background image

Terminal Designations

This thermostat is shipped from the factory to operate a conventional heating

and cooling system. This thermostat may also be configured for a heat pump 

system. See the “heat pump” configuration step on page 17 of this manual to 

configure the thermostat for heat pump applications.

Wiring

Terminal

2 Heat 2 Cool

Conventional 

System

2 Heat 2 Cool

Heat Pump 

System

 3 Heat 2 Cool

Heat Pump 

System

RC

RH

C

B

O

G

W/E

Y

Y2

W2

Transformer power

(cooling)

Transformer power

(heating)

Transformer common

Energized in heating

Energized in cooling

Fan relay

First stage of heat

First stage of cool

Second stage of cool

Second stage of heat

Transformer power

(cooling)

Transformer power

(heating)

Transformer common

Heat pump changeover 

valve energized in heating

Fan relay

First stage of 

emergency heat

First stage of heat & cool

Second stage of cool

Auxiliary heat relay,

second stage of heat

Heat pump changeover 

valve energized in cooling

Transformer power

(cooling)

Transformer power

(heating)

Transformer common

Heat pump changeover 

valve energized in heating

Fan relay

First stage of 

emergency heat

First stage of heat & cool

Second stage of cool 

& second stage of heat

Auxiliary heat relay,

third stage of heat

Heat pump changeover 

valve energized in cooling

Wiring

Caution: 

Electrical Hazard

All components of the control 

system and the thermostat 

installation must conform to 

Class II circuits per the NEC Code.

Warning:

Do not overtighten terminal 

block screws, as this can 

damage the terminal block.  

A damaged terminal block 

can keep the thermostat 

from fitting on the subbase 

correctly or cause system 

operation issues.

Installation Tip

Max Torque = 6in-lbs.

Wiring

If you are replacing a thermostat, 

make note of the terminal 

connections on the thermostat that 

is being replaced.  In some cases 

the wiring connections will not be 

color coded. For example, the 

green wire may not be connected 

to the 

G

 terminal.

Loosen the terminal block screws. 

Insert wires then retighten the 

terminal block screws.

Place nonflammable insulation into 

the wall opening to prevent drafts.

1.

2.

3.

Wiring Tips

C Terminal

The C (common wire) terminal does 

not have to be connected when the 

thermostat is powered by batteries.

Wire Specifications

Use shielded or non-shielded 18-22 

gauge thermostat wire.

Failure to disconnect the power 

before beginning to install this 

product can cause electrical shock 

or equipment damage.

Note:

In many heat pump systems with 

no emergency heat relay, a jumper 

can be installed between 

E

 and 

W2

 to turn thermostat into a single 

stage control for Emergency Heat 

Operation.

Thermostat Quick Reference

The low battery indicator is displayed when the AA battery power is low. If the user 

fails to replace the battery within 21 days, the screen will only show the low battery 

indicator but maintain all functionality.  If the user fails to replace the batteries after 

an additional 21 days (days 22-42 since first “low battery” display) the setpoints will 

change to 55˚F (Heating) and 85˚F (Cooling). If the user adjusts the setpoint away from 

either of these, it will hold for 4 hours then return to either 55˚F or 85˚F.  After day 63 

the batteries must be replaced immediately to avoid freezing or overheating because 

the thermostat will shut the unit off until the batteries are changed.

Important

Indicates the current room temperature
Time and day of the week

Staging Indicators:

 +1 will appear in the display when second stage of 

heat or cool is on. +2 will appear for the third stage of heat.

Setpoint:

 Displays the user selectable setpoint temperature.

Hold:

 is displayed when the thermostat program is permanently overridden.

System Operation Indicators:

If these or the Fan indicator are flashing, it means that the system is in a 

delay of some type (compressor delay, cooling fan delay, staging delay).

Low Battery Indicator: 

Replace batterieswhen this indicator is shown.

Program Menu Options: 

Show different options during programming.

Program Time Periods - Residential: 

Uses 4 time periods - WAKE, RETURN, 

LEAVE & SLEEP. 

Commercial:

 Uses 2 or 4 time periods that appear in the text 

field - Occupied & Unoccupied.

Getting to know your thermostat

Thermostat Quick Reference

Battery Installation

Battery installation is recommended even if the thermostat is 

hardwired (C terminal connected).  When the thermostat is hardwired 

and batteries are installed, the thermostat will activate a compressor 

delay of 5 minutes when it detects a power outage from the hardwired 

power supply.

Important:

High quality alkaline batteries are recommended. 

Rechargeable batteries or low quality batteries 

do not guarantee a 1-year life span.

Insert 2 AA Alkaline batteries 

(included). High quality alkaline 

batteries are recommended.

Simple operating instructions

are found on the back of the 

battery door.

To release battery cover press finger bevel 

on the left side and lift the cover to access 

batteries.

Содержание EWT-855

Страница 1: ...to a flat wall 2 Use screws provided 3 Drywall anchors should be flush with the wall 4 Wires should be pushed into the wall Installation Tips The thermostat should be installed approximately 4 to 5 feet above the floor Select an area with average temperature and good air circulation Close to hot or cold air ducts That are in direct sunlight With an outside wall behind the thermostat In areas that ...

Страница 2: ... to install this product can cause electrical shock or equipment damage Note In many heat pump systems with no emergency heat relay a jumper can be installed between E and W2 to turn thermostat into a single stage control for Emergency Heat Operation Thermostat Quick Reference The low battery indicator is displayed when the AA battery power is low If the user fails to replace the battery within 21...

Страница 3: ...rmer Typical2H 2CSystem 2Transformer Typical3H 2Cor2H 1CHeatPumpSystem TypicalHeat OnlySystem TypicalHeatOnlySystemWithFan TypicalCool OnlySystem HEAT RELAY RC RH Y C W E G C R L2 L1 HOT FAN RELAY HEAT RELAY RC RH Y C W E G C R L2 L1 HOT FAN RELAY COMPRESSOR RELAY C R L2 L1 HOT RC RH Y C G Power supply Factory installed jumper Remove only when installing on 2 transformer systems Use either O or B ...

Страница 4: ...You can adjust the filter change reminder from OFF to 2000 hours of runtime in 50 hour increments Tech Setup Steps Room Temperature Calibration 0 F This feature allows the installer to select the minimum run time for the compressor For example a setting of 4 will force the compressor to run for at least 4 minutes every time the compressor turns on regardless of the room temperature You can set the...

Страница 5: ...t This feature allows you to display temperatures in either Fahrenheit or Celsius F or C F F for Fahrenheit C for Celsius You can select either a 12 or 24 hour clock setting 12 or 24 Hour Clock Select GAS for systems that control the fan during a call for heat Select ELEC to have the thermostat control the fan during a call for heat Fan Operation 90 78 12H 12 HOURCLOCK GAS ELE Cooling Temperature ...

Страница 6: ...th the FAN key 5 Press NEXT 6 The setpoint temperature is flashing Use the or key to make your setpoint selection for that day s WAKE OCC1 period 7 Press NEXT 8 Repeat steps 4 through 7 for that day s LEAVE UNOCC1 time period for that day s RETURN OCC2 time period and for that day s SLEEP UNOCC2 time period To customize your 7 day 4 time period Program schedule follow these steps Monday Repeat ste...

Страница 7: ...tpoint and can be adjusted using the or keys To Return To Program Press the RUN SCHED key at the bottom of the screen to exit temporary and permanent holds Temporary Permanent Hold Feature Custom Program Day of the Week Events Time Setpoint Temperature HEAT Setpoint Temperature COOL Weekday Saturday Sunday Wake OCC1 Leave UNOCC1 Return OCC2 Sleep UNOCC2 Wake OCC1 Leave UNOCC1 Return OCC2 Sleep UNO...

Страница 8: ...on condensing maximum Dimensions of thermostat 4 7 W x 4 3 H x 0 9 D Specifications Features If the filter change reminder is enabled you will see a reminder in the display when your air filter needs changed The reminder will be shown in the display after your system has run long enough to require an air filter change Resetting The Filter Change Reminder When the reminder is displayed you should c...

Отзывы: