residential

THERMOSTAT

900

Digital

Thermostat

up to 3-heat

HEAT

COOL

HEAT

PUMP with HUMIDITY

CONTROL

Control up to 3 Heat &

2 Cool Stages

3 Configurable Outputs

Adjustable 2nd & 3rd Stage

Timers & Deadbands

Backlit Display & Button

Legends

Aux Heat Indicator

Dry Contact Equipped

Outdoor Sensor Ready with

High/Low Readouts for the Day

Equipped with Optional Humidity

Module: Controls Humidification,

Dehumidification and Reheat

Programmable Output

Accepts EZ Programmer

Accepts Optional IR Remote Control

Accepts Comfort Call

Phone Control Accessory

Use with most Air Conditioning & Heating Systems including: 1 or 2 Stage

Electric Cooling & 3 Stage Gas Heating, Heat Pump, Electric or Hydronic Heat.

INSTALLATION

INSTRUCTIONS

Venstar Inc. 08/07

CAUTION

Follow the Installation Instructions before proceeding.

Set the thermostat mode to “OFF” prior to changing settings in setup or restoring Factory Defaults.

CAUTION

NEVER PUT MORE THAN ONE

JUMPER ON THE SAME MISC

JUMPER BLOCK!

THIS MAY DAMAGE YOUR

THERMOSTAT AND VOID

YOUR WARRANTY.

MISC3

OK

MISC3

NOTE: Due to variations in environmental conditions, it is not always possible to achieve the desired humidification or dehumidification setpoint.

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

4Z95

Thermostat T1900

F C

Tested to Comply with FCC Standards

FOR HOME OR OFFICE USE

Page i

Table of Contents

Preparation

Remove & Replace the

Old Thermostat

Configuring the MISC

Outputs

Wire Connections

Wiring Diagrams

Test Operation

Calibrating the

Thermostat Sensors

TroubleShooting

5

6

7

8

1

2

3

4

Page iii

SECTION 1

Preparation

1

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Proper installation of the thermostat will be accomplished by following these step by step instructions. If you are unsure about any of these steps, call a qualified technician for assistance.

Assemble tools

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Flat Blade

Screwdriver

Wire cutter

& Stripper

Make sure your Heater/Air Conditioner is working properly before beginning installation of the thermostat.

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Carefully unpack the thermostat. Save the screws, bracket, and instructions.

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Turn off the power to the Heating/Air Conditioning system at the main fuse panel. Most residential systems have a separate breaker for disconnecting power to the furnace.

Page 1.1

SECTION 2

Remove & Replace the Old Thermostat

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Remove the cover of the old thermostat.

If it does not come off easily check for screws.

2

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Loosen the screws holding the thermostat base or subbase to the wall, and lift away.

Disconnect the wires from the old thermostat.

Tape the ends of the wires as you disconnect them, and mark them with the letter of the terminal for easy reconnection to the new thermostat.

Keep the old thermostat for reference purposes, until your new thermostat is functioning properly.

Page 2.1

SECTION 3

Configuring the MISC Outputs

3

Section 3 Contents:

Configuring the Jumpers........3.2

Explanation of Jumper

Settings..................................3.3

Page 3.1

Configuring the Jumpers

For additional flexibility, your thermostat has three configurable outputs. These outputs are designed to have different functions

3 depending on how the jumpers are set (below).

Each output, labeled MISC1, MISC2, and MISC3 may be set for one of the five choices available.

In the diagram below, the MISC3 jumper has been set for HUM

(humidification) operation, the MISC2 jumper has been set for DEHUM

(dehumidification) operation, and the MISC1 jumper has been set for

PROG (programmable) operation.

W3

PROG

HUM

DEHUM

W1

Y1

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

G

MISC2

CK1

CKGND

R

C

INSTALL HUMIDITY

MODULE WITH SENSING

ELEMENT OUTWARD

ELEC

GAS

HP

GAS

B

O

W2

MISC1

RS2

MISC3

RS+5

Rs1

RSGND

W3

PROG

HUM

DEHUM

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

CAUTION

NEVER PUT MORE THAN

ONE JUMPER ON THE SAME

MISC JUMPER BLOCK!

DOING SO MAY DAMAGE

YOUR THERMOSTAT AND

VOID THE WARRANTY.

Page 3.2

MISC3

OK

MISC3

Explanation of Jumper Settings

3

W3 JUMPER SETTING

If the jumper for MISC1, MISC2, or MISC3 is set to W3, the corresponding MISC screw terminal on the backplate will control a third stage of heat.

W3 MULTI-STAGE OPERATION EXPLAINED - SECTION 14 of the Owner’s

Manual

The 3rd Stage of Heat is turned on when:

(A) The 1st and 2nd stages have been on for the time required (steps 27

and 28, page 14.6). It is adjustable from 0-60 minutes and the default

is two minutes.

(B) The temperature from the setpoint is equal to or greater than: the set-

point plus the 1st stage deadband (step #24, 14.5), plus the 2nd stage

deadband (step #25, 14.5) plus the 3rd stage deadband (step #26,

14.5). This 3rd stage deadband is adjustable from 0-10 degrees and

the default is two degrees.

Deadband db 3

(adj. 0-10 )

Heating

Deadband db 2

(adj. 0-10 )

Deadband db 1

(adj. 1-6 )

Deadband db 1

(adj. 1-6 )

Cooling

Deadband db 2

(adj. 0-10 )

3rd Stage turn on

2nd Stage turn on

1st Stage turn on

DECREASE

Heat

Setpoint

Cool

Setpoint

TEMPERATURE INCREASE

1st Stage turn on

2nd Stage turn on

PROG JUMPER SETTING

If the jumper for MISC1, MISC2, or MISC3 is set to PROG, the corresponding MISC screw terminal on the backplate will control a pilot relay or other accessory.

PROGRAMMABLE OUTPUT - SECTION 15 of the Owner’s Manual

This jumper setting allows the MISC outputs to control a pilot relay by time, temperature, or a signal from the Internet/Phone. The following are three possible scenarios:

By Time: A device that requires a start and stop time. An example

of this would be an exterior lighting system that needed to be

energized every day between the hours of 8pm and 1am.

By Temperature: An exhaust fan that needs to energize whenever

the temperature from RS2 rises above 90 degrees F.

By Remote: Remotely arming a security system through the web or phone.

Page 3.3

Explanation of Jumper Settings

(continued)

HUM JUMPER SETTING

If the jumper for MISC1, MISC2, or MISC3 is set to HUM, the corresponding MISC screw terminal on the backplate will control a humidification system.

HUMIDIFICATION OPERATION - SECTION 9 of the Owner’s Manual

3

If your HVAC unit is equipped with a humidification system the thermostat will provide power to the MISC1, MISC2, or MISC3 terminal of the thermostat when the humidity in the home falls below the humidity setpoint you have chosen.

The value for this setpoint ranges from 0% to 60%. If no humidity is desired or if a humidification system has not been installed, set the value to OFF.

DEHUM JUMPER SETTING

If the jumper for MISC1, MISC2, or MISC3 is set to DEHUM, terminal on the backplate will be connected to the dehumidification terminal of a furnace board.

NOTE: Not all furnaces have a dehumidification terminal.

the corresponding MISC screw

DEHUMIDIFICATION OPERATION - SECTION 10 of the Owner’s Manual

If your HVAC unit is equipped with a dehumidification system the thermostat will operate in one of two ways.

1) Normally Closed (NC): The thermostat will de-energize the MISC1, MISC2,

or MISC3 terminal of the thermostat (this MISC terminal is connected to the

DEHUM terminal on your furnace) to allow the fan to run in low speed when

the humidity in the home is above the dehumidify setpoint you have chosen

and there is a call for 1st stage cooling.

2) Normally Open (NO): The thermostat will energize the MISC1, MISC2, or

MISC3 terminal of the thermostat (this MISC terminal is connected to the

DEHUM terminal on your furnace) to allow the fan to run in low speed when

the humidity in the home is above the dehumidify setpoint you have chosen

and there is a call for 1st stage cooling.

Page 3.4

Explanation of Jumper Settings

(continued)

3

Y2 JUMPER SETTING

If the jumper for MISC1 is set to Y2 the will control a second stage of cooling.

MISC1 screw terminal on the backplate

Y2 OPERATION - SECTION 14 of the Owner’s Manual

Control up to two Cool stages.

The 2nd Stage of heat or cool is turned on when:

(A) The 1st Stage has been on for the time required (step #27,

page 14.6). It is adjustable from 0-60 minutes and the default

is two minutes.

And

(B) The temperature spread from the setpoint is equal to or greater

than: the setpoint plus the deadband (step #24, page 14.5), plus

the 2nd deadband (step #25, page 14.5). This 2nd deadband is

adjustable from 0-10 degrees and the default is two degrees.

Deadband db 1

(adj. 1-6 )

Cooling

Deadband db 2

(adj. 0-10 )

Cool

Setpoint

1st Stage turn on

TEMPERATURE INCREASE

2nd Stage turn on

Page 3.5

SECTION 4

Wire Connections

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If the terminal designations on your old thermostat do not match those on the new thermostat, refer to the chart below, or the wiring diagrams 4 that follow.

Wire from the old thermostat terminal marked

G or F

Y1, Y or C

W1, W or H

Rh, R, M, Vr, A

C

O/B

W2

MISC1

MISC2

MISC3

RS+5

RS1

RSGND

RS2

CK1

CKGND

Function

Fan

Cooling

Heating

Power

Common

Rev. Valve

2nd Stage Heat

Configurable Output #1

Configurable Output #2

Configurable Output #3

Remote Sensor +5vdc

Remote Sensor Signal

Remote Sensor Ground

Remote Sensor Signal #2

Dry Contact Switch 1

Dry Contact Switch 2

Install on the new thermostat connector marked

G

Y1

W1/O/B

R

C

W1/O/B*

W2

MISC1

MISC2

MISC3

RS+5**

RS1**

RSGND**

RS2**

CK1

CKGND

* O/B is used if your system is a Heat Pump.

** For instructions on connecting these terminals see page 16.2

of the Owner’s Manual. Page 4.1

SECTION 5

Sample Wiring Diagrams

Section 5 Contents:

5

HVAC Equipment Wiring............5.2

MISC1, MISC2, and MISC3

Wiring........................................5.6

Remote Sensor, Outdoor Sensor

and CK1-CK2 wiring for the

Time Clock................................5.8

Page 5.1

6 Wire, 1 Stage Cooling, 1 Stage Heat

Residential & Commercial 1 Stage Cooling, with 1st stage Gas Heat

OR Commercial Heat Pump 1 Stage Cooling with 2 Stage Heat

5

W2

MISC1

RS2

MISC3

RS+5

RS1

RSGND

W1/O/B

Y1

G

MISC2

CK1

CKGND

R

C

ELEC

GAS

HP

GAS

B

O

W3

PROG

HUM

DEHUM

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

W1

Y1

G

MISC2

CK1

CKGND

R

C

INSTALL HUMIDITY

MODULE WITH SENSING

ELEMENT OUTWARD

ELEC

GAS

HP

GAS

B

O

W2

MISC1

RS2

MISC3

RS+5

Rs1

RSGND

6 Conductor 18 gauge unshielded cable from the thermostat to the equipment.

24 vac common

24 vac return fan relay compressor relay

1st stage heat circuit

2nd stage heat circuit

Page 5.2

6 Wire, 1 Stage Cooling, 1 Stage Heat

Residential & Commercial 1 Stage Cooling, with 1st stage Electric Heat

5

W2

MISC1

RS2

MISC3

RS+5

RS1

RSGND

W1/O/B

Y1

G

MISC2

CK1

CKGND

R

C

ELEC

GAS

HP

GAS

B

O

24 vac common

24 vac return fan relay compressor relay

1st stage heat circuit

2nd stage heat circuit

W3

PROG

HUM

DEHUM

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

W1

Y1

G

MISC2

CK1

CKGND

R

C

INSTALL HUMIDITY

MODULE WITH SENSING

ELEMENT OUTWARD

ELEC

GAS

HP

GAS

B

O

W2

MISC1

RS2

MISC3

RS+5

Rs1

RSGND

6 Conductor 18 gauge unshielded cable from the thermostat to the equipment.

Page 5.3

6 Wire, 1 Stage Cooling, 2 Stage Heat

Residential Heat Pump with O Reversing

Valve 1 Stage Cooling, with 2 stage Heat

W2

MISC1

RS2

MISC3

RS+5

RS1

RSGND

W1/O/B

Y1

G

MISC2

CK1

CKGND

R

C

ELEC

GAS

HP

GAS

B

O

W3

PROG

HUM

DEHUM

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

W1

Y1

G

MISC2

CK1

CKGND

R

C

INSTALL HUMIDITY

MODULE WITH SENSING

ELEMENT OUTWARD

ELEC

GAS

HP

GAS

B

O

W2

MISC1

RS2

MISC3

RS+5

Rs1

RSGND

6 Conductor 18 gauge unshielded cable from the thermostat to the equipment.

24 vac common

24 vac return

Fan Relay

Compressor Relay

Reversing Valve

2nd stage heat circuit

Page 5.4

5

6 Wire, 1 Stage Cooling, 2 Stage Heat

Residential Heat Pump with b Reversing

Valve 1 Stage Cooling, with 2 stage Heat

5

W2

MISC1

RS2

MISC3

RS+5

RS1

RSGND

W1/O/B

Y1

G

MISC2

CK1

CKGND

R

C

ELEC

GAS

HP

GAS

B

O

24 vac common

24 vac return

Fan Relay

Compressor Relay

Reversing Valve

2nd stage heat circuit

W3

PROG

HUM

DEHUM

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

W1

Y1

G

MISC2

CK1

CKGND

R

C

INSTALL HUMIDITY

MODULE WITH SENSING

ELEMENT OUTWARD

ELEC

GAS

HP

GAS

B

O

W2

MISC1

RS2

MISC3

RS+5

Rs1

RSGND

6 Conductor 18 gauge unshielded cable from the thermostat to the equipment.

Page 5.5

Adding a 2nd Stage of Cooling (MISC1), Sprinkler System (MISC2), and 3rd Stage of Heating or Dual Fuel Applications (MISC3)

5

W2

MISC1

RS2

MISC3

RS+5

RS1

RSGND

W1/O/B

Y1

G

MISC2

CK1

CKGND

R

C

W3

PROG

HUM

DEHUM

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

Sprinkler System

W3

PROG

HUM

DEHUM

W1

Y1

G

MISC2

MISC3 MISC2

Y2

MISC1 (MISC1

ONLY)

CK1

CKGND

R

C

INSTALL HUMIDITY

MODULE WITH SENSING

ELEMENT OUTWARD

ELEC

GAS

HP

GAS

B

O

W2

MISC1

RS2

MISC3

RS+5

Rs1

RSGND

3rd Stage Heat or Dual Fuel

2nd Stage Cooling

Page 5.6

Adding a Humidification System (MISC1) and Dehumidification System (MISC2)

5

W2

MISC1

RS2

MISC3

RS+5

RS1

RSGND

W1/O/B

Y1

G

MISC2

CK1

CKGND

R

C

W3

PROG

HUM

DEHUM

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

W3

PROG

HUM

DEHUM

MISC3 MISC2 MISC1

Y2

(MISC1

ONLY)

W1

Y1

G

MISC2

CK1

CKGND

R

C

INSTALL HUMIDITY

MODULE WITH SENSING

ELEMENT OUTWARD

ELEC

GAS

HP

GAS

B

O

W2

MISC1

RS2

MISC3

RS+5

Rs1

RSGND

HUM

NO HUM

Dehumidification

System

Humidification

System

Page 5.7

CK1 and CK2 terminals wired to a Time Clock

For instructions on wiring the optional Remote and Outdoor

Sensors, please see page 16.2 of the Owner’s Manual

5

W2

MISC1

RS2

MISC3

RS+5

RS1

RSGND

W1/O/B

Y1

G

MISC2

CK1

CKGND

R

C

10

9

11

12

8

7

6

1

2

3

5

4

DRY CONTACT SWITCH - The terminals are ‘normally open’ (or may be programmed for

normally closed operation, see page 17.2 of the Owner’s Manual). Closing or

completing the circuit will cause the thermostat to do one of the following:

1) If Vacation is selected in step #41 of the Advanced Setup (see page 17.3 of the

Owner’s Manual), when the dry contact is energized the thermostat will be forced into

Vacation mode (see Section 20 of the Owner’s Manual).

2) If Service Pan is selected, when the dry contact is energized the thermostat will lockout

Y1 (compressor) and write Service Pan on the display.

Page 5.8

SECTION 6

Test Operation

AUTO

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Turn the power on to the Heating/Air Conditioning system.

6

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Press the MODE button repeatedly until the

HEAT icon appears on the display. Press the

UP or DOWN buttons until the set temperature is

10 degrees above room temperature. The furnace should turn on.

Press the MODE button repeatedly until the

COOL icon appears on the display. Press the UP or DOWN buttons until the set temperature is 10 degrees below room temperature. The air conditioner should turn on. NOTE: Most equipment has a time delay of 5 minutes between cool cycles. This feature is defeatable on the thermostat. Consult the Owner's Manual under

Setup, cycles per hour (page 14.3).

Press the UP button until the setpoint is equal to the room temperature. Press the FAN button to Fan On. The fan should turn on and run continuously.

Page 6.1

SECTION 7

Calibrating the Thermostat Sensors

Under normal circumstances it will not be necessary to adjust the calibration of the temperature and humidity sensors. If calibration is required, please contact a trained HVAC technician to correctly perform the following procedure.

MODE

Place the thermostat in the

OFF mode.

OFF

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7

MODE

FAN

Press and hold the MODE button. While holding the

MODE button, press and hold the FAN button for 5 seconds.

All icons will appear on the display.

I8:88

Morning

DayNight

Evening

FanOn

Am

Pm

SuMoTuWeThFrSa

Service Filter

Pan UV Light

AUTO

OFFON

Program On

StartStop

DeHumidify

I88 Setup

H I

88

C OOL

Outside

Vacation

A UX H EAT

L

O

88

PRESS

THERMOSTAT SENSOR

Press the UP and DOWN buttons at the same time twice. The thermostat temperature will be displayed and may be calibrated using the UP or DOWN buttons.

CALIBRATE

TWICE

MODE

MODE

REMOTE SENSOR

Press the MODE button once. The remote sensor temperature will be displayed and may be calibrated using the

UP or DOWN buttons. If a remote sensor is not installed, only dashes will appear.

HUMIDITY SENSOR

Press the MODE button once. The relative humidity at the thermostat will be displayed and may be calibrated using the

UP or DOWN buttons.

Outside

CALIBRATE

CALIBRATE

After calibration is complete, press the MODE button once to return to normal operation.

Page 7.1

SECTION 8

TroubleShooting

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SYMPTOM: The air conditioning does not attempt to

turn on.

CAUSE: The compressor timer lockout may prevent the

air conditioner from turning on for a period of time.

REMEDY: Consult the Owner's Manual in the Setup

section to defeat the cycles per hour and

compressor timeguard.

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SYMPTOM: The display is blank.

CAUSE: Lack of proper power.

REMEDY: Make sure power is turned on to the furnace

and that you have 24vac between R & W. If C is

used, 24vac between R & C.

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SYMPTOM: The air conditioning does not attempt to

turn on.

CAUSE: The cooling setpoint is set too high.

REMEDY: Consult the Owner's Manual in the Setup

section to lower the cooling setpoint limit.

SYMPTOM: The heating does not attempt to turn on.

CAUSE: The heating setpoint is set too low.

REMEDY: Consult the Owner's Manual in the Setup

section to raise the heating setpoint limit.

Page 8.1

TroubleShooting

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SYMPTOM: When controlling a residential heat pump,

and asking for cooling, the heat comes on.

CAUSE: The thermostat reversing valve jumper is set

for “b”.

REMEDY: Set the reversing valve jumper for “O”. See

pages 5.4 and 5.5.

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SYMPTOM: When calling for cooling, both the heat

and cool come on.

8

CAUSE: The thermostat equipment jumper is configured

for “HP” and the HVAC unit is a Gas/Electric.

REMEDY: Set the equipment jumper for “Gas”. See

pages 5.2 and 5.3.

Page 8.2

P/N 88-600

Rev. 1