Honeywell T7351 User Manual

T7351 Commercial Programmable Thermostat

FOR SINGLE- OR MULTI-STAGE CONVENTIONAL/HEAT PUMP SYSTEMS

PRODUCT DATA

FEATURES

• Typically used in buildings (including: restaurants, shopping malls, office buildings and banks) under 55,000 square feet.

• For single zone rooftop units, split systems, heat pumps or hot/chilled water systems.

• 365-day programming.

• Two Occupied and two Not Occupied periods per day.

• Individual heat and cool setpoints available for Occupied and Not Occupied periods.

• P+I+D control minimizes temperature fluctuations.

• Recovery ramp control automatically optimizes equipment start times based on building load.

• Convenient overrides allow temporary setpoint

APPLICATION

The T7351 Commercial Programmable Thermostat controls 24 Vac commercial single zone heating, ventilating and air conditioning (HVAC) equipment. The T7351 consists of a thermostat and subbase. The thermostat includes the keypad and display for 365-day programming. The subbase includes equipment control connections. The subbase mounts on the wall and the thermostat mounts to the subbase.

changes.

• Keypad multi-level lockout available with all models.

• Remote sensor capability for temperature (including outdoor air and discharge air) and humidity sensors.

• Auxiliary subbase contact typically interface with a Honeywell Economizer System (for total rooftop control integration) or act as dehumidification output.

• Universal Versaguard Thermostat guards available.

Contents

Application ........................................................................ 1

Features ........................................................................... 1

Specifications ................................................................... 2

Ordering Information ........................................................ 2

Setting .............................................................................. 6

Installer Setup .................................................................. 7

Operation .......................................................................... 12

Troubleshooting Guide (Table 11) .................................... 17

Wiring Diagram (Figures 14 and 15) ................................ 19

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

SPECIFICATIONS

IMPORTANT

The specifications given in this publication do not include normal manufacturing tolerances. Therefore, this unit might not exactly match listed specifications. This product is tested and calibrated under closely controlled conditions; minor performance differences can be expected if those conditions are changed.

Table 1. T7351 Thermostat Features

Maximum Stages

Model Application

T7351F Conventional or

Heat Pump

This model is down-selectable and can be configured to control fewer stages than the maximum allowed.

Heat pump applications for this model have a maximum of two heat stages and two cool stages.

Mounting Means:

Mounts on subbase. Subbase Mounts On:

Wall: Using two 5/8 in. long #6-32 screws (included). Outlet Box: Using sheet metal screws.

Clock Accuracy at 77° F (25° C): ±1 min./month (30 days).

Minimum Stage Operation Time (fixed):

Minimum On

Heat: 1 minutes. Cool: 3 minutes.

Minimum Off (Cool and Heat Pump): 1 minute.

Electrical Ratings:

Power: 24 Vac, 50/60 Hz.; 20 to 30 Vac, 50/60 Hz. Input:

Temperature: 20K ohms. Humidity: 0-10 Vdc. Outdoor: 3000 PTC. Discharge Air: 20K ohms. Occupancy Sensor: Dry contact switching 30 Vdc at 1 mA.

All Relay Outputs (at 30 Vac):

Running: 1.5A maximum. Inrush: 7.5A maximum.

System Current Draw (without load):

5 VA maximum at 30 Vac, 50/60 Hz.

NOTE: Relays are N.O. Single-Pole, Single-Throw (SPST).

3 (2)

Models: See Table 1.

Dimensions: Refer to Fig. 1.

Finish (color): Trident White.

Batteries: No batteries required

Features

3 (4)

Outdoor Sensor Wiring: Requires 18 gauge wire.

Humidity Ratings: 5% to 90% RH, noncondensing.

Emergency Heat Indication:

Display indicates when Emergency Heat is activated (Em).

Temperature:

Ratings:

Display Accuracy: ±1° F (±1° C). Setpoint:

Loss of Power: The thermostat maintains programmed times

NOTE: To achieve the 48-hour power-loss clock retention,

Approvals:

European Community Mark (CE) Listed. UL 873 Recognized, NEC Class 2. FCC Part 15 subpart J Class A. cUL.

Humidity, Occupancy, Outdoor, Discharge Air Capability

Operating Ambient: 30° to 110° F (-1° to 43° C). Shipping: -30° to +150° F (-34° to +66° C).

Range:

Heating: 40° to 90° F (4° to 32° C).

Cooling: 45° to 99° F (7° to 37° C). Deadband: 2° F (1° C). Default Settings: Refer to Table 2.

and temperatures for the life of the product. Clock and day information is retained for a minimum of 48 hours.

the T7351 must be powered for at least 5 minutes.

Auxiliary

RelayHeat Cool

Yes

ORDERING INFORMATION

When purchasing replacement and modernization products from your TRADELINE® wholesaler or distributor, refer to the TRADELINE® Catalog or price sheets for complete ordering number.

If you have additional questions, need further information, or would like to comment on our products or services, please write or phone:

1. Your local Honeywell Automation and Control Products Sales Office (check white pages of your phone directory).

2. Honeywell Customer Care

1885 Douglas Drive North

Minneapolis, Minnesota 55422-4386 In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Toronto, Ontario M1V 4Z9. International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 2. Default Setpoints.

Control Occupied Not Occupied Standby

Heating 70° F (21° C) 55° F (13° C) 67° F (19° C)

Cooling 75° F (24° C) 85° F (29° C) 78° F (26° C)

2-3/16 (56)

2-1/32

(52)

2-1/32

(52)

1-9/16

(40)

4-1/16

(104)

M22432

4-1/2 (114)

SUBBASE

1-5/8

(42)

6-3/4 (171)

2-3/8 (60)

3-1/4 (83)

6-9/16 (166)

1-5/8

(42)

Fig. 1. Thermostat and Subbase Dimensions

in inches (mm).

Accessories:

Duct Discharge Air Sensors:

C7041B (6 or 12 in. [152 or 305 mm]), C7041C (18 in. [457 mm]), C7041J (12 ft. [3.66 m] averaging), C7770A (8 in. [203 mm] probe).

Outdoor Air Sensors: C7089A, C7170A,

C7031G2014 (weatherproof).

Temperature Sensors (Remote): C7772A, TR21, TR22, TR23,

and TR24 series, TR21-WK, TR23-WK, T7771. Economizer Logic Modules: W7210, W7212, W7215, W7459. Humidity Sensors: H7625, H7635. Others:

209541B FTT network termination module.

209651A Vertical Mounting Hardware Wallplate Adapter

(Trident white). 50000452-001 Troubleshooting Cable. TG512 Universal Versaguard Thermostat guards.

INSTALLATION

When Installing this Product...

1. Read these instructions carefully. Failure to follow them

could damage the product or cause a hazardous condition.

2. Check ratings given in instructions and on the product to ensure the product is suitable for your application.

3. Installer must be a trained, experienced service technician.

4. After installation is complete, check out product operation as provided in these instructions.

CAUTION

Electrical Shock or Equipment Damage Hazard. Can shock individuals or short equipment circuitry.

Disconnect power supply before installation.

IMPORTANT

All wiring must agree with applicable codes, ordinances and regulations.

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 an old control. If you have questions, call Honeywell Customer Care Center at 1-800-468-1502.

Location

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.

Subbase

WHEN USED TO SENSE ROOM TEMPERATURE

Install the thermostat about 5 ft. (1.5 m) above the floor in an area with good air circulation at average temperature. (Refer to Fig. 3.)

WHEN NOT USED TO SENSE ROOM TEMPERATURE

When using the remote-mounted temperature (and humidity) sensor(s) to sense ambient conditions, install the thermostat in an area that is accessible for setting and adjusting the temperature and settings.

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

CAUTION

Equipment Damage Hazard. Can damage the TIM connection beyond repair.

Disconnect the TIM cable prior to opening or closing the thermostat cover.

NOTE: Allow sufficient clearance below the thermostat to

plug in the TIM cable.

Install the remote-mounted sensor(s) about 5 ft. (1.5 m) above the floor in an area with good air circulation at average temperature. (See Fig. 2.)

NOTE: Only TR21 models with neither setpoint adjustment

nor bypass can be used for temperature averaging.

YES

5 FEET

(1.5 METERS)

1. Position and level the subbase.

NOTE: A level wallplate is only for appearance. The

thermostat functions properly when not level.

2. Use a pencil to mark the mounting holes. (Refer to Fig. 6.)

3. Remove the subbase from the wall and drill two 3/16 in. (4.76 mm) holes in the wall (if drywall) as marked. For firmer material such as plaster or wood, drill two 7/32 in. (5.56 mm) holes.

4. Gently tap anchors (provided) into the drilled holes until flush with the wall.

5. Position the subbase over the holes, pulling wires through the wiring opening.

6. Loosely insert the mounting screws into the holes.

7. Tighten mounting screws.

SUBBASE

T4 T3

TR21

M4823A

Fig. 2. Typical Location of Thermostat or Remote-Mounted

Sensor.

IMPORTANT

To avoid electrical interference, which can cause erratic performances, keep wiring runs as short as possible and do not run thermostat wires adjacent to the line voltage electrical distribution systems. Use shielded cable (Belden type 8762 or equivalent for 2-wire). The cable shield must be grounded only at the controlled equipment case.

Mounting Subbase

The subbase mounts horizontally or vertically.

IMPORTANT

• When using the internal temperature sensor, the device must be mounted horizontally (with the LCD facing upwards). Precise leveling is not needed.

• When using remote sensors, thermostat mounting orientation does not matter.

Wall mounting (using standard drywall screws) is standard. Mounting to a 2 in.(50.8 mm) by 4 in. (101.6 mm) wiring box can be accomplished: — for a horizontal box, no extra hardware is required. — for a vertical box, part 209651A is required. — Mount to European standard wall box 2.4 in. (having 61 mm

between mounting screws in a horizontal line) with or without adaptive hardware.

TR21

M29184

Fig. 3. Four TR21 Sensors providing a Temperature

Averaging Network for T7351 Thermostat.

T7350 SUBBASE

T4 T3

TR21-A

THE TR21-A IS A 10K OHM SENSOR.

T4 T3

1 1

TR21-A

M29256

Fig. 4. Two TR21-A Sensors Providing a Temperature

Averaging Network for T7351 Thermostat.

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

SUBBASE

T4 T3

TR21

M29257

Fig. 5. Nine TR21 Sensors Providing a Temperature

Averaging Network for T7351 Thermostat.

WIRES THROUGH WALL

MOUNTING HOLES

WALL ANCHORS (2)

MOUNTING SCREWS

Fig. 6. Mounting the Subbase.

Wiring

CAUTION

Electrical Shock or Equipment Damage Hazard. Can shock individuals or short equipment circuitry.

Disconnect power supply before installation.

IMPORTANT

All wiring must comply with local electrical codes and ordinances.

M19608

Follow equipment manufacturer wiring instructions when available. Refer to the Wiring Diagram section for typical hookups. A letter code is located near each terminal for identification. Refer to Tables 3 for terminal designations.

1. Loosen subbase terminal screws and connect system wires.

2. Securely tighten each terminal screw.

3. Push excess wire back into the hole in the wall.

4. Plug the hole with nonflammable insulation to prevent

drafts from affecting the thermostat.

Table 3. T7351 Subbase for Three-stage Heat, Three-stage

Cool Systems.

Terminal

Conventional

RCaRC

Heat Pump

24 VAC Cooling transformer.

24 VAC Heating transformer.

Description

X X Common.

aux aux Auxiliary relay.

W1 O/B Conventional: Stage 1 heating relay.

Heat Pump: Changeover relay for heating (B) or

cooling (O)

W2 W1 Conventional: Stage 2 heating relay.

Heat Pump: 1st Stage auxiliary heat relay.

Y1 Y1 Conventional: Stage 1 cooling relay.

Heat Pump: Stage 1 compressor relay.

Y2 Y2 Conventional: Stage 2 cooling relay.

Heat Pump: Stage 2 compressor relay.

AS AS Discharge Air Sensor connection (1).

AS AS Discharge Air Sensor connection (2).

OS OS Outdoor Air Sensor connection (1).

OS OS Outdoor Air Sensor connection (2).

G G Fan relay.

T3 T3 TR20 Series Remote Sensor connection (1).

T4 T4 TR20 Series Remote Sensor connection (2).

T5 T5 TR20 Series Remote Sensor connection (5).

T6 T6 TR20 Series Remote Sensor connection (9).

T7 T7 TR20 Series Remote Sensor connection (7).

W3 W2 Conventional: Stage 3 heat or stage 4 cool relay.

Heat Pump: 2nd Stage auxiliary heat relay.

Y3 — Conventional: Stage 3 cooling relay.

HS HS Humidity Sensor connection (signal: 0-10 Vdc).

TR23-H connection (11)

HC HC

Humidity Sensor connection (common).

HP HP Humidity Sensor connection (power). TR23-H

connection (12)

M M Motion Sensor connection (1).

M M Motion Sensor connection (2).

NOTE: Maximum (and recommended) wire size is 18-gauge

(ø 1.02 mm). Do not use wire smaller than 22-gauge (ø 0.644 mm).

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Factory jumper between RC and RH for systems with one

transformer.

For changeover functional details, see Operation section.

HC connection is not needed when using a TR23-H sensor.

Mounting Thermostat on Subbase (Fig. 7)

With the subbase installed, mount the thermostat:

1. Engage the tabs at the top of the thermostat and subbase.

2. Swing the thermostat down.

3. Press the lower edge of the case to latch.

SETTING

Using Thermostat Keys

The thermostat keys are used to:

• set current time and day,

• program times and setpoints for heating and cooling,

• override the program temperatures,

• display present setting,

• set system and fan operation,

• perform simple configuration.

NOTE: Refer to Fig. 8 for keypad information.

NOTE: To remove the thermostat from the wall, first

pull out at the bottom of the thermostat; then remove the top.

A. ENGAGE TABS AT TOP OF THERMOSTAT AND SUBBASE OR WALLPLATE.

B. PRESS LOWER EDGE OF CASE TO LATCH.

Setting Temperature

Refer to Table 2 for the default temperature setpoints. See Programming section for complete instructions on changing the setpoints.

Setting System and Fan

System default setting is Auto. Fan default setting is On.

NOTE: Use System and Fan keys to change settings.

System Settings

— Auto: Thermostat automatically changes between heating

and cooling based on indoor temperature. — Cool: Thermostat controls only cooling. — Off: Heating, cooling, and fan are all off. — Heat: Thermostat controls only heating. — Em Heat: Auxiliary heat serves as first stage. Compressor

stages are locked off.

Fan Settings.

— On: See Table 4. — Auto: Fan always cycles with call for heating or cooling.

— Conventional: The equipment (i.e. plenum switch)

controls fan operation in heat mode. The thermostat controls fan operation in cool mode.

— Electric Heat: The thermostat controls fan operation in

both heat and cool modes.

M19609

Fig. 7. Mounting Thermostat on Subbase.

63-2666—02 6

NOTE: Fan operation can extend (delay Off) after the

heating/cooling turns off:

— Heating choices are 0 or 90 seconds. — Cooling choices are 0 or 40 seconds.

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 4. T7351 Intelligent™ Fan ON control logic

Call for

Scheduled

Period

Occupancy

Motion Sensor

Signal

Effective

Occupancy Yes No

Heat/Cool

Notes

Occupied No Sensor Wired Occupied Fan On Fan On

Occupied Motion Sensed Occupied Fan On Fan On

Effective Occupancy is Standby. Standby

Occupied No Motion Sensed Standby Fan On

Fan Off

space is unoccupied. Fan is on only when there

setpoints are used and it assumes that the

is a call for heating or cooling.

Not Occupied No Sensor Wired Not Occupied Fan On

Not Occupied Motion Sensed Not Occupied Fan On

Not Occupied No Motion Sensed Not Occupied Fan On

In heat mode, when set for conventional heat, the equipment (i.e. plenum switch) could power the fan despite the T7350.

Fan Off

Occupancy sensor will only be active during scheduled Occupied periods. During scheduled

Not Occupied periods, the effective occupancy will always be Not Occupied.

Temperature

Occupied

HEAT HEATCOOL COOL

Not Occupied

Schedule

Start Time

Fig. 8. Thermostat Key Locations.

INSTALLER SETUP

For most applications, the thermostat factory settings do not need to be charged. Review the factory settings in Table 2.

NOTE: When power is first applied to the thermostat, the

display will show all segments (See Fig. 9).

Temporary Standby Not Occupied12

System

StartTime

MonTueWedTh uFri

Set ScheduleSet

EmHeat Off Cool Auto

Fig. 9. LCD Display of all Segments.

AM PM

SatSunHol

Dehumid OnAuto

Room

MinsDays

Fan

M19611

Clear

Set Day/Time

Day Time

HEAT COOL

CopyNot OccupiedOccupiedDay

System Fan

Override

Temporary

Occupied

ON AUTO

Tem po rar y

Not Occupied

Run

Schedule

M19610

Setup Using Keypad

The installer uses the Installer Setup to customize the thermostat to specific systems.

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

1. To enter the Installer Setup, press and hold both the Run Schedule and the Copy keys until DEGREES 00 (or

DEGREES 01) displays.

NOTE: Installer Setup will display WAIT and is

unavailable for 30 seconds after power up.

2. To advance to the next Installer Setup number, press

CAUTION

Possible Equipment Damage. Fan must be running when system is operating.

Heat pump and electric heat systems must be configured correctly to prevent equipment damage caused by the system running without the fan.

NOTE: Pressing Run/Copy again while in this mode

displays the T7351 firmware version number.

3. To return to a Setup item, cycle through the options.

4. To change a setting, use the up

or down  key.



5. To exit the Installer Setup, press Run Schedule.

6. Display prompts SAV CFG (save configuration).

7 63-2666—02

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

a. If you want to save the new configuration, use the up

or down  key to change NO to YES before



pressing Run Schedule.

b. If you want the configuration to remain as it was

before starting this change, ensure the display indicates SAV CFG NO and press Run Schedule.

NOTE: Installer Setup is automatically exited after five

minutes with no key pressed. Upon this automatic exit, all changes are lost.

Configuration

Configuration can be done with the keypad using the Installer Setup (ISU).

Table 5. Installer Setup.

Text Default Choices Notes

DEGREES 0 0 -1 Degree Temperature Format

CLOCK 0 0 - 1 Clock Display Format

KEYLOCK 0 0 - 3 Keypad Lockout Level

HEATPMP 0 0 - 2 Application Type Selection

COOLSTG 1 0 - 4 Number of Cooling Stages

HEATSTG 1 0 - 3 Number of Conventional Heating Stages (Not available if Heat Pump is selected)

AUX STG 0 0 - 2 Number of Heat Pump Heating Stages (Only shown when Heat Pump is selected)

AUX CON 0 0 - 3 Aux Contact Functionality

WALLMOD 0 0 - 3 Remote Room Sensor Selection

0: Degrees F 1: Degrees C

0: 12 hour 1: 24 hour

0: None 1: Lockout all keys except Set Day, Set Time, Set Date, Set Holidays, Temporary Occupied, Temporary Not Occupied, System, Fan, Up, Down and Information 2: Lockout all keys except Set Day, Set Time. Set Date, Set Holidays, Temporary Occupied, Temporary Not Occupied, Up, Down and Information 3: Lockout all keys except Information

0: Conventional 1: Heat Pump - Cooling (Energize O/B on call for cool) 2: Heat Pump - Heating (Energize O/B on call for heat)

0: 0 Stages of Cooling 1: 1 Stages of Cooling 2: 2 Stages of Cooling 3: 3 Stages of Cooling (Not available if Heat Pump is selected) 4: 4 Stages of Cooling (W3 will be used as 4th stage relay) (Not available if Heat Pump is selected)

0: 0 Stages of Heating 1: 1 Stages of Heating 2: 2 Stages of Heating (This is the max if 4 cooling stages is selected) 3: 3 Stages of Heating

0: 0 Aux Stages 1: 1 Aux Stages 2: 2 Aux Stages

0: Time of Day 1: Economizer 2: Dehumid - Hot Gas Bypass 3: Simple Dehumid

0: Local sensor only 1: TR21/TR24 and T7770A/D (Remote Sensor, No Remote Setpoint, Bypass 0) 2: TR22/TR23 and T7770B/C (Remote Sensor, Remote Setpoint, Bypass 0) 3: T7771 (Remote sensor, Remote Setpoint, Bypass 1) (Bypass 0 means that by pressing the override button the thermostat goes from unoccupied to occupied and the LED will light up and the temporary occupied timer will begin. If the button is pressed again, the timer will restart.) (Bypass 1 means that by pressing the override button a second time the thermostat can return to the unoccupied period.)

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 5. Installer Setup. (Continued)

Text Default Choices Notes

OATSENS 0 0 - 1 Outdoor Air Sensor Selection

0: None 1: Remote Outdoor Air Sensor

DATSENS 0 0 - 1 Discharge Air Sensor Selection

0: None 1: Remote Discharge Air Sensor

HUMSENS 0 0 - 2 Room Humidity Sensor selection

0: None 1: On Board Sensor 2: Remote Sensor

OCCSENS 0 0 - 1 Occupancy Sensor Selection

0: None 1: Remote Occ Sensor

FAN HT 0 0 - 1 Fan Operation on Heat

0: Conventional (Equipment controls Fan) 1: Electric (Thermostat turns on Fan with call for Heat)

XFAN HT YES YES or NO Extended Fan on Heat

NO: None YES: 90 seconds

XFAN CL NO YES or NO Extended Fan on Cool

NO: None YES: 40 seconds

STRTDEL 0 0 - 15 Sequential Start Delay

0 to 150 seconds in 10 second increments

ADVANCE NO YES or NO Advanced Settings

NO: Hide YES: Show

TMP LIM 3 0 - 5 Temporary Setpoint Adjustment

0: 0 Deg. F 1: 1 Deg. F 2: 2 Deg. F 3: 3 Deg. F 4: 4 Deg. F 5: 5 Deg. F

TMP OCC 3 1 - 8 Temporary Occupied Duration

1 to 8 hours

TMP CAL 0 -4 - 3 Temporary Display Adjustment

0 - 3 = 0 to 3 DDF 4 - 7 = -4 to -1 DDF

MINCOOL 45° F

(7° C)

MAXHEAT 90° F

(32° C)

45° - 99° F (7° - 37° C)

40° - 90° F (4° - 32° C)

Min Cool Setpoint

Max Heat Setpoint

HEATLCK NO YES or NO Heating Lockout (Only displayed if Outdoor Air Sensor is selected)

NO: None YES: Enabled

HTLCKSP 70° F

(21° C)

-40° - 120 ° F (-40° - 49° C)

Heating Lockout Temperature (Display only if Remote Outdoor Air Sensor is configured)

COOLLCK NO YES or NO Cooling Lockout (Only displayed if Outdoor Air Sensor is Selected)

NO: None YES: Enabled

CLLCKSP 35° F

(2° C)

-40° - 120° F (-40° - 49° C)

Cooling Lockout Temperature (Display only if Remote Outdoor Air Sensor is configured)

DAT LL NO YES or NO Discharge Low Limit (Only displayed if Discharge Air Sensor is Selected)

NO: None YES: Enabled

DATLLSP 45° F

(7° C)

35° - 60° F (2° - 16° C)

Discharge Low Temp Limit (Display only if Discharge Sensor is configured)

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 5. Installer Setup. (Continued)

Text Default Choices Notes

DAT HL NO YES or NO Discharge High Limit (Only displayed if Discharge Air Sensor is Selected)

DATHLSP 110° F

(43° C)

DEHUMID 0 0 - 5 Dehumidification

DEH MIN 5 5 - 15 Dehumidify Minutes On

DEH TMP 2 1 - 5 Dehumidify Temp Reset

MINHTRT 5 0 - 20 DDF/HR Minimum Heat Recovery Ramp Rate

MAXHTRT 8 0 - 20 DDF/HR Maximum Heat Recovery Ramp Rate (Only Displayed if Outdoor Sensor is Selected)

MINHTOA 0° F

(-18° C)

MAXHTOA 40° F

(4° C)

MINCLRT 3 0 - 20 DDF/HR Minimum Cool Recovery Ramp Rate

MAXCLRT 6 0 - 20 DDF/HR Maximum Cool Recovery Ramp Rate (Only Displayed if Outdoor Sensor is Selected)

MINCLOA 90° F

(32° C)

MAXCLOA 70° F

(21° C)

DSTMON1 3 0 - 12 DLS Spring Month

DSTDAY1 40 0 - 31, 32 - 74 DLS Spring Day

DSTMON2 11 0 - 12 DLS Fall Month

DSTDAY2 33 0 - 31, 32 - 74 DLS Fall Day

HT RESP 1 0 - 3 0: Standard - 3 cph

CL RESP 0 0 - 1 0: Standard - 3 cph

65° - 140° F (18° - 60° C)

-20° - 120° F (-29° - 49° C)

NO: None YES: Enabled

Discharge High Temperature Limit (Display only if Discharge Sensor is configured)

0: None 1: MinOn Time 2: Reset Temp Setpoint 3: Reset w/ MinOn 4: Reheat 5: Reheat w/ Min On

Minimum Heat Outdoor Air Temperature (Only Displayed if Outdoor Sensor is Selected)

Maximum Heat Outdoor Air Temperature (Only Displayed if Outdoor Sensor is Selected)

Minimum Cool Outdoor Air Temperature (Only Displayed if Outdoor Sensor is Selected)

Maximum Cool Outdoor Air Temperature (Only Displayed if Outdoor Sensor is Selected)

(DayLight Savings options only display when Date is valid)

0 - 31 = Day of Month 32 = Last Day of Month 33 = First Sunday etc…

1: Medium - 6 cph 2: Fast - 9 cph 3: Super Fast - 20 cph

1: Fast - 4 cph

Holidays and 365 - Day Clock

The T7351can be configured to schedule up to 10 separate holidays, each with a duration of up to 99 days. To enable this function, the user must set the date:

1. Press Set Day and Set Time keys simultaneously.

2. Use the Up/Down keys to set the date to YES, then

press the key.

3. Use the Up/Down keys to set the month, then press the key.

63-2666—02 10

4. Use the Up/Down keys to set the day, then press the key (Refer to Table 4 for valid day choices).

5. Use the Up/Down keys to set the year, then press the

key.

Holidays can be set in the following manner:

1. Press the “Temporary Occupied” and Temporary Not Occupied” keys simultaneously.

2. The month (MON) of the first holiday is then displayed (00 means the holiday is ignored).

3. Use the Up/Down keys to set the month, then press the

key.

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

4. Use the Up/Down keys to set the day, then press the key (Refer to Table 6 for valid day choices).

5. Use the Up/Down keys to set the duration.

Table 6. Valid Day Values.

Value Description Value Description

1 to 31 Day of month 42 Second Tuesday 53 Third Saturday 64 Fifth Wednesday

32 Last Day of Month 43 Second Wednesday 54 Fourth Sunday 65 Fifth Thursday

33 First Sunday 44 Second Thursday 55 Fourth Monday 66 Fifth Friday

34 First Monday 45 Second Friday 56 Fourth Tuesday 67 Fifth Saturday

35 First Tuesday 46 Second Saturday 57 Fourth Wednesday 68 Last Sunday

36 First Wednesday 47 Third Sunday 58 Fourth Thursday 69 Last Monday

37 First Thursday 48 Third Monday 59 Fourth Friday 70 Last Tuesday

38 First Friday 49 Third Tuesday 60 Fourth Saturday 71 Last Wednesday

39 First Saturday 50 Third Wednesday 61 Fifth Sunday 72 Last Thursday

40 Second Sunday 51 Third Thursday 62 Fifth Monday 73 Last Friday

41 Second Monday 52 Third Friday 63 Fifth Tuesday 74 Last Saturday

Table 7. T7351 Key Function Summary.

Grouping Button Definition

Information Down Arrow Lowers setpoint, day, or time. When setting times or temperatures, hold key down to

Information Obtains information (where humidity “high-limit” can be set), cycles through setup

Up Arrow Raises setpoint, day, or time. When setting times or temperatures, hold key down to

Temperature Occupied

Heat

Occupied Cool

Not Occupied Heat

Not Occupied Cool

Set Day Sets day of week. Tapping key with 'Set Value' segment on increases current day (same

Time Sets time. Tapping key with “Set Value” segment on increases time in one hour

Override Temporary

Occupied

Tem p or a ry No t Occupied

Schedule Day Selects day schedule to modify. (Used also with copy key.)



continuously decrease value. Also can make temporary change in temperature setpoint.

options.



continuously increase value. Also can make temporary change in temperature setpoint.

Sets Occupied Heat setpoint.

Sets Occupied Cool setpoint.

Sets Not Occupied Heat setpoint.

Sets Not Occupied Cool setpoint.

effect as Up Arrow key).

increments.

Temporary occupied setting for length of time defined by installer. User can modify setpoints.

Sets holiday length. User selects number of days (“0”-”99”), or “---” for continuous override.

The first holiday is now set and pressing the key will take you to programming the second holiday (denoted by the number 2 on the screen)

Occupied Selects occupied event start times for specified day. Repeatedly press this key to toggle

Not Occupied Selects not occupied event start times for specified day. Repeatedly press this key to

Clear Start Time Clears start time for specified period and day.

Copy Copies schedule from one day to another.

System Selects System Mode. Toggles through Em Heat, Off, Cool, and Auto.

between two occupied events.

toggle between two not occupied events.

11 63-2666—02

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 7. T7351 Key Function Summary. (Continued)

Grouping Button Definition

Schedule Fan

Selects fan operation mode. Toggles between On and Auto.

Run Schedule Resumes running schedule (cancels Temporary Occupied action, Holiday, and/or

On: Continuous fan operation during occupied periods. During not occupied periods and in standby mode when no motion is sensed, fan cycles with call for heat or cool. Auto: Fan cycles with call for heat or cool during all periods. (See Product Data Sheet, form 63-2605, for more details).

NOTES: The display returns to default screen after pressing Run Schedule (or after a period of time without keypress):

— ten seconds: when returning from temporary setpoint changes, info screen, temp occ, and temp not occ. — one minute: when returning from setting clock/day. — ten minutes: when returning from System Checkout. — five minutes: when returning from all other modes.

Special Functions

Restore Factory Configuration (Run/Clear)

IMPORTANT

Get Factory Schedule (Info/Clear)

Performing this operation reverts the schedules to the factory defaults:

Test Mode (Occupied/Not Occupied/ Schedule Day)

This operation erases current configuration and restores factory defaults for all configuration, parameters, setpoints and schedules. To regain the old requires device reconfiguration.

1. Press both Run Schedule and Clear Start Time.

2. The display gives the option to revert to FAC CFG.

a. To restore the factory defaults, press up

down

b. To cancel this option, ensure the display

3. Press Run Schedule.

1. Press both Info and Clear Start Time.

2. The display gives the option to revert to FAC SCH.

a. To restore the factory schedule, press up

b. To cancel this option, ensure display indicates NO.

3. Press Run Schedule.

until the display indicates YES.

indicates NO.

until the display indicates YES.

down

Temporary setpoint changes.)

NOTES:

Save User Schedule (Info/Copy)



Performing this operation saves the current schedule (including holidays) to memory, overwriting the old saved schedule:

Get User Schedule (Info/Run)

Getting the user schedule restores the schedule (including holidays) from saved memory, overwriting the schedule currently in use:

a. To enter test mode, press up

display indicates IN TEST.

b. To cancel this option, ensure display indicates NO

TEST.

3. Press Run Schedule.

— To verify whether or not the system test is still

active, repeat the above process.

— The system test times out after ten minutes with no

key pressed.

1. Press both Info and Copy.

2. The display gives the option to revert to SAV SHD.

a. To save the current schedule, press up

down

until the display indicates YES.

b. To cancel this option, ensure display indicates NO.

3. Press Run Schedule.

1. Press both Run Schedule and Info.

2. The display gives the option to GET SHD.

a. To retrieve the saved schedule, press up

b. To cancel this option, ensure display indicates NO.

3. Press Run Schedule

until the display indicates YES.

down

or downuntil the



CAUTION

Possible Equipment Damage. Equipment damage can result if compressor is cycled too quickly.

The minimum off time for compressors is bypassed during Test Mode. Equipment damage can occur if the compressor is cycled too quickly.

Use the Test Mode to check the thermostat configurations and operation. To start the system test:

1. Press Schedule Day, Occupied and Not Occupied simultaneously.

2. The display gives the option to TEST.

63-2666—02 12

OPERATION

Startup Operation

Upon initial thermostat power-up, a startup and initialization program begins. This startup occurs only on initial power-up. After total loss of power for an extended period, the current time and day can be lost (requiring reset). However, the thermostat retains the user program.

NOTE: With no program set, the thermostat controls to the

Occupied default setpoints of 70° F (21° C) for heat and 75° F (24° C) for cool.

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

T7351 Relay Logic

All T7351 model thermostats contain at least four switching relays. In conventional applications, the relays control first stage cooling, first stage heating, fan, and auxiliary. In heat pump applications, the relays control the heat pump compressor, changeover, fan, and emergency heat.

O/B Terminal for Heat or Cool Changeover

The O/B terminal controls heat pump changeover. The default operation is for the terminal to be powered when calling for heat (or while the most recent call was for heat). This corresponds to a typical B terminal.

NOTE: The O/B terminal can be configured to operate as a

typical O terminal (powered on call for cool).

Emergency Heat

With the system set for Em Heat, auxiliary heat serves as stage one; compressor stages are locked off. The fan cycles with the auxiliary heat.

Equipment Protection

As part of the operational sequence, the T7351 microprocessor incorporates cycle rate, and minimum on and off times for all heating and cooling stages. This extends equipment life as it prevents rapid cycling of equipment.

NOTE: Minimum on and off times are fixed.

Cycle Rates

The thermostat control algorithm maintains the temperature by cycling stages of heating or cooling to meet setpoint. Cycle rates, in cycles per hour (cph) are set in the installer setup.

NOTE: In the items that follow, the term “error” refers to the

difference between the measured space temperature and the current actual space temperature setpoint:

— The Throttling Range (TR), also called Proportional Gain,

determines the impact of the error on the output signal. Decreasing TR amplifies the error effect; that is, for a given error, smaller TR causes higher output signal.

— The Integral Time (IT), also called Integral Gain,

determines the impact of the error-over-time on the output signal. Error-over-time has two components making up its value: amount of time the error exists; and size of the error. The higher the IT, the slower the control response. In other words, a decrease in IT causes a more rapid change to the output signal.

— The Derivative Time (DT), also called Derivative Gain,

determines the impact of the error rate on the output signal. The error rate is how fast the error value changes. It can also be the direction the space temperature is going, either toward or away from the setpoint, and its speed—rapid or slow. A decrease in DT causes, for a given error rate, a greater effect on output signal.

Recovery Ramping Logic

The T7351 incorporates a ramping feature that gradually changes the space setpoints. During recovery operation, the setpoint changes at a rate in degrees per hour depending on the outdoor air temperature. If there is no outdoor air temperature sensor available, the minimum ramp rate is used.

When recovering in heating, the control point raises gradually, maximizing the use of the more economical first stage heat to bring the sensed temperature to the desired comfort setpoint. This minimizes using the typically more expensive later stage(s) of heat.

NOTE: See Fig. 10 for a pictorial representation of the heat

ramp rate determination.

NOTE: Defaults are: heat: 6cph, cool: 3cph.

P+I+D Control

The T7351 microprocessor-based control requires that the user understands temperature control and thermostat performance. A conventional electromechanical or electronic thermostat does not control temperature precisely at setpoint. Typically, there is an offset (droop) in the control point as the system load changes. This is a phenomenon that most people in the industry know and accept.

IMPORTANT

• P+I+D (Loop Tuning) parameters are optimized for proper operation of a vast majority of HVAC systems. Only when completely certain of necessary and proper changes should you alter these values.

• Improper changes result in poor system performance and equipment problems such as compressor short cycling. Other problems include wide swings in space temperature and excessive overdriving of modulating outputs.

All adjustments to Loop Tuning parameters should be gradual. After each change, allow the system to stabilize to accurately observe the effects of the change. Then, as needed, make further refinements until the system operates as desired.

If adjustment of PID parameters is required, use the following:

Recovery Ramping for Conventional Systems

HEAT RECOVERY RAMP RATE (DEGREES/HOUR)

MaxHtRamp

MinHtRamp

OUTDOOR AIR TEMPERATURE

OaTempMinHtRamp OaTempMaxHtRamp

Fig. 10. Heat Setpoint Ramping for Conventional Systems.

NOTES:

M10109

13 63-2666—02

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

— Recovery ramping applies between scheduled

heat or cool setpoint changes from not occupied to standby and not occupied to occupied.

— Other setpoint changes use a setpoint step

change.

Recovery Ramping for Heat Pump Systems

During recovery with heat pump equipment, the heating setpoint is split into a heat pump setpoint for compressors, and two auxiliary heat setpoints for the auxiliary heat stages. (Refer to Fig. 11 for the various setpoints.)

OCCUPIED SETPOINT

NOT OCCUPIED

SETPOINT

RECOVERY TIME

Fig. 11. Heat Setpoint Ramping for Heat Pump Systems.

Heat pump ramping for heating proceeds as follows:

1. The heat pump setpoint begins to ramp until the room

temperature and the compressor ramp intersect.

2. At this point, the heat pump setpoint performs a step change to the Occupied (or Standby) setpoint and all auxiliary heat stages are disabled.

NOTE: The heat pump setpoint remains here for the

rest of the Not Occupied period.

HEAT PUMP SETPOINT (FOR COMPRESSORS)

NORMAL RECOVERY RAMP

AUX HEAT STAGE 2 RAMP

AUX HEAT STAGE 1 RAMP

SPACE TEMPERATURE

OCCUPIED

TIME

M19877

NOTE: The setpoint used during the cool recovery period is

similar to the heat mode in Fig. 10, except the slope of the line reverses for cooling.

COOL RECOVERY RAMP RATE (DEGREES/HOUR)

MaxClRamp

MinClRamp

OUTDOOR AIR TEMPERATURE

OaTempMinClRamp OaTempMaxClRamp

M10111A

Fig. 12. Setpoint Ramping Parameters with Ramp Rate

Calculation.

Advantages:

• Comfort setting is achieved at the programmed time and maintained regardless of weather conditions; occupants are comfortable.

• Drafts from low-temperature discharge air are minimized during Occupied periods.

• Use of the more economical first stage of heat is maximized during recovery, minimizing use of the expensive later heat stage(s).

• Comfort and energy savings can be achieved in both heating and cooling.

• Heat cycling reduced, extending equipment life.

Auxiliary Relay

The auxiliary relay can be used with a variety of controls:

• Time-of-day (TOD).

• Economizer minimum position control.

• Dehumidification (see Dehumidification section).

3. The stage one auxiliary heat ramp is calculated based on a steeper slope starting 1° F (0.5° C) below the not occupied setpoint.

4. When the room temperature intersects this auxiliary heat ramp, the first stage of auxiliary heat is enabled.

5. The stage two auxiliary heat ramp is calculated based on an even steeper slope starting 2° F (1° C) below the not occupied setpoint.

6. When the room temperature intersects this auxiliary heat ramp, the second stage of auxiliary heat is enabled.

During the cool recovery period, the setpoint changes at a rate in degrees per hour relative to the outdoor air temperature. If there is no outdoor air temperature sensor available, the minimum ramp rate is used.

See Fig. 12 for the various setpoints.

NOTE: For cooling, the same method is used in both

conventional and heat pump systems.

63-2666—02 14

Relay for Time-Of-Day (Table 8)

Time-of-day (TOD) is the Auxiliary Relay default configuration. TOD logic operates strictly according to programming: — Occupied: Relay contacts closed. — Not Occupied: Relay contacts open. — Standby (Scheduled): Relay contacts closed.

Relay for Economizers

Mechanical cooling is often used with outside temperatures in the 50° F (10° C) to 60° F (16° C) range and humidity below 50 percent. In central and northern climates, hundreds of hours fall into this temperature category. By permitting 80 to 100 percent outside air into the system, mechanical cooling may not be needed at all, particularly during Spring and Fall.

Economizers take advantage of outside air. The typical economizer consists of an outside air damper, motor, outdoor air changeover control and a minimum position potentiometer. The motor controls the dampers. Suitability of the outside air for cooling is determined by the outdoor air changeover

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

control. The potentiometer adjusts the minimum position of the economizer dampers, which provide a minimum amount of fresh air for ventilation.

The economizer reduces compressor run time, thereby saving energy and extending compressor life. The drawback to using the economizer is that during the Not Occupied period, if there is no call for cool or outdoor air is not suitable for free cooling, the economizer is controlled to minimum position. This position allows some percentage of outdoor air to enter the building, regardless of air suitability. The situation can cause the heating or cooling to run more often than when only suitable air is permitted to enter the building.

Table 8. T7351 Auxiliary Relay Logic (Economizer and TOD)

Occupancy Auxiliary Contacts

Scheduled

Period

Occupied No Sensor

Occupied Motion Sensed Occupied

Occupied No Motion

Not Occupied No Sensor

Not Occupied Motion Sensed Not

Not Occupied No Motion

Motion Sensor

Signal

Wired

Sensed

Wired

Sensed

Effective

Occupancy Economizer TOD

Occupied

Closed

Standby Open; Closed only

during calls for cool

Not

Occupied

Open; Closed only

during calls for cool

Open; Closed only

Occupied

Not

Occupied

during calls for cool

Open; Closed only

during calls for cool

The T7351 can take advantage of an economizer by closing the auxiliary relay contacts to control the economizer minimum position potentiometer. (See Table 8 for details.)

— Powered: Allows normal economizer operation. — Unpowered: Disables the economizer minimum position.

The lack of power causes the economizer to drive dampers fully closed instead of staying at minimum open position. This reduces the possibility of unsuitable outdoor air entering the building, which lowers the internal load on the HVAC system and saves additional energy.

Notes

Closed

Open Effective Occupancy is Standby. Standby

setpoints are used and it assumes that the space is unoccupied. Economizer relay is energized only on calls for cooling.

Open

Occupancy sensor will only be active during

Open

scheduled Occupied periods. During scheduled Not Occupied periods, the effective occupancy will always be Not Occupied.

Open

Unless otherwise, noted, Economizer logic ignores calls for heat. The Economizer relay will be energized during calls for cooling.

b With fan set to AUTO and call for neither heat nor cool, the relay is open in order to disable damper minimum position.

Other Uses for the Auxiliary Relay

Examples of other uses of the auxiliary relay are hot water heaters, lighting, or baseboard heat. The additional loads are connected to the auxiliary relay contacts on the subbase. The contacts are rated for 1.5A at 30 Vac, but can be adapted to higher current applications using an external relay (See Fig. 13).

T7350A,B,D,M SUBBASE

AUX

AUXILIARY RELAY CONTACT

RELAY REQUIRED (R8222 OR SIMILAR).

TO LOAD

M19613

Default Auxiliary Relay Operations

Unless configured as a stage of heating or cooling, terminals W2, W3, and Y3 operate for specific auxiliary functions. Each output takes on different auxiliary functions depending on configuration for Conventional or Heat Pump operation. See Table 9 for details.

NOTE: The default functions cannot be modified. They are

limited to firmware version 1.3.0 or higher.

Fig. 13. Using T7351 Models with an External Relay (with

loads greater than 1.5A).

15 63-2666—02

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 9. Default Auxiliary Relay Operations.

Heat Pump or

Conventional

Contact Not Used as

Heat or Cool Stage Contact Configuration of Contact Not Used as Stage

Heat Pump Y3 Simple

Dehumidification

W2 not aux heat Economizer Time of Day Economizer Economizer

Conventional W3 not Simple

Dehumidification

Y3 not (W3 not) Economizer Time of Day Time of Day Economizer

Y3 not (W3 used) Simple

Dehumidification

Simple

Dehumidification

Simple

Dehumidification

Simple

Dehumidification

Time of Day Time of Day

Simple

Dehumidification

Simple

Dehumidification

Time of Day

Auxiliary Contact Configuration Time of Day Economizer Hot Gas Bypass

Dehumidification

Simple dehumidification uses a normally closed contact. The relay is closed when humidity is below the high limit. When the

Simple Dehumidification

humidity is above the high limit, the contact is open.

Dehumidification

There are five methods through which the T7351 can control for dehumidification. Three of them modify the control algorithm, thus providing limited dehumidification through cooling. The other two use the auxiliary output to control another device.

NOTE: The dehumidification high limit can be set within the

range of 10 to 90 percent relative humidity.

IMPORTANT

At times during Reheat dehumidification, the T7351 operates heating and the cooling simultaneously. This is normal.

NOTES:

— The heat stage never energizes during Reheat if

more than one cool stage is on.

— Reheat mode cannot occur during heating.

RESET TEMP SETPT

Control Through Cooling

Configure using some combination of the following: — Minimum On. — Reheat. — Reset.

NOTES:

— These methods operate only during cooling. — Selecting both Reheat and Reset can cause

frequent setpoint adjustments. This selection is not recommended.

MIN ON TIME

Dehumidifies by increasing the compressor minimum on time (normally 3 minutes) by a programmable amount. This is useful

The room temperature set point resets to a specified number of degrees below the actual set point when room relative humidity (RH) rises above humidity high limit. The default value is 2 degrees.

Though this may not technically reduce RH, it reduces the dew point to provide the customer with a sense of comfort due to a lower temperature setting in the room.

As long as RH stays above humidity high limit, this set point is maintained.

NOTE: Hysteresis and a minimum timer prevent the set point

from short interval alternation (between standard and reset set points).

with oversized systems in that it forces the coils to cool to a point where dehumidification can occur.

Options Utilizing Auxiliary Output

There are two dehumidification options that utilize the auxiliary

NOTES:

— Can force wider temperature swings by cooling

when setpoint control does not require it.

output. They are: — Simple Dehumidification. — Hot Gas Bypass Dehumidification.

— The minimum on time can be set within the range

of 5 to 15 minutes.

— Hysteresis and a minimum timer are used to

ensure this behavior does not change with every equipment cycle.

SIMPLE DEHUMID(IFICATION)

The auxiliary output: — Energizes when RH rises above humidity high limit. — De-energizes when RH drops below humidity high limit.

REHEAT

Dehumidifies by operating cooling during typical off time. The T7351 maintains the proper setpoint by running the heat at the same time.

63-2666—02 16

NOTES:

— 5% Hysteresis and a minimum timer prevent short

cycling of this output.

— Unlike Dehumid Hot Gas BP the relay remains

energized during calls for multiple cooling stages.

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

DEHUMID HOT GAS BP

The auxiliary output operates as shown in Table 10.

Table 10. Hot Gas Bypass Dehumidification Logic.

Humidity Cooling Stages Active Auxiliary Output

High more than one De-energized

High one or less Energized

Low more than one De-energized

Low one or less De-energized

Auxiliary output during call for multiple cooling stages for two reasons:

1. This method assumes that the cooling provides dehumidification.

2. Multiple cooling stages probably provide necessary dehumidification.

NOTE: Hysteresis and a minimum timer prevent short cycling

of this output.

TROUBLESHOOTING GUIDE (TABLE 11)

Table 11. Troubleshooting Information.

Symptom Possible Cause Action

Display will not come on.

Temperature display is incorrect.

Temperature settings will not change. (Example: Cannot set heating higher or cooling lower.)

Room temperature is out of control.

Thermostat is not being powered. Check that X terminal is connected to the system

transformer.

Check for 24 Vac between X and RH or RC terminals.

If missing 24 Vac:

• Check if circuit breaker is tripped; if so, reset circuit breaker.

• Check if system fuse is blown; if so, replace fuse.

• Check if the HVAC equipment power switch is in the Off

position; if so, set to the On position.

• Check wiring between thermostat and HVAC equipment. Replace broken wires and tighten loose connections.

If 24 Vac is present, proceed with troubleshooting.

Thermostat is configured for ° F or ° C display. Press both Run Schedule and Copy, then reconfigure the

display.

Bad thermostat location. Relocate the thermostat.

Display shows three dashes and a degree sign (all systems shut down).

Upper or lower temperature limits were reached.

Occupied setpoint temperature range stops were configured.

Keypad is locked. When a locked key is pressed, LOCKED appears momentarily on the LCD.

Remote temperature sensing is not working. Check all remote sensors.

T7351 is set for the remote sensing and sensor is missing or circuit is either open or shorted.

Check the temperature setpoints:

• Heating limits are 40° to 90° F (4° to 32° C)

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

Check setpoint stops. If necessary, reconfigure the stop(s).

Change keypad lock level.

17 63-2666—02

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 11. Troubleshooting Information. (Continued)

Symptom Possible Cause Action

Heat will not come on.

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

transformer.

Check for 24 Vac between X and RH terminals.

If missing 24 Vac:

• Check if circuit breaker is tripped; if so, reset circuit breaker.

• Check if system fuse is blown; if so, replace fuse.

• Check if the HVAC equipment power switch is in the Off

position; if so, set to the On position.

• Check wiring between thermostat and HVAC equipment. Replace broken wires and tighten loose connections.

If 24 Vac is present, proceed with troubleshooting.

Thermostat minimum off time is activated. • Wait up to five minutes for the system to respond.

• Configure heating response.

System selection is set to Off or Cool. Set system selection to Heat or Auto.

DAT high limit has been reached, or OAT lockout is engaged.

• If the setpoints are correct, do nothing.

• Adjust or disable DAT high limit and/or OAT lockout.

• Check HVAC equipment to ensure proper operation.

Cooling will not come on.

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

transformer. Check for 24 Vac between X and RC terminals. If missing 24 Vac:

• Check if circuit breaker is tripped; if so, reset circuit breaker.

• Check if system fuse is blown; if so, replace fuse.

• Check if the HVAC equipment power switch is in the Off

position; if so, set to the On position.

• Check wiring between thermostat and HVAC equipment. Replace broken wires and tighten loose connections.

If 24 Vac is present, proceed with troubleshooting.

Thermostat minimum off time is activated. • Wait up to five minutes for the system to respond.

• Configure cooling response.

System selection is set to Off or Heat. Set system selection to Cool or Auto.

DAT low limit has been reached, or OAT lockout is engaged.

• If the setpoints are correct, do nothing.

• Adjust or disable DAT low limit and/or OAT lockout.

• Check HVAC equipment to ensure proper operation.

System indicator (flame: heat, snowflake: cool) is displayed, but no warm or cool air is coming from the registers.

The call for heat or cool is not yet given. Check if any stage indicators (dots next to the system

indicator) are displayed. With no display of stage indicators, no call for cool/heat via relay is yet given.

Conventional heating equipment turns the fan on only after the furnace has warmed to a

Wait one minute after seeing the on indicator and then check the registers.

setpoint.

Heating or cooling equipment is not operating. Verify operation of heating or cooling equipment in Test

Mode.

63-2666—02 18

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

WIRING DIAGRAM (FIGURES 14 AND 15)

TR23-H REMOTE SENSOR

GND

SENSOR

SET PT

LED

HUMIDITY SENSOR

BYPASS

SUBBASE

T5 T6 T7 T4 T3

L1 (HOT)

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

ENSURE TRANSFORMER IS SIZED TO HANDLE THE LOAD.

HEAT/COOL SYSTEMS WITH ONE TRANSFORMER REQUIRE THE FACTORY-INSTALLED JUMPER.

USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION DIRECTIONS.

WHEN USING THE TR23-H FOR HUMIDITY SENSING THERE IS NO NEED TO WIRE HC TERMINAL

BECAUSE THE T3 TERMINAL IS INTERNALLY TIED TO HC, WHICH IS ALSO TIED TO TERMINAL 1 COMMON AT THE SENSOR.

OUTDOOR AIR SENSOR

MOTION SENSOR

DISCHARGE AIR SENSOR

OSOS ASAS

MHC HPHS

HEAT RELAY 3

W3/Y4 Y3 W2 Y2

RCX

AUXRH

ECONOMIZER

HEAT RELAY 2

W1 GY1

HEAT RELAY 1

COMPRESSOR CONTACTOR 1

COMPRESSOR CONTACTOR 2

COMPRESSOR CONTACTOR 3

FAN RELAY

M29255

Fig. 14. Typical Hookup of T7351F2010 in Three-Stage Heat and Three-Stage Cool Conventional System with One

Transformer.

TR23-H REMOTE SENSOR

GND

SENSOR

SET PT

LED

HUMIDITY SENSOR

BYPASS

SUBBASE

T5 T6 T7 T4 T3

L1 (HOT)

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

ENSURE TRANSFORMER IS SIZED TO HANDLE THE LOAD.

HEAT/COOL SYSTEMS WITH ONE TRANSFORMER REQUIRE THE FACTORY-INSTALLED JUMPER.

USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION DIRECTIONS.

WHEN USING THE TR23-H FOR HUMIDITY SENSING THERE IS NO NEED TO WIRE HC TERMINAL BECAUSE THE T3 TERMINAL IS INTERNALLY TIED TO HC, WHICH IS ALSO TIED TO TERMINAL 1 COMMON AT THE SENSOR.

OUTDOOR AIR SENSOR

MOTION SENSOR

DISCHARGE AIR SENSOR

OSOS ASAS

MHC HPHS

COMPRESSOR CONTACTOR 4

W3/Y4 Y3 W2 Y2

RCX

AUXRH

ECONOMIZER

HEAT RELAY 2

W1 GY1

HEAT RELAY 1

COMPRESSOR CONTACTOR 1

COMPRESSOR CONTACTOR 2

COMPRESSOR CONTACTOR 3

FAN RELAY

M29254

Fig. 15. Typical Hookup of T7351F2010 in Two-Stage Heat and Four-Stage Cool Conventional System.

19 63-2666—02

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

TR23-H REMOTE SENSOR

GND

SENSOR

SET PT

LED

BYPASS

HUMIDITY SENSOR

SUBBASE

T5 T6 T7 T4 T3

L1 (HOT)

HEATING TRANSFORMER

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

WHEN INSTALLED ON A SYSTEM WITH TWO TRANSFORMERS, REMOVE THE FACTORY-INSTALLED JUMPER.

USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION DIRECTIONS.

WHEN USING THE TR23-H FOR HUMIDITY SENSING, THERE IS NO NEED TO WIRE THE HC TERMINAL BECAUSE THE T3 TERMINAL IS INTERNALLY TIED TO HC, WHICH IS ALSO TIED TO TERMINAL 1 COMMON AT THE SENSOR.

OUTDOOR AIR SENSOR

MMHC HPHS

MOTION SENSOR

DISCHARGE AIR SENSOR

OS OS AS AS

AUX RH

CHANGEOVER

ECONOMIZER

AUX HEAT STAGE 1

W1W2 Y2

RC X

O/B G Y1

COMPRESSOR CONTACTOR 1

COMPRESSOR CONTACTOR 2

FAN RELAY

L1 (HOT)

COOLING TRANSFORMER

M29323

Fig. 16. Typical hookup of T7351F2010 in two-stage heat and two-stage cool heat pump system with two transformers.

Automation and Control Solutions

Honeywell International Inc.

1985 Douglas Drive North

Golden Valley, MN 55422

Honeywell Limited-Honeywell Limitée

35 Dynamic Drive

Toronto, Ontario M1V 4Z9

customer.honeywell.com

Honeywell T7351 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATION

SPECIFICATIONS

INSTALLATION

When Installing this Product...

Location

Mounting Subbase

Wiring

Mounting Thermostat on Subbase (Fig. 7)

SETTING

Using Thermostat Keys

Setting Temperature

Setting System and Fan

INSTALLER SETUP

Setup Using Keypad

Configuration

Holidays and 365 - Day Clock

Special Functions

OPERATION

Startup Operation

T7351 Relay Logic

O/B Terminal for Heat or Cool Changeover

Emergency Heat

Equipment Protection

Recovery Ramping Logic

P+I+D Control

Recovery Ramping for Conventional Systems

Recovery Ramping for Heat Pump Systems

Auxiliary Relay

Dehumidification

TROUBLESHOOTING GUIDE (TABLE 11)

WIRING DIAGRAM (FIGURES 14 AND 15)