Selection

Switch

Level

W904 Clip

for Celsius

instead of

Fahrenheit

W905 Clip for

Slow Cycle

instead of
Fast Cycle

W906 for Emergency Heat

Second Stage Fan Control.

Clip for Fan Control by Equipment

instead of by Thermostat.

THERMOSTAT APPLICATIONS

Description

Heat Pump (No Aux or Emergency Heat) Yes

Heat Pump (with Aux or Emergency Heat) Yes

Standard Heat & Cooling Systems No

Standard Heat Only Systems No

Millivolt Heat Only Systems – Floor or Wall Furnaces No

MOUNTING AND WIRING

WARNING

120 volts may cause serious injury from electrical
shock. Disconnect electrical power to the furnace & air
conditioner before starting installation. This thermostat
is not a 120 volt (line voltage) device.

Improper installation may cause serious injury from electrical
shock. This product must be installed by a qualifi ed
heating & air conditioning contractor in accordance with
NEC Standards and applicable local and state codes.

Do not use on circuits exceeding specifi ed voltage.
Higher voltage will damage control and could cause
shock or fi re 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 NEC code.

ELECTRIC/GAS JUMPER (FAN OPTION)

If your emergency or auxiliary system will energize the blower, then
jumper W906 on the thermostat base must be cut (see Figure 1).

If your emergency or auxiliary heat system requires that the
thermostat energize the fan circuit, do not cut jumper W906.

If you are unsure of your application, contact a qualifi ed service
person.

°F OR °C SELECTION

The factory default setting for temperature display is Fahrenheit.
If you want the temperature in Celsius, clip jumper W904.

FAST OR SLOW CYCLE SELECTION

The factory default setting is fast cycle, which cycles 1st stage with
a temperature swing of approximately 1.2°F and 2nd stage with

0.75°F. If you prefer slow cycle, clip jumper W905. The 1st stage
and 2nd stage temperature swing will become 1.5°F and 1.2°F
respectively.

Description

Standard Central Air Conditioning No

Gas or Oil Heat No

Electric Furnace No

Hydronic (Hot Water) Zone Heat – 2 Wires No

Hydronic (Hot Water) Zone Heat – 3 Wires No

O/B TERMINAL SELECTION SWITCH

The O/B switch on this thermostat is factory set to the “B” position.
This will accommodate the majority of heat pump applications which
require the changeover relay to be energized in HEAT. If the heat
pump being installed with this thermostat requires an “O” terminal
to energize the changeover relay in COOL, the O/B switch must be
moved to the “O” position.

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.

BATTERY LOCATION

This thermostat does not require batteries to operate. The 2 “AAA”
alkaline batteries are for the thermostat to remember the confi guration
menu selections if AC voltage is lost. If the display shows BATT
when AC power is not present, the batteries are low and should be
replaced with fresh “AAA” Energizer® alkaline batteries. To replace the
batteries, install the batteries along the top of the base (see Figure 1).
The batteries must be installed with the positive (+) ends to the right.

CHOOSE A LOCATION TO MOUNT THE THERMOSTAT

MOUNT THE THERMOSTAT…

• Approximately 5 feet above the fl oor. Refer to local codes for
compliance with the Americans with Disabilities Act (ADA).

• On an interior wall in a frequently occupied space where the
temperature is most representative of the zone being controlled
by the thermostat.

• At least 18 inches away from an outside wall.

DO NOT MOUNT THE THERMOSTAT…

• Behind doors, in corners or other dead air spaces.

• In direct sunlight, near lamps or other sources of heat.

• On an outside wall or any wall exposed to an unconditioned space
(a garage for example).

• In the airfl ow path of a supply register, in stairways or near
outside doors.

• On a wall where concealed pipes or ductwork will affect the
thermostat temperature accuracy.

• Near sources of electrical interference, such as arcing switch contacts.

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