Honeywell T7351 User Manual 2

T7351 Commercial Programmable Thermostat

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

INSTALLATION INSTRUCTIONS

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 display and keypad for 7-day programming. The subbase includes equipment control connections. The subbase mounts on the wall and the thermostat mounts to the subbase.

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.

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.

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.

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. The cable shield must be grounded only at the controlled equipment case.

Subbase

WHEN USED TO SENSE ROOM TEMPERATURE

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

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.

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

If multiple remote sensors are required, they must be arranged in a temperature averaging network consisting of four sensors (See Fig. 2).

NOTE: Only T7770 models with no setpoint adjustment

can be used for temperature averaging.

62-0258

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

YES

5 FEET

(1.5 METERS)

T4 T3

T7770A

SUBBASE

T7770A

Fig. 1. Typical location of thermostat or

remote-mounted sensor.

Mounting Subbase

The subbase mounts horizontally.

IMPORTANT

• When using the internal temperature or humidity

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

• When using remote room temperature and

humidity sensors, thermostat mounting orientation does not matter.

Wall mounting (using standard drywall screws) is standard. Mounting to a 2 in. by 4 in. (50.8 mm by 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 (having 2.4 in.

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

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. (See Fig. 3).

3. Remove the subbase from the wall and drill two 3/ 16 in. (4.8 mm) holes in the wall (if drywall) as marked. For firmer material such as plaster or wood, drill two 7/32 in. (5.6 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.

MOUNTING HOLES

T7770A

M19606A

T7770A

M4823A

Fig. 2. Four T7770A Sensors providing temperature

averaging network for T7351 Thermostat.

WALL ANCHORS (2)

WIRES THROUGH WALL

Fig. 3. Mounting the subbase.

Mounting Thermostat on Subbase (Fig. 4)

With the subbase installed, mount the thermostat:

1. Engage top subbase tabs into the thermostat top.

2. Swing the thermostat down.

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

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

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

MOUNTING SCREWS

M19608

62-0258 2

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

ENGAGE TABS AT TOP OF THERMOSTAT AND SUBBASE OR WALLPLATE.

PRESS LOWER EDGE OF CASE TO LATCH.

M19609

Fig. 4. Mounting thermostat on subbase.

Wiring

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.

IMPORTANT

All wiring must comply with local electrical codes and ordinances.

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

gauge. Do not use wire smaller than 22-gauge.

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 pre-

vent drafts from affecting the thermostat.

SETTINGS

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.

NOTE: See Fig. 5 for keypad information.

Setting Temperature

Refer to Table 2 for the default temperature setpoints. To set the Occupied and Not Occupied Heat and Cool setpoints, simply press the Heat and Cool button under the Occupied or Not Occupied area of the keypad. To set the Standby Heat setpoint, press both the Occupied and Not Occupied Heat buttons simultaneous. To set the Standby Cool setpoint, press the Occupied Cool and Not Occupied Heat buttons simultaneously.

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 cooling. — Off: Heating, cooling, and fan are all off. — Heat: Thermostat controls heating. — Em Heat: Auxiliary heat serves as first stage.

Compressor stages are locked off.

Fan Settings

— On: See Table 1. — Auto: Fan always cycles with call for heat or cool.

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

controls fan operation in heat mode. Thermostat controls fan operation in cool mode.

— Electric Heat: Thermostat controls fan operation in

both heat and cool modes.

NOTES: 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.

Table 1. Fan On Control Logic.

Occupancy Call for Heat/Cool

Scheduled Sensor Signal Yes No

Occupied Occupied On On

Occupied Standby On

Standby — On On

Not Occupied — On

In heat mode, when set for conventional heat, the equipment (i.e. plenum switch) could power the fan despite the T7351.

Off

3 62-0258

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Temperature

Occupied

HEAT HEATCOOL COOL

Not Occupied

Schedule

Clear

Start Time

Fig. 5. Thermostat key locations.

INSTALLER SETUP

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

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

display will show all segments (see Fig. 6).

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)

Temporary Standby Not Occupied12

System

EmHeat Off CoolAuto

StartTime

MonTue WedTh uFri

Set ScheduleSet

SatSunHol

Dehumid OnAuto

AM PM

Room

MinsDays

Fan

M19611

Fig. 6. LCD display of all segments.

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.

Set Day/Time

Day Time

HEAT COOL

CopyNot OccupiedOccupiedDay

System Fan

Override

Temporary

Occupied

ON AUTO

Temp or ar 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 feature:

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 .

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).

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.

62-0258 4

Configuration

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

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 3. 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 Heating Stages

AUX STG 0 0 - 2 Only shown when Heat Pump is selected

AUX CON 0 0 - 3 Aux Contact Functionality

WALLMOD 0 0 - 3 Remote Room Sensor Selection

OATSENS 0 0 - 1 Outdoor Air Sensor Selection

DATSENS 0 0 - 1 Discharge Air Sensor Selection

HUMSENS 0 0 - 2 Room Humidity Sensor selection

OCCSENS 0 0 - 1 Occupancy Sensor Selection

FAN HT 0 0 - 1 Fan Operation on Heat

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 4: 4 Stages of Cooling (W3 will be used as 4th stage relay)

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: T7770A/D (Remote Sensor, No Remote Setpoint, Bypass 0) 2: T7770B/C (Remote Sensor, Remote Setpoint, Bypass 0) 3: T7771 (Remote sensor, Remote Setpoint, Bypass 1) (Display only if sub-base 2, 3, 4+) (This item is not displayed when

0: None 1: Remote Outdoor Air Sensor

0: None 1: Remote Discharge Air Sensor

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

0: None 1: Remote Occ Sensor

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

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 3. Installer Setup. (Continued)

Text Default Choices Notes

XFAN HT YES YES or NO Extended Fan on Heat

XFAN CL NO YES or NO Extended Fan on Cool

STRTDEL 0 0 - 15 Sequential Start Delay

ADVANCE NO YES or NO Advanced Settings

TMP LIM 3 0 - 5 Temporary Setpoint Adjustment

TMP OCC 3 1 - 8 Temporary Occupied Duration

TMP CAL 0 -4 - 3 Temporary Display Adjustment

MINCOOL 45° F

MAXHEAT 90° F

(7° C)

(32° C)

45° - 99° F (7° - 37° C)

40° - 90° F (4° - 32°)

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

HTLCKSP 70° F

(21° C)

-40° - 120 ° F (-40° - 49° F)

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

CLLCKSP 35° F

(2° C)

-40° - 120° F (-40° - 49° C)

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

DATLLSP 45° F

(7° C)

35° - 60° F (2° - 16° C)

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

DATHLSP 110° F

(43° C)

65° - 140° F (18° - 60° C)

DEHUMID 0 0 - 5 Dehumidification

NO: None YES: 90 seconds

NO: None YES: 40 seconds

0 to 150 seconds in 10 second increments

NO: Hide YES: Show

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

1 to 8 hours

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

Min Cool Setpoint

Max Heat Setpoint

NO: None YES: Enabled

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

NO: None YES: Enabled

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

NO: None YES: Enabled

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

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

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

MINHTOA 0° F

(-18° C)

-20° - 120° F (-29° - 49° C)

Selected)

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

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 3. Installer Setup. (Continued)

Text Default Choices Notes

MAXHTOA 40° F

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

MINCLOA 90° F

MAXCLOA 70° F

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

(4° C)

(32° C)

(21° C)

-20° - 120° F (-29° - 49° C)

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

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.

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

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

Table 4. Valid Day Values.

Value Description Value Description 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

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.

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

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

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).

7 62-0258

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 5. T7351 Key Function Summary.

Grouping Button Definition

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

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

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

Temperature Occupied

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

Override Temporary

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

Heat

Occupied Cool

Not Occupied Heat

Not Occupied Cool

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

Occupied

Temporary Not Occupied

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

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

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

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

setup options.

down to 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.

day (same effect as Up Arrow key).

hour 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.

key to toggle between two occupied events.

this key to toggle between two not occupied events.

Copy Copies schedule from one day to another.

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

Fan

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

On: Continuous fan operation (occupied and standby). During not occupied periods, 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.

Selects fan operation mode. Toggles between On and Auto.

and/or Temporary setpoint changes.)

Special Functions

Restore Factory Configuration (Run/Clear)

IMPORTANT

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

62-0258 8

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 ! or

down " until the display indicates YES.

b. To cancel this option, ensure the display

indicates NO.

3. Press Run Schedule.

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Get Factory Schedule (Info/Clear)

Performing this operation reverts the schedules to the factory defaults:

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 ! or

down " until the display indicates YES.

b. To cancel this option, ensure display indicates

NO.

3. Press Run Schedule.

Test Mode (Occupied/Not Occupied/Schedule Day)

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. a. To enter test mode, press up ! or down " until

the display indicates IN TEST.

b. To cancel this option, ensure display indicates

NO TEST.

3. Press Run Schedule.

NOTES:

— 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.

Save User Schedule (Info/Copy)

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

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 ! or

down " until the display indicates YES.

b. To cancel this option, ensure display indicates

NO.

3. Press Run Schedule.

Get User Schedule (Info/Run)

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

1. Press both Run Schedule and Info.

2. The display gives the option to GET SHD.

a. To retrieve the saved schedule, press up ! or

down " until the display indicates YES.

b. To cancel this option, ensure display indicates

NO.

3. Press Run Schedule

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.

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

NOTES:

— Can force wider temperature swings by cool-

ing when setpoint control does not require it.

— 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.

Reheat

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

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

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 set point.

Though this may not technically reduce relative humidity in the room, 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 set point, 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).

9 62-0258

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Options Utilizing Auxiliary Output

There are two dehumidification options that utilize the auxiliary output. They are: — Simple Dehumidification. — Hot Gas Bypass Dehumidification.

Simple Dehumid(ification)

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

limit.

NOTES:

— 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.

Dehumid Hot Gas BP

The auxiliary output operates as shown in Table 6.

Table 6. 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.

3. Hysteresis and a minimum timer prevent short cycling of this output.

WIRING DIAGRAMS

OUTDOOR

HUMIDITY SENSOR

AIR SENSOR

123456789

MMHC HPHS

MOTION SENSOR

DISCHARGE AIR SENSOR

OSOS ASAS

RCX

transformers.

AUX

W1 G

HEAT RELAY 1

ECONOMIZER

COMPRESSOR CONTACTOR 2

HEAT RELAY 2

W2 Y2

FAN RELAY

COMPRESSOR CONTACTOR 1

COOLING TRANSFORMER

L1 (HOT)

M25324

T7770 REMOTE 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.

Fig. 7. Typical hookup of T7351F2010 in two-stage heat and two-stage cool heat pump system with two

OUTDOOR

HUMIDITY SENSOR

AIR SENSOR

MOTION SENSOR

OSOS ASAS

MHC HP

DISCHARGE AIR SENSOR

123456789

T7770 REMOTE SENSOR

SUBBASE

T5 T6 T7 T4

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.

COMPRESSOR CONTACTOR 4

W3/Y4 Y3 W2

RCX

AUXRH

ECONOMIZER

HEAT RELAY 2

W1 G

HEAT RELAY 1

COMPRESSOR CONTACTOR 1

COMPRESSOR CONTACTOR 2

FAN RELAY

COMPRESSOR CONTACTOR 3

M19768A

Fig. 8. Typical hookup of T7351F201U in two-stage heat and four-stage cool conventional system.

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T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

MOTION SENSOR

OSOS ASAS

MHC HPHS

ECONOMIZER

DISCHARGE AIR SENSOR

HEAT RELAY 3

AUX

W3/Y4 Y3 W2 Y2

AUXRH

HEAT RELAY 2

HEAT RELAY 1

COMPRESSOR CONTACTOR 1

COMPRESSOR CONTACTOR 2

FAN RELAY

COMPRESSOR CONTACTOR 3

M25319

OUTDOOR

T7770 REMOTE SENSOR

SUBBASE

T5 T6 T7 T4 T3

W1 G

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.

Fig. 9. Typical hookup of T7350F2010 in three-stage heat and three-stage cool conventional system

AIR SENSOR

123456789

HUMIDITY SENSOR

with one transformer.

TROUBLESHOOTING GUIDE (TABLE 7)

Table 7. 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.

Thermostat is configured for °F or °C display.

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.

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.

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

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)

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

Press both Run Schedule and Copy, then change keypad lock level.

Check all remote sensors.

11 62-0258

T7351 COMMERCIAL PROGRAMMABLE THERMOSTAT

Table 7. Troubleshooting Information. (Continued)

Symptom Possible Cause Action

Heat will not come on.

Cooling will not come on.

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

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

Thermostat minimum off time is activated.

System selection is set to Off or Cool.

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

Thermostat minimum off time is activated.

System selection is set to Off or Heat.

The call for heat or cool is not yet given.

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

Heating or cooling equipment is not operating.

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.

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

• Configure heating response.

Set system selection to Heat or Auto.

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.

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

• Configure cooling response.

Set system selection to Cool or Auto.

Check if any stage indicators (dots next to the system indicator) are displayed. With no display of stage indicators, no call for cool/heat is yet given.

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

Verify operation of heating or cooling equipment in self-test.

Automation and Control Solutions

Honeywell International Inc. Honeywell Limited-Honeywell Limitée

1985 Douglas Drive North 35 Dynamic Drive

Golden Valley, MN 55422 Toronto, Ontario M1V 4Z9

customer.honeywell.com

Honeywell T7351 User Manual 2

Specifications and Main Features

Frequently Asked Questions

User Manual

APPLICATION

INSTALLATION

When Installing this Product...

Location

Mounting Subbase

Mounting Thermostat on Subbase (Fig. 4)

Wiring

SETTINGS

Using Thermostat Keys

Setting Temperature

Setting System and Fan

System Settings

Fan Settings

INSTALLER SETUP

Setup Using Keypad

Configuration

Holidays and 365 - Day Clock

Special Functions

DEHUMIDIFICATION

Control Through Cooling

Options Utilizing Auxiliary Output

WIRING DIAGRAMS

TROUBLESHOOTING GUIDE (TABLE 7)