Honeywell T8401C User Manual

Page 1

T8401C

Electronic Thermostats

INSTALLATION INSTRUCTIONS

APPLICATION

The T8401C Thermostat provides single-stage, nonprogrammable cooling systems with manual changeover from heat to cool. Heating cycle rate is selectable at 1, 3, 6, 9 or 12 cph. Cooling cycle reate is fixed at 3 cph. Temperature indicature indication can be set for °F or °C.

The T8401C1031 (Fig. 1) is powered directly from the zone panel. Batteries are not required because setpoints are held permanently by non-volatile memory.

T8401C models include a thermostat, wallplate (for wiring and mounting thermostat) and owner ’s guide. See Table 1 for a listing of thermostat features. See Table 2 for a listing of zone panels that can be used with the T8401C.

temperature control for 24 Vac heating

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

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

CAUTION

Damage to Heating/Cooling System Possible.

Be careful when handling wires during

Set

Room

FAN SYSTEM

Auto On

Fig. 1. The T8401C1031 Thermostat.

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.

Model Powering Method Changeover System Selection Fan Selection

T8401C1031 Hardwired Manual Heat-Off-Cool On-Auto

Cool Off Heat

M14752

Table 1. Thermostat Features

installation. Disconnect power at furnace or main breaker/ fuse box.

Location

Install the thermostat about 5 ft (1.5m) above the floor in an area with good air circulation at average temperature. See Fig. 2. 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 the sun or appliances. — concealed pipes and chimneys. — unheated (uncooled) areas such as an outside wall

behind the thermostat.

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T8401C ELECTRONIC THERMOSTATS

Table 2. Zone Panel Cross Reference.

TotalZone

(TZ-3)

MABS EZ

(EZ-2, EZ-4)

Mini Zone

(MM - 2, -3) MABS II, IIL

T8401C1031 Yes Ye s One Oher One Oher

Yes N o Yes No No

Independent

Zone

Fig. 2. Typical location of thermostat.

This thermostat is a precision instrument and was carefully adjusted at the factory. Handle it carefully.

Mounting Wallplate to Wall

IMPORTANT

Level only for appearance. The thermostat functions normally even when not level.

Mount wallplate, T8401C, and the screws provided (see Fig. 3) as follows:

1. Place the wallplate at the desired location on the wall.

2. Pull the thermostat wire through the wallplate entrance hole.

3. Select the two mounting holes that best fit the application.

4. Fasten the wallplate to the wall using the anchors and screws provided.

YES

5 FEET

[1.5 METERS]

5. After wiring the wallplate, plug the hole to prevent

M11338

drafts from affecting the thermostat; see Wiring section

WALL

MOUNTING SCREWS (2)

WHEN USING WALL ANCHORS, DRILL 3/16 INCH HOLES FOR DRYWALL, 7/32 INCH HOLES FOR PLASTER OR WOOD.

WALL ANCHORS (2)

WALLPLATE

M12202A

Fig. 3. Mounting wallplate to wall.

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T8401C ELECTRONIC THERMOSTATS

Setting Fan Operation (Fuel) Switch

The fan operation (fuel) switch is preset at the factory in the F position. See Fig. 4. This is the correct setting for most systems. If this system is an electric heat system, set the switch to the E position. The E setting allows the fan to turn on immediately with the heating or cooling equipment in a system where the G terminal is connected

FAN OPERATION (FUEL) SWITCH

M12580

Fig. 4. Fan operation (fuel) switch.

Wiring

IMPORTANT

Use an 18-gauge thermostat cable for proper wiring.

All wiring must comply with local electrical codes and ordinances. Disconnect the power supply to prevent electrical shock or equipment damage.

NOTE: NOTE: To ensure proper mounting of thermo-

stat, restrict all wiring to the shaded area. See Fig. 5.

The shape of the terminals permits insertion of straight or wraparound wiring connections; either method is acceptable. See Fig. 6.

The T8401C is powered directly from the zone panel.

Refer to Fig. 7, 8, and 9 for typical wiring hookups.

KEEP WIRING IN SHADED AREA

MOUNTING SCREW HOLE

WIRING ENTRANCE HOLE

Fig. 5. Restrict wiring to shaded area.

FOR STRAIGHT INSERTION TERMINAL SCREW

STRIP 5/16 IN. (8 MM)

MOUNTING SCREW HOLE

M14286

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

M14287

Fig. 6. Wiring connections.

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T8401C ELECTRONIC THERMOSTATS

TOTAL ZONE MABS EZ PANEL

NO CONNECTION

T8401 THERMOSTAT

Fig. 7. T8401 with TotalZone or MABS EZ control

THERMOSTAT MOTOR

W2 L G Y R W M6 M4 M1

OBGYRWC

M14288

panels (all zones)

MM-2 OR MM-3 CONTROL PANEL

CHANGEOVER

CONTROL

O1 G1 B1 T6/Y T5/R T4/W M1 M4 M6

OG BYRWC

T8401 THERMOSTAT

THERMOSTAT

(ZONE 1)

DAMPER MOTOR

(ZONE 1)

NO CONNECTION

TO T8401

M14289

Fig. 8. T8401 with MM-2 or MM-3 panels (zone one).

MABS II OR MABS IIL CONTROL PANEL

CHANGEOVER

CONTROL

O1 G1 B1 T6 T5 T4 M1 M4 M6

OG BYRWC

T8401 THERMOSTAT

Fig. 9. T8401 with MABS II and MABS IIL control

THERMOSTAT

(ZONE 1)

panel (zone one).

DAMPER MOTOR

(ZONE 1)

NO CONNECTION

TO T8401

M14290

Mounting Thermostat to Wallplate

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

2. Swing down the thermostat and press the lower edge of the thermostat onto the wallplate to latch. See Fig. 10.

Auto On

Set

Room

ENGAGE TABS AT TOP OF THERMOSTAT WITH SLOTS ON MOUNTING PLATE.

Set

Room

DASHED LINES INDICATE TABS ON BACK OF THERMOSTAT

SYSTEM

Cool Off Heat

l O

ff H

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PRESS LOWER EDGE OF

CASE TO LATCH.

M14292

Fig. 10. Mounting thermostat to wallplate.

Removing Thermostat from Wallplate

1. Pull the lower edge of the thermostat away from the wall.

2. Swing the thermostat up and remove the wallplate.

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T8401C ELECTRONIC THERMOSTATS

SETTINGS AND ADJUSTMENTS

Setting FAN and SYSTEM Switches

Fan and system settings are controlled manually by using the switches located at the bottom of the thermostat case. See Fig. 11.

Set

FAN

FAN SWITCH

Fig. 11. Digital Display and System Switches.

FAN Switch

Fan switch settings are:

On: The fan runs continuously. Use for improved air

circulation and air quality.

Auto: Normal setting for most homes. In cooling, the

fan starts and stops with the cooling equipment. In heating, the fan is controlled directly by the heating equipment and may start a few minutes after the heating equipment turns on (on most systems). In electric heat applications, the zone panel can be configured to turn the fan on when the thermostat calls for heat.

Slide the FAN switch in the bottom left corner of the thermostat to select the desired fan setting.

SYSTEM Switch

System switch settings control thermostat operation as

follows: Cool: The thermostat controls the cooling system. The

O terminal is energized.

Off: Both heating and cooling are off. O and B termi-

nals are de-engergized.

Heat: The thermostat controls the heating system.

The B terminal is energized.

Slide the SYSTEM switch in the bottom right corner of the thermostat to select the desired system setting.

TEMPERATURE DISPLAY

Room

INCREASE SETTING

DECREASE SETTING

Cool Off Heat

SYSTEM SWITCH

SYSTEM

M14293

Set Temperature Setpoint

NOTE: NOTE: Temperature setpoint range is 40° to

99°F (5° to 37°C).

The temperature setpoint and the room temperature are shown separately on the digital display. The ▼ indicator points to Set when the temperature setpoint is displayed and to Room when the room temperature is displayed.

INDICATOR

ROOM TEMPERATURE

Room

Set

SETPOINT TEMPERATURE

To set temperature setpoint:

1. Select Heat or Cool by sliding the SYSTEM switch in the lower right corner of the thermostat to the desired mode. See Fig. 11.

2. To display the temperature setpoint on the digital display, press either the ▲ or ▼ key once. The temperature setpoint is displayed for approximately five seconds as the indicator points to Set and flashes.

3. To decrease the temperature setpoint press the ▲ key. Each press changes the setpoint one degree; press and hold to change the setpoint several degrees.

4. To increase the temperature setpoint press the ▼ key. Each press changes the setpoint one degree; press and hold to change the setpoint several degrees.

Setting

NOTE: NOTE: To save changes to the °F/°C indication

To set the °F/°C indication and heat cycle rate:

C Indication and Heat Cycle Rate

°F/°

and the heat cycle rate, all seven steps must be completed.

1. If the temperature is displayed in °F, set the temperature setpoint to 52°F. If the room temperature is displayed in °C, set the temperature setpoint to 11° C.

M14680

M14681

M14682

M14679

M14683

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T8401C ELECTRONIC THERMOSTATS

Optional System Checkout

When in steps 2 and 3 only, the ▼ key can be used to turn heat or cool outputs on and off. Change the SYSTEM switch setting to test heat or cool outputs. No action takes place If the SYSTEM switch is in the Off position.

Examples: System setting at HEAT: If heat is on, the

▼ key turns it off; if heat is off, ▼ turns it on.

System setting at COOL: If cool is on, ▼ key turns it

off; if cool is off, ▼ turns it on.

2. Press the ▲▼ keys simultaneously for more than

one second to light all segments on display and to enter installer setup mode. When the keys are released, a two-digit software revision code is displayed.

NOTE: NOTE: In installer setup mode only, each press

of the ▲ key momentarily displays 01. Each press of the ▼ key momentarily displays 02. When the keys are released, these two-digit codes are no longer displayed.

3. Press the ▲ key. Factory information is displayed.

A typical example is shown, but information displayed varies by model. This information is for factory use only.

4. Press the ▲ key again to display °C or °F.

5. Press the ▼ key to change the °C or °F indication.

M14684

M14685

M14686

M14687

M14688

scrolling when the desired cycle rate is displayed. See Table 3 for the cycle rate options and the corresponding system equipment.

M14690

Table 3. Heating Cycle Rates.

System Cycles Per Hour

Steam, Gravity 1

Hydronic Heat, Condensing Gas

Furnaces

Gas or Oil Forced Air 6

Electric Heat 9

Special Applications

High Efficiency Furnace.

Refer to equipment manufacturer’s instructions.

NOTE: NOTE: Steps 7 and 8 are available on select

models.

7. Press the ▲ key to display cooling algorithm con- figuration default.

8. Press the ▲ key again to change cooling algorithm to C1 or C3.

C1 = Standard cooling algorithm. C3 = Aggressive cooling algorithm (can cause

9. Press the ▲ key again. Current configuration (CC) is displayed. A typical example is shown, but CC varies by model.

10. Press the ▲ key to save all changes, exit installer

setup mode and return to normal operation.

NOTE: After exiting installer setup mode, change the

setpoint to the desired room temperature.

M18419A

overshooting).

6. Press the ▲ key to display the heat cycle rate of 1,

3, 4, 5, 6, 9, or 12. If the desired cycle rate is displayed, press the ▲ key to exit the installer setup mode. To change the heat cycle rate, press the ▼ key to scroll between 1, 3, 4, 5, 6, 9, and 12. Stop

69-1483—1 6

M14689

CHECKOUT

Heating

1. Slide the SYSTEM switch to Heat and the FAN switch to Auto.

2. Press and hold the ▲ key to raise the temperature setting several degrees above the room temperature. After approximately ten seconds, the heating equipment should start. In conventional systems, the system turns on the fan through the use of a

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T8401C ELECTRONIC THERMOSTATS

Cooling

NOTE: To bypass the 5 minute delay, see optional sys-

tem checkout on page 6.

CAUTION

Low Temperature Hazard. Operating at too low of an outdoor temperature may cause compressor damage.

Do not operate cooling if outdoor temperature is below 50°F (10°C). Refer to equipment manufacturer instructions.

For compressor protection, during power

interruption and on initial startup, the T8401C Electronic Thermostat will go into a 5 minute delay. During this delay the cooling icon, a snowflake , will flash.

Table 4. Thermostat Sequence of Operations.

Fan Selection System Selection Call Energize Display

Auto Off None None None

On Off None G None

Auto Cool None O None

Auto Cool Snowflake Symbol O, G, Y Snowflake Symbol

Auto Heat None B None

Auto Heat Flame symbol B, W* Flame symbol

*If fan operation (fuel) switch is in E position, G terminal is also energized.

1. Slide the SYSTEM switch to Cool and the FAN switch to Auto.

2. Press the ▼ key to lower the temperature setting several degrees below the room temperature. After approximately five minutes, the cooling equipment should start. The fan starts and stops with the cooling equipment.

3. Press the ▲ key to raise the temperature setting above the room temperature. Cooling system should shut down.

Fan

1. Slide the SYSTEM switch to Off and the FAN switch to On. The fan should run continuously.

2. Slide the FAN switch to Auto. In heating, the fan is controlled directly by the heating equipment and may start a few minutes after the heating equipment turns on (on most systems). When using an electric heat thermostat, the fan starts and stops with the heating equipment. In cooling, the fan starts and stops with the cooling equipment.

Consult the instructions provided with The Zone Panel to troubleshoot system problems. Refer to Table 4 for the thermostat’s Sequence of Operations.

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T8401C ELECTRONIC THERMOSTATS

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