Robertshaw 8406 User Manual

DIGITAL
NON-PROGRAMMABLE
THERMOSTAT

8

406

ELECTRIC

E

®

NeW

1 Cool

User's Manual

Quick Start
Installation

Application

The Robertshaw 8406 is a single-stage thermostat designed to control
24 VAC cooling systems.

Features

• Low battery indicator

• Large backlit display

• Adjustable temperature differential: 1°F to 3.0°F (0.5°C to 1.5°C)

• Compressor short cycle protection

• Accuracy within ±1°

• Zone system compatible as a master thermostat

• Permanent memory retention

• Fahrenheit/Celsius display option

• Adjustable from 45°F to 90°F (7°C - 32°C)

• Quick wire terminal block

1

110-1089B

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WARNING:

• Always turn off power at main fuse or circuit breaker panel before
installing, removing, cleaning, or servicing thermostat.

• Read all the information in this manual before installing this thermostat.

• DO NOT CONNECT TO 120 VAC. This is a 24 VAC low-voltage
thermostat. Do not install on voltages higher than 30 VAC.

• All wiring must conform to local and national building and electrical
codes and ordinances.

• Do not short (jumper) across terminals on the gas valve or at the
system control to test installation. This will damage the thermostat
and void the warranty.

• Do not connect ground to any terminal in this unit.

Recycling Thermostat

If this thermostat REPLACES a thermostat that contains mercury,
DO NOT discard the old thermostat in the regular trash. Mercury
is harmful to humans and the environment. For this reason, do
not open, break, or crush the mercury cell. If mercury leaks from
a damaged cell, DO NOT touch or handle mercury with bare
hands. Use protective, non-absorbent gloves to place mercury
into a sealable container. Fill the container with sand or another
absorbent material and seal the container completely.

Return the mercury or mercury products, in a sealed container, to
Invensys Controls Americas or a local recycling center for proper
disposal. If you have any questions, call Robertshaw technical
support at 1-800-445-8299.

Invensys Controls Americas
28C Leigh Fisher Blvd.
El Paso, TX 79906
Attn: Mercury Recycling Center

Step 1: Replacing Existing Thermostat

Wiring Table

Old Terminal New Label Description

M,W,Rh,R5 or 5 Rh Heat transformer, hot side

V or Rc Rc Cool transformer, hot side

Y or Y6 Y1 Cooling control

F or G G Fan control relay

2

!

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1. Turn off power to heating and cooling system.

2. Remove cover from old thermostat to expose wires (Figure 1).

3. Disconnect wires one at a time from existing terminals. Use enclosed
labels to mark existing wires. Refer to cross references in the Wiring Table
if existing wiring does not directly match the labels.

4. Remove existing thermostat base from wall.

Step 2: Installing Model 8406 Thermostat

NOTE: FOR NEW INSTALLATIONS, MOUNT THERMOSTAT ON

INSIDE WALL, FIVE FEET ABOVE THE FLOOR. DO NOT
INSTALL BEHIND A DOOR, IN A CORNER, NEAR AIR
VENTS, IN DIRECT SUNLIGHT, OR NEAR ANY HEAT OR
STEAM GENERATING FIXTURES. INSTALLATION AT THESE
LOCATIONS WILL AFFECT THERMOSTAT OPERATION.

1. Turn power off to the heating and cooling systems.

2. Place OFF-COOL in OFF position (Figure 2).

3. Place AUTO-ON switch into AUTO position (Figure 2).

3

Figure 1

Figure 2

off cool

auto on

°

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off cool

auto on

°

F

4. Remove the cover using a coin or screwdriver (Figure 3). Set aside.

5. Place thermostat against the wall at desired location. Make sure
wires will feed through opening (Figure 4) on base of thermostat.

6. Mark placement of mounting holes (Figure 4). Set base aside.

7. If mounting on drywall, tap plastic anchors into wall.
NOTE: Enclosed plastic anchors do not require a drilled hole
for drywall.

8. If mounting on a surface other than drywall, drill the marked holes
using a 3/16" (5mm) drill bit.

9. Align base with plastic anchors and feed wires through opening.

10. Secure base to wall with supplied screws. NOTE: The thermostat
will mount horizontally on a single gang junction box.

11. Strip end of wires 5/16” (8mm) if needed.

12. Terminal screws are already loose and ready for wire insertion.
Insert wires into terminal strip (Figure 4) matching the label to the
corresponding terminal (see Wiring Diagrams). Tighten screws.

4

Figure 3

Figure 4

Mounting Holes

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auto on

at off cool

he

°

F

N

O

M

set

vac

p

clock

tem

hold

hold

run/set

prog

GOB Y1W1

RH

RC

ELEC GAS

–

°

F

+
–

+

5

♦ Wiring Diagrams

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COOL ONLY

2-WIRE

SINGLE TRANSFORMER

Factory-Installed

Jumper

Transformer

Hot

120 VAC

24 VAC

Cooling
Control

COOL ONLY

3-WIRE

SINGLE TRANSFORMER

Factory-Installed

Jumper

RH

T
H

RC

E
R

Y1

M
O

G

S
T

A

T

Transformer

120 VAC

Hot

24 VAC

Cooling
Control

Fan

Control

RH

T

H

RC

E

R

Y1

M
O

G

S
T

A

T

13. Make sure wire connections are secure.

14. Push excess wire back through opening.

15. Set the Electric/Gas switch to ELEC (Figure 5).

16. Install two AA Energizer

®

brand batteries or equivalent into

battery compartment as shown (Figure 5).

17. Replace thermostat cover by snapping into place.

6

Figure 5

TERMINAL LEGEND - 8406

TERM EQUIPMENT TO CONNECT REQ? TERMINAL FUNCTION

Rh 24VAC hot connection Yes For input of 24VAC hot

side of heat transformer

Rc 24VAC hot connection Yes For input of 24VAC hot

side of cool transformer

Y1 Compressor Connection Yes* Energizes on a call for

cooling

G Indoor fan connection Yes Energizes with Y1 & W1

terminals or with FAN
option switched to the
ON position

Correct battery
placement

ELECTRIC/GAS SWITCH

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–

GOB Y1W1

°

F

RH

RC

ELEC GAS

+
–

+

7

Step 3: Testing the Thermostat

WARNING: DO NOT SHORT (JUMPER) ACROSS TERMINALS OF GAS

VALVE OR SYSTEM CONTROL TO TEST OPERATION. THIS WILL
DAMAGE THE THERMOSTAT AND VOID YOUR WARRANTY.

CAUTION: DO NOT SWITCH SYSTEM TO COOL OR LEAVE IN COOL MODE

IF THE TEMPERATURE IS BELOW 50°F (10°C). THIS CAN
DAMAGE THE AIR CONDITIONING SYSTEM AND CAUSE
PERSONAL INJURY.

1. Place the OFF-COOL switch into the COOL position.
The will be displayed.

2. Press the button until the temperature
setting is at least 3 degrees below the room temper­ature. The air conditioning system should turn on
within a few seconds.

NOTE: ONCE THE THERMOSTAT TURNS OFF WHEN IN THE COOL MODE,

A BUILT IN 5-MINUTE DELAY PREVENTS THE SYSTEM FROM
TURNING ON AGAIN. THIS PROTECTS THE COMPRESSOR. NO
ADDITIONAL TIME DELAY RELAY IS REQUIRED. TO OVERRIDE THE
5-MINUTE DELAY FOR INSTALLATION, PRESS THE RESET BUTTON.

3. Put the OFF-COOL switch into the OFF position.
The air conditioning system should turn off.

4. Put the AUTO-ON switch into the ON
position. The blower fan should turn on.
The display will show a .

5. Put the AUTO-ON switch into the AUTO
position. The blower fan should turn off.

off cool

off cool

!

auto on

auto on

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Step 4: Customizing the Thermostat

♦ Settings

System

Cool: The thermostat controls the cooling.
Off: The heating and cooling systems are off.

Fan

Auto: Equipment controls the fan.
On: The fan operates continuously.

♦ Temperature Differential

The temperature differential is factory set at 1.0°F (.5°C). This means that
whenever the room temperature changes by one degree Fahrenheit
from the temperature setting, the system will turn on. If the system turns
on too often, increase the temperature differential.

♦ Changing Fahrenheit (°F) to Celsius (°C),

the Temperature Differential, and
the Filter Monitor

1. The thermostat is preset to display the
temperature in degrees Fahrenheit (US
models) or degrees Celsius (Canadian
models). The temperature display can be
changed. Press and hold both the

and buttons for three seconds. The display will flash either an F

or C. Release buttons. Press the or button to switch the display.

2. Wait five seconds or press and the display will switch to the
differential setting.

3. The display will read diFF. The tempera­ture differential is factory set at 1.0°F
(0.5°C). Press the or button to adjust
the differential up or down.

4. Wait five seconds or press and the
display will switch to the
filter monitor setting.

5. CHECK FILTER and the length of hours for
the filter monitor will be displayed.

6. Use the or to adjust the filter timer
from 0 (OFF) to 9900 hours. NOTE: The
filter timer is based on equipment run
time. Select the length of time based on
the recommended service interval for
your filter.

7. Press the to return to normal operation.

8

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9

♦ Check Filter Reset

Once the filter timer has expired,
CHECK FILTER will turn on and stay
on. To clear the message and reset
the timer:

1. Press the and buttons and hold
for 3 seconds. CLr will appear in the
time display.

2. Press any key to clear the message.
The display will transition to the
temperature scale display as
described in the previous section.

3. No further input is needed. Within a few seconds, the display will
return to the normal operating mode.

♦ Backlit Display

This thermostat is equipped with a backlight to make night time temper­ature adjustments quick and easy. Press the button to activate the
backlight. The backlight will turn off after about 10 seconds of inactivity.

♦ Reset

To reset the thermostat press the RESET button located above the upper
left corner of the display.

RESET BUTTON

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°

F

RH

GOB Y1W1

RC

ELEC GAS

–

+
–

+

Step 5: Troubleshooting

Symptom Remedy

Thermostat does not turn on system.

Check wiring (see Installation
section).

10

Thermostat turns system on and
off too frequently.

Increase temperature differential
(see Changing the Temperature
Differential section).

Display is blank, flashing or
constant LO BATT.

Replace batteries.

Thermostat does not display
proper room temperature.

Check F/C (Fahrenheit/Celsius)
setting. See Changing Fahrenheit
(F) to Celsius (C).

Note: Although the thermostat has a low battery indicator, replace the

batteries once a year to prevent leakage and to prevent the ther­mostat and heat/cooling system from shutting down due to lack
of battery power in the thermostat.

If problems with thermostat cannot be resolved, call:

Technical Support: [phone]

Monday-Friday 7:30 AM - 5:30 PM CST

For after hours service, a 24-hour automated help line is available.

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11

Two Year Limited Warranty

Invensys Controls Americas warrants to the original contractor installer,
or to the original consumer user, each new Robertshaw
thermostat to be free from defects in materials and workmanship under
normal use and service for a period of two (2) years from date of
purchase. This warranty and our liability does not apply to batteries or
merchandise that has been damaged by misuse, neglect, mishandling,
alterations, improper installation, or use in a way other than in
accordance with Invensys Controls Americas recommendations
and instructions.

Invensys Controls Americas agrees to repair or replace at its option any
thermostat under warranty provided it is returned within the warranty
period, postage prepaid, with proof of the date of purchase. Cost of
thermostat removal or reinstallation is not the responsibility of Invensys
Controls Americas.

Repair or replacement as provided under this warranty is the exclusive
remedy of the consumer. Invensys Controls Americas shall not be liable
for any incidental or consequential damages for breach of any express or
implied warranty on this product, or under any other theory of liability.
Except to the extent prohibited by applicable law, any implied warranty of
merchantability or fitness for a particular purpose on this product is
limited to the duration of this warranty.

Some states do not allow the exclusion or limitation of incidental or
consequential damages, or allow limitations on how long an implied
warranty lasts, so the above limitations or exclusions may not apply to
you. This warranty gives you specific legal rights, and you may also have
other rights which vary from state to state.

For warranty returns, send thermostat, shipping prepaid to:

Invensys Controls Americas

Warranty Claims Department

515 S. Promenade

Corona, CA 92879-1736

©2005 Invensys Controls Americas 110-1089B

Controls Americas

191 E. North Avenue
Carol Stream, Illinois 60188
United States of America

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NOTES

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