Honeywell T8524C User Manual

Page 1

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

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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.

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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.

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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.

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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.

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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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T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

Table 2. Thermostat Installer Setup Options.

Installer Setup

Select

Number

(Press i key

to change)

Factory-Setting

Display Description Display Description Setting

Not used 01 — — — — — Fan operationa02 00 Conventional applica-

tions where equipment controls fan operation in heat mode

01 Heat pump and electric heat

Not used 03 and 04 — — — — — Stage-two

heating cycle rate

05 06 6 cph used for

conventional systems

01, 03, or 09

Not used 06 thru 11 — — — — — Changeover

(T8524D only)

12 01 Manual changeover 00 Automatic changeover

Not used 13 — — — — — Degree

temperature display

14 00 Temperature is

displayed in °F

01 Temperature is displayed in

Not used 15 thru 18 — — — — — Extended fan

operation in heating

Extended fan operation in cooling

19 00 No extended fan

a,b

20 00 No extended fan

operation after the call for heat ends

operation after the call for cool ends

01 Fan operation is extended

Not used 21 thru 23 — — — — — Outdoor

temperature display

24 00 No outdoor temperature

is displayed

01 Outdoor temperature is

Not used 25 thru 29 — — — — — Deadband 30 03 Heating and cooling

setpoints can be set no closer than 3°F (1.5°C)

04 thru10Heating and cooling

Not used 31 and 32 — — — — — Minimum off

time for the compressor

Available on select models.

Installer Setup Number 02 must be set to 01 to extend fan operation.

33 05 5 minute minimum off

time for the compressor

00, 01, 02, 03 or 04

Other Choices

(Press ▲ or ▼ key to change)

applications where thermostat controls fan operation in heat mode

01—1 cph used for radiant

floor heat, gravity systems

03—3 cph used for hot water

systems or high efficiency furnaces

09—9 cph used for electric

heat systems

°C

90 seconds after the call for heat ends

90 seconds after the call for cool ends

displayed. Needs a C7089B1000 Outdoor Sensor to operate.

setpoints can be set no closer than the chosen value:

04—4°F (2°C) 05—5°F (2.5°C) 06—6°F (3°C) 07—7°F (3.5°C) 08—8°F (4°C) 09—9°F (4.5°C) 10—10°F (5°C)

Minimum number of minutes (0 thru 5) the compressor will be off between calls for the compressor

Actual

(Continued)

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T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

Table 2. Thermostat Installer Setup Options (continued).

Installer Setup

Select

Heating setpoint range

stop Cooling

setpoint range

stop

Number

(Press i key

to change)

34 90 Heating setpoint can be

35 45

Factory-Setting

Display Description Display Description Setting

set no higher than 90°F

Cooling setpoint can be set no lower than 45°F

40 thru90Number can be set

45b thru99Number can be set

Not used 36 — — — — — Temperature

display adjustment

Available on select models.

T8524D is 48°F (9°C).

IMPORTANT

37 00 No difference in

Review the settings to confirm that they match the system.

displayed temperature and actual room temperature

-3 thru 3

Other Choices

(Press ▲ or ▼ key to change)

anywhere between 40 and 90 in 1°F increments

anywhere between 45 99 in 1°F increments

1—Display adjusts to 1°F

higher than actual room temperature

2—Display adjusts to 2°F

higher than actual room temperature

3—Display adjusts to 3°F

higher than actual room temperature

-1—Display adjusts to 1°F lower than actual room temperature

-2—Display adjusts to 2°F lower than actual room temperature

-3—Display adjusts to 3°F lower than actual room temperature

and

Actual

INSTALLER SYSTEM TEST

Use the Installer System Test to check the thermostat configurations and operation. Refer to Table 3 for a list of the available system tests.

To start the system test::

NOTE: The minimum off time for compressors is

bypassed during the Installer System Test.

Press and hold the increase ▲ and decrease ▼ keys, at the same time, until two zeros appear. All segments of the LCD are displayed before the two zeros appear.

Em Ht Temporary Setting Aux Ht

Repl

Wait

Batt

System Fan

Em HeatOffCool Auto Only

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Heat Cool

Remote

Room

%Humid

Outdoor

OnAuto

M4844

TEST MODE NUMBER

IMPORTANT

T8524C models must set the switches to the equipment that is being checked for the equipment to operate.

NOTE: Press and hold the increase ▲ and decrease ▼

keys for three seconds to exit the System Test. The System Test times out after five minutes without any key presses.

M6792

Table 3. Tests Available In The Installer System Test.

Test

Number System Test Description

10-19 Heating equipment can be turned on and off 30-39 Cooling equipment can be turned on and off 40-49 Fan equipment (T8524D only) can be turned

on and off. 60-69 System key or system switch position test 70-79 Thermostat information including date code

and software versions are displayed

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T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

Table 4. Installer System Test Options.

Key to

Press

Heating Equipment System test

▲ 11 Stage-one heat comes on. The system fan is also energized. ▲ 12 Stage-two heat comes on. Stage-one heat and system fan remain on. ▼ 11 Stage-two heat turns off. ▼ 10 Stage-one heat and system fan turn off.

Cooling Equipment System test

▲ 31 Stage-one cool and system fan come on. ▲ 32 Stage-two cool comes on. Stage-one cool and system fan remain on. ▼ 31 Stage-two cool turns off. ▼ 30 Stage-one cool and system fan turn off.

Fan Equipment System test (T8524D only)

▲ 41 Fan comes on. ▼ 40 Fan turns off.

Key or Switch Operation System test IMPORTANT

SYSTEM KEY OR SWITCH SYSTEM TEST (Move switch to see Test Numbers on T8524C.)

System 61 Heat Test Number is displayed. (Set system switch to HEAT on T8524C.) System 62 Off Test Number is displayed. (Set system switch to OFF on T8524C.) System 63 Cool Test Number is displayed. (Set system switch to COOL on T8524C.) System 64 Auto Test Number is displayed.

FAN KEY SYSTEM TEST (T8524D only)

Fan 68 Fan on Test Number is displayed. Fan 69 Fan off Test Number is displayed.

System fan is energized only if set for electric heat.

Thermostat Information

1. Press the Information i key to access the

Test

Number Description

thermostat information.

10 Enter heating equipment system test. (Set system switch to HEAT on T8524C.)

30 Enter cooling equipment system test. (Set system switch to COOL on T8524C.)

40 Change from cooling to fan equipment system test.

Test Numbers will only be displayed when the system is configured for the selected function. EXAMPLE: Numbers 60, 61 and 62 are the only numbers that will be displayed when a system is configured for heat only.

60 Change from cooling or fan to key operation system test.

2. Press the increase ▲ key to display the production

date code. The first two large digits are the month and the third digit is the last digit of the year. (Example: 026 = February 1996)

M4864

M4865

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T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

3. Press the increase ▲ key again to display the

software identification code. (Example: 02 = software ID code 2)

M4866

4. Press the increase ▲ key again to display the

software revision number. (Example: 001 = revision number 1)

5. Press the increase ▲ key again to display the

EEPROM identification code. (Example: 222 = EEPROM ID 222)

6. Press and hold the increase ▲ and decrease ▼

keys together, until the room temperature is displayed, to exit the System Test. The System Test times out after five minutes without any key presses.

CHECKOUT

Outdoor Temperature Sensor (Where Applicable)

Allow the outdoor temperature sensor to soak in the

M6791

outdoor air for a minimum of five minutes before taking a reading. With an accurate thermometer (±1°F [±0.5°C]), measure the temperature at the sensor location, allowing time for the thermometer to stabilize before reading. Match the thermometer reading to the outdoor temperature display at the thermostat.

TROUBLESHOOTING GUIDE

Symptom Possible Cause Action

Display will not come on.

Temperature display is incorrect.

Temperature settings will not change. (Example: Cannot set the

heating higher or the cooling lower.)

Available on select models.

Thermostat is not being powered.

Room temperature display has been reconfigured.

Thermostat is configured for °F or °C display.

Bad thermostat location. Relocate the thermostat. The upper or lower temperature

limits were reached.

The setpoint temperature range stops were configured.

• Check that C terminal is connected to the system transformer.

• Check for 24 Vac between C and R or RH terminals. — If missing 24 Vac:

— check if the circuit breaker is tripped—reset the

circuit breaker. — check if the system fuse is blown—replace the fuse. — check if the power switch on the HVAC equipment is

in the Off position—set to the On position. — check wiring between thermostat and HVAC

equipment—replace any broken wires and tighten

any loose connections.

— If 24 Vac is present, proceed with troubleshooting.

Enter Installer Setup Number 37 and reconfigure the display.

Enter Installer Setup Number 14 and reconfigure the display.

Check the temperature setpoints:

• Heating limits are 40 to 90°F (7 to 31°C)

• Cooling limits are 45 to 99°F (9 to 37°C) except T8524D cooling limits are 48 to 99°F

Check Installer Setup mode numbers 34 and 35 and reconfigure the setpoint stops.

M4867

(Continued)

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T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

TROUBLESHOOTING GUIDE (Continued)

Symptom Possible Cause Action

Heating will not come on.

Cooling will not come on.

Heating or cooling comes on momentarily and shuts off

System On indicator is lit, but no heat is being delivered.

Outdoor temperature not displayed

Outdoor temperature display is incorrect

Available on select models.

No power to the thermostat. • Check that C terminal is connected to the system

Thermostat minimum off time is activated.

System selection is not set to Heat.

Heating setpoint is below room temperature.

No power to the thermostat. • Check that C terminal is connected to the system

Thermostat minimum off time is activated.

System selection is not set to Cool.

Cooling setpoint is above room temperature.

Heat or cool circuit is opening up or becoming high impedance.

Fan operation set for 00 (conventional heat) when it should be set for 01 (electric heat).

Conventional heating equipment turns on the fan when the furnace has warmed up to a setpoint.

Heating equipment is not operating.

Option not activated. Enter Installer Setup mode number 24 and set to 01.

Outdoor sensor is connected incorrectly.

Wrong sensor. Replace sensor with C7089B1000 sensor.

transformer.

• Check for 24 Vac between C and R or RH terminals. — If missing 24 Vac:

— check if the circuit breaker is tripped—reset the

circuit breaker. — check if the system fuse is blown—replace the fuse. — check if the system switch at the equipment is in the

Off position—set to On position. — check wiring between thermostat and HVAC

equipment—replace any broken wires and tighten

any loose connections.

— If 24 Vac is present, proceed with troubleshooting.

Wait up to five minutes for the system to respond.

Set system selection to Heat.

Check heating setpoint. Set heating setpoint to desired temperature.

transformer.

• Check for 24 Vac between C and R or RC and Y terminals. — If missing 24 Vac:

— check if the circuit breaker is tripped—reset the

circuit breaker. — check if the system fuse is blown—replace the fuse. — check if the system switch at the equipment is in the

Off position—set to the On position. — check wiring between thermostat and HVAC

equipment—replace any broken wires and tighten

any loose connections.

— If 24 Vac is present, proceed with troubleshooting.

•Wait up to five minutes for the system to respond.

• Enter Installer Setup mode number 33. Reconfigure minimum off time (if required).

Set system selection to Cool.

Check cooling setpoint. Set cooling setpoint to desired temperature.

Add resistor in parallel with load or install interface relay.

Enter Installer Setup mode number 02 and reconfigure the fan operation.

Wait a minute after seeing the On indicator and then check the registers.

Verify operation of heating equipment in system test.

Thermostat must have OT terminals and a C7089B1000 installed.

Refer to C7089B1000 installation instructions and check wiring between the thermostat and sensor.

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T8524C,D MULTISTAGE MICROELECTRONIC THERMOSTATS

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Home and Building Control

Honeywell Inc. Honeywell Plaza P.O. Box 524 Minneapolis, MN 55408-0524

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69-1055—1 J.H. Rev. 6-97 www.honeywell.com/yourhome

Home and Building Control

Honeywell Limited-Honeywell Limitée 155 Gordon Baker Road North York, Ontario M2H 3N7