Honeywell T8524C User Manual

T8524C,D Multistage

Microelectronic Thermostats

INSTALLATION INSTRUCTIONS

APPLICATION

The T8524C, D Multistage Microelectronic Thermostat provides electronic control of 24 Vac two-stage heating and twostage cooling systems. Refer to Table 1 for a general description of the thermostat. All T8524 Thermostats require a common wire to supply power.

Table 1. Description of T8524 Thermostats.

T8524 System Changeover

C Heat-Cool Manual Heat-Off-Cool On-Auto System and fan selections are done by

D Heat-Cool Automatic Heat-Off-Cool-Auto On-Auto System and fan selections are done by

System

Selection

Fan

Selection Comments

switches.

keyboard.

RECYCLING NOTICE

If this control is replacing a control that contains mercury in a sealed tube, do control in the trash.

Contact your local waste management authority for instructions regarding recycling and the proper disposal of the old thermostat.

not

place your old

INSTALLATION

When Installing this Product...

1. Read these instructions carefully. Failure to follow

the instructions can damage the product or cause a hazardous condition.

2. Check the ratings given in the instructions and on

the product to make sure the product is suitable for your application.

3. Installer must be a trained, experienced service

technician.

4. After completing installation, use these instructions

to check out the product operation.

CAUTION

Disconnect power supply to prevent electrical shock or equipment damage.

Location

Install the thermostat about 5 ft (1.5m) above the floor in an area with good air circulation at average temperature. See Fig. 1.

Do not install the thermostat where it can be affected by: — drafts, or dead spots behind doors and in corners. — hot or cold air from ducts. — radiant heat from sun or appliances. — concealed pipes and chimneys. — unheated (uncooled) areas such as an outside wall

behind the thermostat.

Wallplate Installation

The thermostat can be mounted horizontally on the wall or on a 2 in. x 4 in. wiring box. Position wallplate horizontally on the wall or on a 2 in. x 4 in. wiring box.

1. Position and level the wallplate (for appearance

only). The thermostat will function properly even when not level.

X-XX UL

69-1055-1

T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

WALL ANCHORS (2)

WIRES THROUGH WALL

YES

5 FEET

[1.5 METERS]

Fig. 1. Typical location of thermostat.

WALL

4. Position the wallplate over the holes, pulling wires

through the wiring opening.

5. Loosely insert the mounting screws into the holes.

6. Tighten mounting screws.

WIRING

All wiring must comply with local electrical codes and ordinances. Refer to Fig. 3 for typical hookups. A letter code is located near each terminal for identification.

M10106

MOUNTING HOLES

MOUNTING SCREWS

Fig. 2. Mounting the wallplate.

2. Use a pencil to mark the mounting holes. See Fig. 2.

3. Remove the wallplate from the wall and drill two

3/16 inch holes in the wall (if drywall) as marked. For firmer material such as plaster or wood, drill two 7/32 inch holes. Gently tap anchors (provided) into the drilled holes until flush with the wall.

69-1055—1

M6530

CAUTION

Disconnect power before wiring to prevent electrical shock or equipment damage.

1. Loosen the terminal screws on the wallplate and

connect the system wires. See Fig. 4.

IMPORTANT

Use 18 gauge, color-coded thermostat cable for proper wiring.

2. Securely tighten each terminal screw.

3. Push excess wire back into the hole.

4. Plug the hole with nonflammable insulation to

prevent drafts from affecting the thermostat.

T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

THERMOSTAT

Y1 G C

COMPRESSOR CONTACTOR 1

L1 (HOT)

POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.

JUMPER RC TERMINAL TO R TERMINAL WHEN INSTALLED ON A ONE TRANSFORMER SYSTEM.

CAN BE USED FOR CHANGEOVER VALVE ON HEAT

PUMP SYSTEMS.

Fig. 3. Typical hookup of T8524 in a multistage

FAN

COMPRESSOR

RELAY

CONTACTOR 2

COOL DAMPER

COOLING TRANSFORMER

heating and cooling system.

FOR WRAPAROUND INSERTION STRIP 7/16 IN. (11 MM).

HEAT RELAY 2

HEAT DAMPER

FOR STRAIGHT INSERTION STRIP 5/16 IN. (8 MM).

HEAT RELAY 1

M4826

Fig. 4. Proper wiring technique.

Mounting Thermostat

1. Engage tabs at the top of the thermostat and

wallplate. See Fig. 5.

2. Press lower edge of case to close and latch.

Using Thermostat Keys

The thermostat keys are used to:

• set temperature,

• display present setting,

• configure Installer Setup,

• check System Test,

• display outdoor temperature (select models).

T8524D has keys to:

• set the system operation,

• set the fan operation.

See Fig. 6 for key information.

OT OTB

RW1

OUTDOOR SENSOR

L1 (HOT)

HEATING TRANSFORMER

M11309

ENGAGE TABS AT TOP OF THERMOSTAT AND WALLPLATE.

PRESS LOWER EDGE OF CASE TO LATCH.

M6798A

Fig. 5. Mounting thermostat on wallplate.

NOTE: To remove the thermostat from the wall, first pull out

at the bottom of the thermostat; remove top last.

INCREASE TEMPERATURE SETTING

DECREASE TEMPERATURE SETTING

DISPLAY PRESENT SETTINGS AND SCROLL THROUGH INSTALLER SETUP MODES (INFORMATION KEY)

M6801

Fig. 6. Thermostat key locations and descriptions.

SETTINGS

System and Fan Settings

System settings control the thermostat operation as follows:

Heat: The thermostat controls the heating. Off: Both the heating and cooling are off. Cool: The thermostat controls the cooling. Auto (T8524D only): The thermostat automatically

changes between heating and cooling operation, depending on the indoor temperature.

Fan settings control the system fan as follows:

On: Fan operates continuously. Auto: Equipment controls fan.

The system default setting is Heat and the fan default setting is Auto. Use the keyboard or system and fan switches, depending on model, to change to the desired settings. See Figs. 7 and 8.

69-1055-1

T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

A combination of key presses are required to use the Installer Setup feature.

HEAT OFF COOL

ON AUTO

M10146

SYSTEM

Selection for heating or cooling equipment operation.

Heat - Heating equipment Off - No equipment Cool - Cooling equipment

HEAT OFF COOL

ON AUTO

FAN

On - Fan runs continuously Auto - Fan runs when

heating or cooling equipment operates

Fig. 7. T8524C system and fan switches location.

Fan

System

Press to select

heating or cooling

equipment.

equipment. Em. Ht.

-Emergency heating

On— Fan runs continuously

Heat—Heating equipment

Auto—Fan runs when Off — No equipment Cool—Cooling equipment Auto—Thermostat

automatically selects heating and cooling equipment.

CHECK LIGHT ON SELECT MODELS

heating or cooling equipment operates

System

Fan

System

Fan

M10147

Fig. 8. T8524D system and fan keys location.

NOTE: Always press the system and fan keys with your

fingertip or similar blunt tool. Sharp instruments like a pen or pencil point can damage the keyboard.

Temperature Settings

The default setpoint for heat is 70°F (21°C) and for cool is 78°F (25.5°C). Press the increase ▲ or decrease ▼ key to change the present setting. To change between heat and cool, press the Information i key until the setting to be changed appears.

— To enter the Installer Setup mode, press and hold the

Information i key with the increase ▲ and decrease ▼ keys until the first number is displayed. All display segments appear for approximately three seconds before the number is displayed. See Fig. 9 and 10.

— To advance to the next Installer Setup number, press

the Information i key.

— To change a setting, use the increase ▲ or de-

crease ▼ key.

— To exit the Installer Setup, press and hold the

Information i key until the display returns to normal (approximately three seconds). The display scrolls the numbers backwards to get to the normal display. The Installer Setup is automatically exited if no key presses are made for five minutes.

IMPORTANT

Em Ht Temporary Setting Aux Ht

Repl Batt

Em HeatOffCool Auto Only

Fig. 9. Display of all the segments of the LCD.

Only configurable numbers are shown on the device. Example: If the thermostat does not have a system key, Installer Setup Number 12 will not be displayed. Review Table 2 factory-settings and mark any desired changes in the Actual Setting column. When Installer Setup in complete, review the settings to confirm that they match the system.

Remote

Room

%Humid

Wait

System Fan

Heat Cool

MODE NUMBER DISPLAY (COLUMN 2 OF TABLE 2)

Outdoor

OnAuto

M4844

FACTORY SETTING OR OTHER CHOICE DISPLAY (COLUMN 3 OR 5 OF TABLE 2)

INSTALLER SETUP

NOTE: For most applications, the thermostat factory-

settings do not need to be changed. Review the factory-settings in Table 2 and if no changes are necessary, go to the Installer System Test section.

The Installer Setup is used to customize the thermostat to specific systems. Installer Setup Numbers are listed in Table 2. The table includes all the configuration options available.

69-1055—1

Fig. 10. Display of Installer Setup mode and setting.

CAUTION

Electric heat systems must be configured to 01 in Installer Setup 02 to prevent equipment damage caused by the system running without the fan.

M10105

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