Honeywell CT8602C User Manual

CT8602C

Professional Fuel Sa ver Thermostat

Application

This thermostat provides energy saving control for a
24 Vac gas, oil, or electric heating or heating/cooling
system with independently controlled fan. System switch
positions include HEAT-OFF-COOL: fan switch positions
include ON-AUTO.

Power is supplied for the device by three AA alkaline
batteries (included in package). This allows the thermostat
to be compatible with all control applications.

Heat and cool anticipation is fixed; no adjustment is
necessary. Cycle rates are adjustable for heating.

The current rating is 1.6A maximum up to 30 Vac.

Recycling Notice

M3375

If this control is replacing a control that contains mer­cury in a sealed tube, do not place your old control in the
trash. Contact your local waste management authority for
instructions regarding recycling and the proper disposal of
your old control.

If you have any questions, call Honeywell Inc. at 1-800­468-1502.

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 the ratings given on the product to make sure
the product is suitable for your application.

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

4. Allow thermostat to warm to room temperature
before operating.

CA UTION

Disconnect power supply to prevent electrical
shock or equipment damage.

Do not install the thermostat where it may be affected by:
— drafts or dead spots behind doors, in corners, or under

cabinets.
— 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.

IF REPLACING AN EXISTING THERMOSTAT

Turn off power to thermostat at furnace or boiler. A two-

transformer system may require turning off two switches or
disconnects. Remove any existing wallplate or subbase
from wall. To avoid miswiring later, label or write down
each wire with the letter or number on the wiring terminal
as the wire is removed.

IF NEW INSTALLATION

Run cable to the hole in the selected wall location, and

pull about 3 in. (76 mm) of wire through the opening.
Color-coded, 18 gauge thermostat cable with at least one
conductor for each wiring terminal is recommended.

MOUNTING WALLPLATE

Remove thermostat from wallplate (Fig. 1).
The wallplate does not require leveling for operation,

but only for appearance. The wallplate mounts directly
onto the wall with the screws included in the package. Use
the wallplate as a template, and with a pencil, mark two
mounting screw positions that best fit the application using
two of the three mounting holes in the wallplate (Fig. 2).
Use 3/16 in. bit to drill holes for anchors. Gently tap
anchors into holes until flush with the wall surface. Thread
wires through the center opening of the wallplate. Then
mount the wallplate using the two screws provided. Gently
tighten screws, level top surface of wallplate, and securely
tighten the screws.

Fig. 1—Removing thermostat from wallplate.

IMPORTANT: Push excess wire back into the hole, and

plug the hole with non hardening caulk, putty or
insulation to prevent drafts from affecting thermo­stat operation.

LOCATION

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

S. M. • Rev. 3-95 • • ©Honeywell Inc. 1995 • Form Number 69-0446—2

M8850

1 69-0446—2

M3375

Fig. 2—Mounting wallplate on wall. Fig. 4—CT8602C heating-only circuit in a

continuous pilot gas system.

WALL
ANCHORS
(2)

WIRES THROUGH
WALL OPENING

USE TWO MOUNTING HOLES THAT

1

BEST FIT APPLICATION.

WALL

WALLPLATE

MOUNTING
HOLES (3)

1

MOUNTING
SCREWS (2)

M2917

WALLPLATE

FACTORY­INSTALLED
JUMPER

G

W

FAN RELAY

GAS

1
L2
L1

(HOT)

1

VALVE

24V

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

RCR

Y

M121A

WIRING

All wiring must comply with local electrical codes and

ordinances.

Disconnect power before wiring to prevent electrical

shock or equipment damage.

The shape of the terminal barrier permits insertion of
straight or conventional wraparound wiring connections.
Either method is acceptable.

Refer to Table 1 and Fig. 4 through 8 for wiring guide­lines.

NOTE: Keep all wiring restricted to ribbed area surrounding

terminals (Fig. 3) to assure thermostat/wallplate contact.

TABLE 1—TERMINAL CROSS REFERENCE.

Old Thermostat

Terminal Marked Function

G or F Fan G
Y or C Cooling Y
W or H Heating W
RC, V, VC or R Power RC
RH, M, VR, 4 Power R

Fig. 3—Keep wiring restricted to ribbed area

surrounding terminals.

FOR STRAIGHT
INSERTION –
STRIP 5/16 in. [8 mm]

FRONT VIEW OF

TERMINAL AREA

WIRING TO BE BELOW
THIS SURFACE

CROSS-SECTIONAL VIEW OF

TERMINAL AREA

New Thermostat

Terminal Marked

FOR WRAPAROUND –
STRIP 7/16 in. [11 mm]

RESTRICT
WIRING TO
THIS AREA

TOP SURFACE
OF SUBBASE

M2927

Fig. 5—CT8602C heating-only circuit in an oil
system.

WALLPLATE

FACTORY­INSTALLED
JUMPER

G

W

L1

HOT

)

(

1

L2

POWER SUPPLY. PROVIDE DISCONNECT MEANS

1

AND OVERLOAD PROTECTION AS REQUIRED.

TT

OIL PRIMARY

RCR

Y

M122

Fig. 6—CT8602C heating/cooling circuit in a
single transformer system with gas heat and
electric cooling or electric heat and electric
cooling, RC and R terminals.

WALLPLATE

FACTORY­INSTALLED
JUMPER

G

W

FAN RELAY

2

HEATING
PRIMARY
CONTROL

24V

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

PRIMARY CONTROL SUCH AS GAS VALVE OR
ELECTRONIC IGNITION MODULE.

L1

HOT

(
L2

1

)

1

2

RCR

COOLING
CONTACTOR

Y

M119

69-0446—2 2

Fig. 7—CT8602C heating/cooling circuit in a two
transformer (one for heating, one for cooling)
system with gas heat and electric cooling, RC
and R terminals. Remove factory-installed R-RC
jumper.

WALLPLATE

Setting and Adjustments

ADJUSTING CYCLE RATE

NOTE: MOST APPLICATIONS DO NOT REQUIRE A

CHANGE IN CYCLE RATE.

1

L1
(HOT)
L2

1

G

W

24V

L1

HOT

)

(
L2

1

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

PRIMARY CONTROL SUCH AS GAS VALVE OR

2

ELECTRONIC IGNITION MODULE.

2

HEATING
PRIMARY
CONTROL

24V

FAN RELAY

RCR

COOLING
CONTACTOR

Y

M118

Fig. 8—CT8602C heating/cooling circuit in an oil
heating and electric cooling system. Heating
transformer is in oil primary, RC and R termi­nals. Remove factory-installed R-RC jumper.

WALLPLATE

RCR

COOLING
CONTACTOR

Y

L2

L1

HOT

(

G

W

1

)

TT

OIL PRIMARY

FAN RELAY

The room air temperature varies slightly from the com­fort temperature setting with the cycling of the furnace or
air conditioner. The equipment cycles off and on as the
room temperature approaches the setpoint.

The cycle rate of this thermostat is set for heating at six
cycles per hour and for cooling at three cycles per hour as
shipped from the factory. The cooling cycle rate cannot be
adjusted. The heating cycle rate can be adjusted by turning
one or both cycle rate adjustment screws located on the
back of the thermostat. See Fig. 9. Back out the screw about
one-half to one turn, or turn in until tight.

ADAPTIVE INTELLIGENT RECOVERY™/
CONVENTIONAL RECOVERY

The thermostat is factory-set for Adaptive Intelligent
Recovery™, but can be converted to conventional recovery
using screw 3A on the back of the thermostat as indicated in
Fig. 9.

With Adaptive Intelligent Recovery™, the room reaches
the comfort temperature at the exact time programmed into
the thermostat. The control temperature increases gradu­ally, and turns the equipment on and off several times to
reach the comfort temperature slowly and on time. There is
no wasted energy associated with rapid temperature changes
and temperature overshoot.

With conventional recovery, program the start time to
be earlier than the desired comfort time. It may require
some trial and error to arrive at the best starting time.

L1

1

HOT

)

(
L2

1

24V

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

Fig. 9—Adjustments.

RECOVERY
SELECTION

ADAPTIVE

INTELLIGENT ™

CONVENTIONAL

SYSTEM
GRAVITY

AIR/WATER

HOT

WATER
GAS/OIL

WARM AIR

ELECTRIC
WARM AIR

OUT 1/2

TO 1 TURN

(FACTORY SETTING)
OUT 1/2

TO 1 TURN

1A

TO 1 TURN

IN

OUT 1/2

TO 1 TURN

IN IN

1B

OUT 1/2

IN

3A

IN

(FACTORY SETTING)

OUT 1/2 TO 1 TURN

3A1A1B

2A 2B

TIME/TEMP

DISPLAY

24 HR IN

12 HR

o

C

o

F

2A 2B

OUT 1/2

TO 1 TURN

M120

IN

OUT 1/2

TO 1 TURN

M8857

NOTE: If you adjust screw 3A for conventional recovery, an

indicator appears in the lower right corner of the thermo-

stat display as a reminder that the Adaptive Intelligent

Recovery™ feature is not active. (Fig. 10).

Fig. 10—Conventional recovery indicator.

SET

PM

TUE

LEAVE

INDICATES
THERMOSTAT IS SET FOR
CONVENTIONAL RECOVERY

PT

M8878

SETTING TIME/TEMPERATURE

The display readout can be converted between a 12 and
24 hour clock or °C and °F using screws 2A and 2B as
indicated in Fig. 9.

INSTALLING BATTERIES

Power is supplied for the thermostat by three AA alka­line batteries. Batteries are included with thermostat. Install
batteries in back of thermostat as shown in Fig. 11. The
display will flash 1:00 PM and room temperature.

When the batteries are going dead, the display will flash
REPL BAT. Set system switch to OFF. Remove the ther­mostat from the wall and install three new AA alkaline
batteries. We recommend Energizer® batteries. Change

3 69-0446—2

batteries within approximately 30 seconds from the time

SET

PRESENT
DAY/TIME

SET

PRESENT
DAY/TIME

DAY

the batteries are removed to prevent program loss and
reprogramming.

IMPORTANT: The low battery warning displays about

two months before the batteries are dead. When the
batteries are dead, the system shuts down. After bat­teries are replaced, thermostat requires reprogram­ming.

Fig. 11—Battery placement.

BATTERY
PLACEMENT
(NOTE CORRECT PLUS

M2083

AND MINUS DIRECTION)

MOUNTING THE THERMOSTAT

Hang the thermostat on the tabs at the top of the base
(Fig. 12a). Swing down and press on lower edge until
thermostat snaps into place (Fig. 12b). Open the cover, and
tighten the captive mounting screws (Fig. 12c).

SETTING DAY AND TIME

Set present day and time. When the thermostat is first
turned on, the display will read 1:00 PM and room tempera­ture. It will go off for a few seconds, then begin to flash on
and off.

Press .

Press TIME or to set the current time.

AHEAD

BACK

Press .

Press to set the current day. Each press of the
DAY KEY advances the display one day.

If the display does not come on:

• Check mounting of thermostat to wallplate. If loose or
misaligned, remove thermostat and reinstall on
wallplate, making sure it is firmly attached.

• Check to see that all the batteries are good and in­stalled correctly.

Fig. 12—Mounting thermostat on wallplate.

A.

C.

RUN

PROGRAM

SET

PRESENT

DAY

DAY/TIME

HOLD

SET

TEMP

HEAT/COOL

B.

PM

MON

RETURN

HEAT ON

PM

MON

HEAT ON

RETURN

TEMPERATURE

PRESENT
SETTING

WAKE

SLEEP

RETURN

AHEAD

BACK

TIME

LEAVE

WARMER

COOLER

PERIOD

CHANGE
TO LAST
PERIOD

SKIP
NEXT

M8849

69-0446—2 4

Checkout

HEATING

Move the system switch to HEAT and the fan switch to

AUTO. Press WARMER key until the setting is about 10°F
(6°C) above room temperature. Heating should start and
the fan should run after a short delay. Press COOLER key
until the setting is about 10°F (6°C) below room tempera­ture. The heating equipment should shut off.

COOLING

CA UTION

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

NOTE: When cooling setting is changed, thermostat will

wait up to five minutes before turning on the air condi­tioner. This delay protects the compressor.

Move the system switch to COOL and the fan switch to

AUTO. Press COOLER key until the setting is about 10°F
(6°C) below room temperature. The cooling equipment and
fan should start. Press WARMER key until the setting is
about 10°F (6°C) above room temperature. The cooling
equipment and fan should stop.

FAN

Move the system switch to OFF, and the fan switch to
ON. The fan should run continuously. When the fan switch
is in the AUTO position, the fan cycles with the heating or
cooling system.

INSTALLER SELF-TEST (Optional)

Perform the following test as a check of all thermostat
functions. If thermostat does not respond as indicated,

replace thermostat.

1. Press AHEAD and BACK keys at the same time.
while holding down keys, all segments of the display should
be on (see Fig. 13).

Fig. 13—All segments on display.

REPL

AM

BAT

PM

SUN MON TUE WED THU FRI SAT COOL ON HEAT ON
WAKE LEAVE RETURN SLEEP TEMPORARY

2. Set system switch to OFF. Press AHEAD and BACK
and PRESENT SETTING keys at the same time to enter
self-test.

3. Press each key as listed on next page, and look for
response listed as key is held down and released.

SET
PT

M8856

5 69-0446—2

System Press

RETURN

LEAVE

Switch

Position

OFF 03 Blank

This

Key

CHANGE

TO LAST

PERIOD

SKIP

NEXT

PERIOD

PRESENT

SETTING

Look For This Response

Key

Down

Key
Released

07 Blank
15 Blank

First
Digit

Cycle Rate Setting

(cph at 50% On Time)

0 or 1 1
2 or 3 3
4 or 5 9
6 or 7 6

COOL (with
fan in

PRESENT

SETTING

15 Cooling and fan

on.

AUTO)

PRESENT

SETTING

OFF 06 Blank

WARMER

COOLER

AHEAD

BACK

15 Colling and fan

off.

02 Blank
05 Blank
04 Blank
01 Blank
00 Blank

(CHECK

WAKE

12 See note A
EACH
POSITION)

OFF 08 Blank

SLEEP

DAY

13 Microprocessor

mask no. and
revision no.

SET

HEAT/COOL

SET

PRESENT
DAY/TIME

HEAT 14 Heating on.

1

▲▲

OFF 10 Blank

SET

PRESENT
DAY/TIME

SET

PRESENT
DAY/TIME

HOLD

TEMP

RUN

PROGRAM

09 Blank

14 Blank

14 Heating off.

11 Normal operating

display.

END SELF-TEST

1 For electric heat fan operation, the fan operates with

▲▲

the heating system when the fan switch is in AUTO.

A HEAT displayed when system switch is in HEAT,

COOL when in COOL, neither when in OFF. A four­digit code is displayed with each digit explained as
follows.

Second

Digit

Clock

(hr) Degrees

Recovery

Setting

0 12 F Conventional
1 12 C Conventional
2 12 F Adaptive Intelligent

Recovery™

3 12 C Adaptive Intelligent

Recovery™
4 24 F Conventional
5 24 C Conventional
6 24 F Adaptive Intelligent

Recovery™
7 24 C Adaptive Intelligent

Recovery™

▼▼

▼▼

Third Digit System Switch Position

0 OFF
2 COOL
4 HEAT

Fourth Digit System Switch Position

0 Any position
1 HEAT, OFF, or COOL
4 Any position
5 HEAT, OFF, or COOL

Allow thermostat to reach room temperature before pro­gramming. Then refer to owner’s manual for programming
instructions and homeowner troubleshooting.

This equipment is a Class B digital apparatus which complies with Canadian Radio Interference Regulations, CRC c. 1374.

Home and Building Control Home and Building Control Helping You Control Your World

Honeywell Inc. Honeywell Limited—Honeywell Limitée
1985 Douglas Drive North 740 Ellesmere Road
Golden Valley, MN 55422 Scarborough, Ontario

M1P 2V9

69-0446—2 6

Printed in U.S.A.

QUALITY IS KEY