Pentax CHRONOTHERM III T8611G User Manual

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TRADELINE

T8611G,R

Chronotherm III

Fuel Saver Thermostats

Application

These thermostats provide energy saving control for a 24
Vac multistage heat pump heating/cooling system as indi­cated in Table 1 and are powered directly from the control
transformer. All models have 5-1-1 programming.

As long as AC power is continuously available to trans­former, the thermostat will be compatible with most control
systems.

The T8611G,R models include SYSTEM and ENRG
SAV LEDs near the top front of the thermostat. The SYS­TEM LED lights when the thermostat is signaling for heating
or air conditioning. The ENGR SAV LED lights during the
LEAVE and SLEEP periods.

TABLE 1—Thermostat Models.

Thermostat Stages Switching LEDs Changeover Terminals Comments See Fig.

T8611G 2 1 EM.HEAT- ON- EM.HT, Auto R, C/X, L, — 4

T8611R 2 1 EM.HEAT- ON- EM.HT., Manual R,C/X,L, — 5

Heat Cool System Fan

HEAT-OFF- AUTO AUX.HT. W
AUTO-COOL B,Y,X2,X

HEAT-OFF- AUTO AUX.HT. W

21EM.HEAT- ON- EM.HT. Manual R,B,X,W

COOL O,B,Y,P

HEAT-OFF- AUTO E,W
COOL H,Y

Installation

WHEN INSTALLING THIS PRODUCT...

1. Read these instructions carefully. Failure to allow
them could damage the product or cause a hazardous condi­tion.

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

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

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

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

The AUX. HT., EM. HT., and CHECK LEDS are located
near the bottom center of the subbase. See Table 1. The AUX.
HT. LED lights whenever the thermostat is calling for
operation of the backup or auxiliary heater. Backup (auxil­iary) heat is more expensive to operate than the heat pump and
typically is used only when the heat pump is unable to handle
the load. The EM. HT. LED lights whenever the thermostat
system switch is in the EM. HT. position. The CHECK LED
lights when something needs to be checked to maintain
efficient operation of the system. Consult heat pump equip­ment literature to determine specific meaning of this LED.

Heat and cool anticipation is fixed in all models; no
adjustment is necessary. Cycle rates are adjustable for auxil­iary heating stage.

,E,G,O,

2

1

,E,W1,G,

2

, Exact 6

2

,G,O, replacement

1

for York

1

model no.
2ET11700224.

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 thermostat and subbase about 5 ft. [1.5m] above the

floor in an area with good air circulation at room temperature.

Do not install the thermostat where it may be affected

J.H. • 3-92 • © Honeywell Inc. 1992 • Form Number 69-0348—1

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 behind the thermostat, such

as an outside wall.

IF REPLACING AN EXISTING THERMOSTAT

Turn off power to thermostat at furnace or heat pump. A

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

IF NEW INSTALLATION

Run a cable to a hole at the selected wall location, and pull

about 3 in. [76 mm] of wire through the opening. Color­coded, 8-gauge thermostat cable with one conductor for each
wiring terminal is recommended. Good service practice
recommends selecting cable with one or two more conduc­tors than the immediate application requires.

MOUNTING SUBBASE

The subbase does not require leveling for proper opera-

tion, but for appearance only.

Remove thermostat from subbase, see Fig. 1.
The subbase mounts directly onto the wall with the screws

included in the package. Use the subbase as a template, and
with a pencil, mark the two mounting screw positions, see
Fig. 2. Use 3/16 in. bit to drill holes for anchors. Gently tap
anchors into holes until they are flush with the wall surface.
Thread wires through the center opening of the subbase. Then
mount the subbase using two screws provided. Gently tighten
screws level top surface of subbase, then securely tighten
screws.

Fig. 1—Removing thermostat from subbase.

Fig. 2—Mounting subbase on wall.

WALL

WIRES THROUGH
WALL OPENING

WALL
ANCHORS
(2)

SUBBASE

MOUNTING
SCREWS (2)

MOUNTING
HOLES

M5175

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 Figs. 4-6 for typical hookups of subbase and
thermostat.

NOTE: Keep all wiring restricted to ribbed area surround-

ing terminals to assure thermostat/subbase contact, see

Fig. 3.

Fig. 3—Keep wiring restricted to ribbed area

surrounding terminals.

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

SYSTEM

EM. HT.

HEAT

OFF

AUTO

COOL

F

A
N

O

N

A

U

T

O

A

U

X

. H

E

A

T

C

H

E

C

K

M5179A

RESTRICT
WIRING TO
THIS AREA

FRONT VIEW OF

TERMINAL AREA

WIRING TO BE BELOW
THIS SURFACE

CROSS-SECTIONAL VIEW OF

TERMINAL AREA

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

TOP SURFACE
OF SUBBASE

M3062

2

Fig. 4—T8611G 2-stage heat/1-stage cool thermostat.

2

POWER
SUPPLY

FAN
SWITCH

HIGH
LIMIT

SYSTEM
SWITCH

EM. HT.

HEAT

OFF

AUTO

COOL

ON

AUTO

HEAT 1

THERMOSTAT
LOGIC
CIRCUIT

1

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

2

DENOTES THERMOSTAT TO SUBBASE INTERCONNECT.

3

POSSIBLE CHECK LED CIRCUITS:

SUBBASE
LOGIC/
CONTROL
CIRCUIT

HIGH
LIMIT

EM. HEAT
LED (RED)

COOL

AUX. HEAT
LED (GRN)

HEAT 2

C.O.

C.O.

CHECK LED
(YELLOW)

R

C/X

L

W2

E

G

O

B

Y

X1

X2

MONITOR

EMERGENCY
HEAT RELAY

FAN RELAY

CHANGEOVER
RELAY (HEAT)

3

1

L1

L2

(HOT)

AUXILIARY
HEAT RELAY

CHANGEOVER
RELAY (COOL)

COMPRESSOR
CONTACTOR

X1

CHECK

FAULT DETECTION

LED

SWITCH

(YELLOW)

X2

SWITCH TO R (POWER) SIDE OF
SYSTEM TRANSFORMER

TO R

TO C/X

X1

CHECK

FAULT DETECTION

LED

SWITCH

(YELLOW)

X2

SWITCH TO C (COMMON) SIDE
OF SYSTEM TRANSFORMER

TO R

TO C/X

X1

CHECK

SWITCHING

LED

DEVICE

(YELLOW)

SWITCH IN SECONDARY OF
SEPARATE TRANSFORMER

24 Vac

X2

L1
(HOT)

L2

1

M 6020

369-0348—1