Honeywell T8501 Installation instructions

T8501

Microelectronic Thermostats

INSTALLATION INSTRUCTIONS

APPLICATION

The T8501 Microelectronic Thermostats provides electronic control of 24 Vac single-stage heating and cooling systems. Refer to Table 1 for a general description of the thermostat. All T8501 thermostats require a common wire to supply power.

System

Heat-Cool

Changeover

Automatic

MERCURY NOTICE

If this control is replacing a control that contains mercury in a sealed tube, do not place your old control in the trash. Dispose of properly.

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

INSTALLATION

Table 1. Description of T8501 Thermostats.

System Selection

Heat-Off-Cool-Auto

Fan

Selection

On-Auto

Comments

System and fan selections are done by keyboard.

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.

Location

Install the thermostat about 1.5m (5 ft) 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. (50.8 mm x 101.6 mm) wiring box.

Position wallplate horizontally on the wall or on a

2 in. x 4 in. (50.8 mm x 101.6 mm) wiring box.

1. Position and level the wallplate (for appearance only). The thermostat will function properly even when not level.

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 (76 mm) holes in the wall (if drywall) as marked. For firmer material such as plaster, drill two 7/32 inch (5.56 mm) holes. Gently tap anchors

(provided) into the drilled holes until flush with the 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.

® U.S. Registered Trademark

Copyright © 2004 Honeywell • • All Rights Reserved

69-0925-4

T8501 MICROELECTRONIC THERMOSTATS

NO

YES

NO

NO

5 FEET

[1.5 METERS]

M10106

WALL

ANCHORS

(2)

WIRES

THROUGH WALL

Fig. 1. Typical location of thermostat.

WALL

MOUNTING

HOLES

CAUTION

Electrical Shock Hazard.

Can cause electrical shock and equipment damage.

Disconnect power before wiring.

1. Loosen the terminal screws on the wallplate and connect the system wires. See Fig. 6.

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.

THERMOSTAT

C W R

MOUNTING

SCREWS

O T

2

O T

OUTDOOR

TEMPERATURE

SENSOR

HEATING

RELAY OR

VALVE COIL

M6530A

Fig. 2. Mounting the wallplate.

WIRING

All wiring must comply with local electrical codes and ordinances. Refer to Fig. 3 and 5 for typical hookup. A letter code is located near each terminal for identification.

1

L1

(HOT)

L2

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND

OVERLOAD PROTECTION AS REQUIRED.

2 AVAILABLE ON SELECT MODELS.

M4822

Fig. 3. Typical hookup in heat only application.

69-0925—4 2

O T

2

O T C B

THERMOSTAT

O G Y W R

OUTDOOR

TEMPERATURE

SENSOR

HEATING

RELAY OR

VALVE COIL

COMPRESSOR

CONTACTOR

HEAT

CHANGEOVER

VALVE OR

DAMPER

COOL

CHANGEOVER

VALVE OR

DAMPER

FAN

RELAY

1

L1

(HOT)

L2




M4821

Fig. 4. Typical hookup in heat and cool system with one transformer.


.

FOR WRAPAROUND

INSERTION STRIP

7/16 IN. (11 MM).

FOR STRAIGHT INSERTION

STRIP 5/16 IN. (8 MM).

M4826

Fig. 6. Correct wiring technique.

Mounting Thermostat

1. Engage tabs at the top of the thermostat and wallplate. See Fig. 7.

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

NOTE: To remove the thermostat from the wall, first pull out at the bottom of the thermostat; remove top last.

A.

ENGAGE TABS AT TOP OF THERMOSTAT AND WALLPLATE.

O T

2

O T Rc O

THERMOSTAT

G Y C B W

3

Rh

OUTDOOR

TEMPERATURE

SENSOR

FAN

RELAY

COMPRESSOR

CONTACTOR

COOL

CHANGEOVER

VALVE OR

DAMPER

L1

(HOT)

L2

1

HEAT

CHANGEOVER

VALVE OR

DAMPER

HEATING

RELAY OR

VALVE COIL

1

L1

(HOT)

L2




3 JUMPER Rh TO Rc IN A SINGLE TRANSFORMER SYSTEM.

M4820

Fig. 5. Typical hookup in heat and cool system with two transformers.

B.

PRESS LOWER EDGE OF CASE TO LATCH.

M6798A

Fig. 7. Mounting thermostat on wallplate.

3 69-0925—4


Using Thermostat Keys

The thermostat keys are used to:

• set the temperature,

• display present setting,

• configure Installer Setup,

• check System-Test,

• display outdoor temperature (select models), i

System

System

Press to select heating or cooling equipment.

Em. Ht.-Emergency heating

HeatÑ Heating equipment

Off Ñ No equipment

CoolÑCooling equipment

AutoÑ Thermostat selects

heating

equipment.

Fan

Press to select heating or cooling equipment.

AutoÑ Fan runs when

heating

System

1

Fan

Fan Select models have keys to:

• set the system operation,

• set the fan operation.

NOTE: Always press the keys with your fingertip or similar blunt tool. Sharp instruments like a pen or pencil point can damage the keyboard.

See Fig. 8 for key locations.

i

INCREASE

TEMPERATURE

SETTING

DECREASE

TEMPERATURE

SETTING

DISPLAY PRESENT

SETTINGS AND SCROLL

THROUGH INSTALLER

SETUP (INFORMATION KEY)

M6801A

Fig. 8. Thermostat key locations and descriptions.

SETTINGS

System and Fan Settings

System settings control the thermostat operation:

Heat: The thermostat controls the heating.

Off: Both the heating and cooling are off.

Cool: The thermostat controls the cooling.

Auto: The thermostat automatically changes between heating and cooling operation, depending on the indoor temperature.

Fan settings control the system fan:

On: Fan operates continuously.

Auto: Fan operates with equipment.

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 Fig. 9.

1 LED INDICATOR.

M10147C

Fig. 9. T8501 System and Fan key locations.

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.

INSTALLER SETUP

NOTE: For most applications, the thermostat factorysettings do not need to be changed. Review the factory settings in Table 2 and if no changes are necessary, go to the Installer Self-Test section.

The Installer Setup is used to customize the thermostat to specific systems. Some of the options include:

— temperature display,

— changeover and

— outdoor temperature display.

Installer Setup numbers are listed in Table 3. The table includes all the configuration options and the factorysettings for the T8501.

A combination of key presses are required to use the

Installer Setup feature:

— To enter the Installer Setup, 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. 11 and 12.

— To advance to the next Installer Setup, press the

i key.

— To change a setting, use the increase ! or decrease # 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 backward to get to the normal display. The

Installer Setup is automatically exited if no key presses are made for five minutes.

NOTE: Only configurable number are shown.

69-0925—4 4

.

Em Ht Temporary Setting

Aux Ht

Repl

Batt Wait

System

Heat Cool

Em HeatOffCool Auto Only

Remote

Room

%Humid

Outdoor

Fan

OnAuto

M4844

Fig. 10. Display of all LCD segments.

INSTALLER SETUP

NUMBER DISPLAY

(COLUMN 1 OF TABLE 2)

FACTORY SETTING OR

OTHER CHOICE DISPLAY

(COLUMN 3 OR 5 OF TABLE 2)


CAUTION

Equipment Damage Hazard.

Heat pump and electric heat systems can be damaged when run without fan.

Configure to 01 in Installer Setup number 02 to prevent equipment damage.

IMPORTANT

Only configurable numbers are shown on the device. Example: If thermostat does not have a system key, Installer Setup Number 12 does not display. Review Table 3 factory-settings and mark any desired changes in the Actual Setting column. When Installer Setup is complete, review the settings to confirm that they match the system.

M10105B

Fig. 11. Display of Installer Setup number and setting.

Select

Not Used.

Fan operation

Not Used.

a

Not Used.

Heating cycle rate.

Changeover

(T8501D only)

Not used

Installer Setup

Number (Press i key to change)

01

02

03

04

05 thru 11

12

Table 2. Thermostat Installer Setup Options.

Display

—

0

—

6

—

01

Factory Setting

Description

—

Conventional applications where equipment controls fan operation in heat mode.

—

6 cph used for conventional systems

—

Manual changeover

Other Choices

(Press ! or # key to change)

Display

—

01

Description

—

Heat pump or electric heat applications where thermostat controls fan operation in heat mode.

—

01, 03 or 09

—

00

—

01—1 cph used for radiant floor heat, gravity system

03—3 cph used for hot water systems or high efficiency furnaces

09—9 cph used for electric heat systems

—

00—Auto changeover

13 — — — —

5 69-0925—4


Select

Degree temperature display

Not Used.

Extended fan operation in heating.

a,b

Extended fan operation in cooling.

a

Not Used.

Outdoor temperature display a

Not Used.

Minimum off time for the compressor.

Temperature range stops in heating.

Temperature range stops in cooling.

System On display.

Temperature display a adjustment.

Table 2. Thermostat Installer Setup Options. (Continued)

Installer Setup

Number (Press i key to change)

14

Display

00

Factory Setting

Description

Temperature is displayed in °F

Other Choices

(Press ! or # key to change)

Display

01

Description

Temperature is displayed in °C

15 thru 18

19

20

21 thru 23

24

25 thru 32

33

34

35

36

37

—

00

00

—

00

—

05

90

45

00

00 c

—

No extended fan operation after the call for heat ends.

No extended fan operation after the call for cool ends.

—

No outdoor temperature is displayed.

—

5 minutes minimum off time for the compressor.

Heating setpoint can be set no higher than 90°F.

Lowest setpoint cooling can be set to.

LCD On symbol is displayed when system is energized.

No difference in displayed temperature and actual room temperature.

—

01

01

Fan operation is extended 90 seconds after the call for heat ends.

Fan operation is extended 90 seconds after the call for cool ends.

—

—

01

—

00, 01,

02, 03 or 04

—

Outdoor temperature is displayed. Needs a C7089B1000

Outdoor Temperature Sensor to operate.

—

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

40 to 90 Number can be set anywhere between 40 and 90 in 1°F increments.

45 to 99 Number can be set anywhere between 45 and 99 in 1°F increments.

01 Display is disabled, usually set for 01 for a zoned system.

+3 thru

03

01—Display adjusts to 1°F higher than actual room temperature.



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



a Available on select models.

b Mode 02 must be set to 01 to extend fan operation.

IMPORTANT

Review the settings to confirm that they match the system. Press Run Program to exit the

Installer Setup. The thermostat has saved the

69-0925—4 6

Installer Setup changes and initiated a reset in order to operate using the new settings. Be sure to set the current day and time immediately.


INSTALLER SYSTEM TEST

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

CAUTION

Equipment Damage Hazard.

Minimum off time for compressor is bypassed during Installer System Test.

Prevent compressor from cycling too quickly.

To start the system test:

Press and hold the increase ! and decrease # keys at the same time until two zeros (00) appear. All segments of the LCD are displayed before 00 appears.

See Fig. 11 and 12.

Em Ht Temporary Setting

Aux Ht

Repl

Batt Wait

System

Heat Cool

Em HeatOffCool Auto Only

Remote

Room

%Humid

Outdoor

Fan

OnAuto

M4844

Fig. 12. Display of all LCD segments.

Table 3. Tests Available In Installer System Test.

Test

Number

10-19

30-39

40-49

60 0 to

60 19

70-79 off.

System Test Description

Heating equipment can be turned on and

Cooling equipment can be turned on and off.

Fan equipment can be turned on and off.

Keyboard keys test.

Thermostat information including date code and software versions are displayed.

TEST NUMBER M6792A

Fig. 13. Display of test number.

Refer to Table 4 for the directions and results of the specific tests.

IMPORTANT

Models with System and Fan switches 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 mode. The system test times out after five minutes without any key presses.

Table 4. Installer System-Test Options.

Keys to

Press

Test

Number Description

Heating Equipment System-Test i 10 Enter heating equipment system-test. (Set System switch to Heat on switch models.)

!

11 Heat comes on. When Installer Setup number 02 is 01, the system fan is also energized.

# 10 Heat and system fan turn off.

Cooling Equipment System Test i 30

!

31

Change from heating to cooling equipment system test. (Set system switch to Cool on switch models.)

Cool and system fan come on.

# 30 Cool and system fan turn off.

Fan Equipment System Test (T8501D only) i 40 Change from cooling to fan equipment system-test.

!

#

41

40

Fan comes on.

Fan turns off.

7 69-0925—4


Table 4. Installer System-Test Options. (Continued)

Keys to

Press

Test

Number Description

Key or Switch Operation System-Test a

IMPORTANT

Test numbers are displayed only when the system is configured for the selected function.

Example: Numbers 60, 61 and 62 are the only numbers that are displayed when a system is configured for heat only.

System Key or Switch System Test (When System switch is used, move switch to see Test Numbers.) i 60 Change from cooling or fan to key operation system test.

System

System

System

61

62

63

Heat test number is displayed. (Set System switch to Heat.)

Off test number is displayed. (Set System switch to Off)

Cool test number is displayed. (Set System switch to Cool.)

System 64 Auto Test number is displayed.

Fan Key System Test (Fan switch cannot be tested)

Fan

Fan

68

69 a Available on select models.

69-0925—4 8

THERMOSTAT INFORMATION

1. Press the i key to access the thermostat information.


4. Press the increase ! key again to display the software revision number (Example: 001 = revision number 1).

M4864

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).

M6791

5. Press the increase ! key again to display the

EEPROM identification code. (Example: 222 =

EEPROM ID 222.)

M4865

3. Press the increase ! key again to display the software identification code. (Example: 02 = software

ID code 2).

M4866

M4867

6. Press and hold the increase ! and decrease # keys together, until the room temperature is displayed, to exit the system test mode. The system test times out after five minutes without any key presses.

CHECKOUT

Outdoor Temperature Sensor

(Select Models)

Allow the outdoor temperature sensor to take in the 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.

9 69-0925—4


TROUBLESHOOTING GUIDE

Symptom

Display will not come on.

Temperature display is incorrect.

Temperature settings will not change. (Example:

Cannot set the heating higher or the cooling lower.)

Heating will not come on.

Table 5. Troubleshooting Guide.

Possible Cause

Thermostat is not being powered.l

Action

• 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.

Remove the thermostat from the wallplate for two minutes. After two minutes, replace the thermostat on the wallplate.

Enter Installer Setup number 37 and reconfigure the display.

Thermostat microprocessor is locked up.

Room temperature display has been reconfigured.

Thermostat is configured for °F or °C display.

Enter Installer Setup number 14 and reconfigure the display.

Bad thermostat location.

The upper or lower temperature limits were reached.

Relocate the thermostat.

Check the temperature setpoints:

• Heating limits are 40 to 90°F (4.5 to 32°C)

• Cooling limits are 45 to 99°F (7 to 37°C).

The setpoint temperature range stops were configured.

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

No power to the thermostat.


• Check for 24 Vac between C and R or RH terminals.




— check if the System switch on the HVAC equipment is in the Off position—set to the On position.



Wait up to five minutes for the system to respond.

Thermostat minimum off time is activated.

System selection is not set to

Heat.

Set system selection to Heat.

69-0925—4 10


Table 5. Troubleshooting Guide. (Continued)

Symptom

Cooling will not come on.

Possible Cause

No power to the thermostat.

Thermostat minimum off time is activated.

Action


• Check for 24 Vac between C and R or RC and Y terminals.




— check if the power switch on the HVAC equipment is in the Off position—set to the On position.



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

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

Set system selection to Cool.

System on indicator is displayed, but no heat is being delivered.

System selection is not set to

Cool.

Fan operation set for 00

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

Outdoor temperature not displayed a

Outdoor temperature display is incorrect a

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

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

Heating equipment is not operating.

Option not activated.

Verify operation of heating equipment in self-test.

Enter Installer Setup number 24 and set to 01. Thermostat must have OT terminals and a C7089B1000 installed.

Outdoor sensor is connected incorrectly.

Wrong sensor.

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

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

Replace sensor with C7089B1000 sensor.

a Select Models

11 69-0925—4


Automation and Control Solutions

Honeywell

1985 Douglas Drive North

Golden Valley, MN 55422

Honeywell Limited-Honeywell Limitée

35 Dynamic Drive

Scarborough, Ontario

M1V 4Z9

69-0925—4 G.H. Rev. 04-04 www.honeywell.com/yourhome

Honeywell T8501 Installation instructions

T8501

Microelectronic Thermostats

INSTALLATION INSTRUCTIONS

APPLICATION

MERCURY NOTICE

INSTALLATION

When Installing this Product...

Location

Wallplate Installation

CAUTION

WIRING

Mounting Thermostat

Using Thermostat Keys

SETTINGS

System and Fan Settings

Temperature Settings

INSTALLER SETUP

Em Ht Temporary Setting

Aux Ht

Repl

Batt Wait

System

Heat Cool

Em HeatOffCool Auto Only

Remote

Room

%Humid

Outdoor

Fan

OnAuto

CAUTION

INSTALLER SYSTEM TEST

CAUTION

Em Ht Temporary Setting

Aux Ht

Repl

Batt Wait

System

Heat Cool

Em HeatOffCool Auto Only

Remote

Room

%Humid

Outdoor

Fan

OnAuto

THERMOSTAT INFORMATION

CHECKOUT

Outdoor Temperature Sensor

(Select Models)

TROUBLESHOOTING GUIDE

Key Features

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Frequently Answers and Questions

What is the Honeywell T8501?