Honeywell T8112C, T8112D User Manual

T8112C,D Electronic

Programmable Thermostats

INSTALLATION INSTRUCTIONS

APPLICATION

The T8112C,D thermostats provide electronic programmable control for 24 to 30 Vac heating and cooling systems.

RECYCLING NOTICE

If this control is replacing a control that contains mercury in a sealed tube, do

control in the trash. Contact your local waste management authority

for instructions regarding recycling and the proper disposal of the old thermostat.

not

place your old

INSTALLATION

When Installing this Product…

1. Read these instructions carefully. Failure to follow them could 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

1. Disconnect power supply to prevent electrical shock or equipment damage.

2. After wiring is complete, push excess wire back into the hole and plug hole with nonhardening caulk, putty or insulation to prevent drafts from affecting thermostat operation.

Location

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

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.

Mounting Plate Installation

Position mounting plate on the wall. Use a level to make sure mounting plate is level. Use a pencil to mark the two mounting holes. See Fig. 1.

WALL ANCHORS (2)

WIRES THROUGH WALL OPENING

WALL

MOUNTING PLATE

MOUNTING SCREWS (2)

Fig. 1. Mounting plate installation.

M1718

X-XX UL

69-0917-2

T8112C,D ELECTRONIC PROGRAMMABLE THERMOSTATS

1. Remove mounting plate from the wall, and drill 3/16 inch holes in wall (if drywall) as marked. For firmer material such as plaster or wood, drill 7/32 inch holes. Gently tap anchors (provided) into drilled holes until flush with the wall.

2. Reposition mounting plate over holes, pulling wires through wiring opening. Loosely insert two mounting screws into holes.

3. Level for appearance only; the thermostat will function properly even when not level. Tighten mounting screws. See Fig. 2.

LEVEL

M1714A

Fig. 2. Leveling mounting plate.

Adjust Fan Operation Switch, as Required

The Thermostat fan operation switch, labeled FUEL SWITCH is factory set in the F position. See Fig. 4. This is the correct setting for most systems. If your system is an electric heat system, set the switch to E. The E setting allows the fan to turn on immediately with the heating or cooling in a system where the G terminal is connected.

Adjust System On-time, as Required

The system on-time is factory-set for a warm air, gas or oil heating system. If you are installing it on another type of system, the system on-time must be adjusted accordingly by setting screws A and B on the back of the thermostat. Use the heating system table shown in Fig. 3 as a guide. The system on-time should be optimized according to the type of system to minimize room temperature swings. Setting the screw means turning the screw approximately 360° or one complete turn. Setting the screw in means tightening the screw completely down.

In the event that you want longer furnace on-time, readjust the screws A and B as follows:

• Warm Air Furnace—set at the Hot Water setting (A— out one turn, B—in).

• Electric Furnace—Leave at the Warm Air Furnace setting (A—in, B—in).

NOTE: This thermostat does not have a setting for

steam/gravity air. Cycles would not be long enough for accurate temperature control.

out one turn

IMPORTANT

When using a high efficiency furnace such as a 90 percent or greater AFUE (Average Fuel Utilization Efficiency) unit, adjust screw A out one turn and screw B in.

THERMOSTAT BACK

FOR HIGH EFFICIENCY FURNACE (90%+ AFUE) ADJUST:

SCREW A–OUT 1 TURN SCREW B–IN FUEL SWITCH – F POSITION

A C

B D

FUEL SWITCH F

ADJUST SCREWS THROUGH HOLES TO SELECT OPERATION DESIRED

WARM AIR FURNACE

HOT WATER BOILER

ELECTRIC FURNACE

HEATING SYSTEM

A–IN

A–OUT 1 TURN

A–IN

W Y G

B–IN

B–OUT 1 TURN

FUEL SWITCH

POSITION

M3669

Fig. 3. Back view of thermostat.

Wiring Thermostat

All wiring must comply with local electrical codes and ordinances. Ref er to Fig. 4 through 7 for typical hookups. A letter code is located near each terminal for identification. See Table 1 f or terminal cross referencing inf ormation.

CAUTION

Disconnect power before wiring to prevent electrical shock or equipment damage.

1. Connect the system wires to the thermostat. See Fig. 8. A letter code is located near each terminal for identification.

NOTE: Hold the thermostat as shown in Fig. 9 to

minimize need for wire extenders.

2. Securely tighten each terminal screw.

3. Push excess wire back into the hole.

4. Plug hole with nonflammable insulation to prevent

drafts from affecting the thermostat.

Table 1. Typical Wire Colors and Functions

Thermostat

Terminal

G Green Fan

Y Yellow Cooling

W White Heating

Rc Blue Air Cond. Power

R Red Furnace Power

Wire colors are typical; verify at heating/cooling equipment connection.

Connect to

Wire Color

Function

69-0917—2

T8112C,D ELECTRONIC PROGRAMMABLE THERMOSTATS

W Y G

B D

A C

3-WIRE COOL-ONLY (JUMPER INTACT)

L1 (HOT)

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

JUMPER

M848A

COOLING CONTACTOR COIL

FAN RELAY

2-WIRE HEAT-ONLY (JUMPER INTACT)

A C

B D

W Y G

HEATING RELAY OR VALVE COIL

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

Fig. 4. Typical hookup in two wire lead

only (jumper intact) application.

L1 (HOT)

4-WIRE HEAT/COOL (JUMPER INTACT)

A C

B D

W Y G

HEATING RELAY OR VALVE COIL

COOLING CONTACTOR COIL

FAN RELAY

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

Fig. 5. Typical hookup in four wire heat

and cool (jumper intact) application.

5-WIRE HEAT/COOL (JUMPER REMOVED)

A C

B D

JUMPER

HEATING RELAY OR

M1709B

JUMPER

L1 (HOT)

M1710B

VALVE COIL

COOLING

1 1

L1 (HOT)

Fig. 6. Typical hookup in five wire heat

and cool (jumper removed) application.

CONTACTOR COIL

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

FAN RELAY

W Y G

L1 (HOT)

M1711B

Fig. 7. Typical hookup in three wire cool

only (jumper intact) application.

69-0917—2

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