Venstar T0140 User Manual

Venstar Inc. 05/08
Digital
Thermostat
Digital
Thermostat
residential
T0140
THERMOSTAT
OWNER’S
MANUAL
OWNER’S
MANUAL
Use with most 1 or 2 Stage Heat Pump Heat and 1 stage Heat Pump Cool units
Stages: 2-Heat, 1-Cool
Battery or System Powered
Auxiliary Heat Indicator
Fahrenheit or Celsius
PROGRAMMABLE
NON-
PROGRAMMABLE
NON-
up to
& 1-cool
up to
& 1-cool
2-heat
2-heat
HEAT
PUMP
HEAT
PUMP
Bi-Color LED (when system powered)

Venstar T0140 Specifications

General

Type	Programmable Thermostat
Display	Digital
Programmable	Yes
Backup Battery	Yes
Temperature Range	45°F to 90°F
Power Source	24V AC
Features	Touchscreen
Weight	0.5 lbs

Summary

Safety Warnings and Precautions

Power Disconnection for Installation

Mandatory step to disconnect power to HVAC before thermostat installation.

Battery Replacement Guidelines

Normal Thermostat Operation

Selecting Mode and Setting Temperature

Guide to choosing the operating mode and adjusting the desired temperature.

Fan Operation Modes (Auto/On)

Auxiliary Heat Functionality

Emergency Aux Heat Mode

Engages auxiliary heat, disabling the compressor for heating.

Normal Aux Heat Mode

Aux Heat Lockout Mode

Installation Preparation Steps

Electrical Power Safety

Critical instruction to disconnect electrical power at the main panel before installation.

Removing and Installing Thermostat

Wire Identification and Management

Instructions for disconnecting, taping, and marking wires for easy reconnection.

Connecting Thermostat Wiring

Terminal Mapping for Wiring

Chart matching old thermostat terminals to the new thermostat's connector terminals.

Wiring Diagram: 4-Wire Heat Pump (O Valve)

Wiring Diagram: 5-Wire Heat Pump (O Valve, Aux Heat)

Wiring Diagram: 4-Wire Heat Pump (B Valve)

Wiring Diagram: 5-Wire Heat Pump (B Valve, Aux Heat)

Test Operation: Heating System

Verifying Heating Mode Activation

Steps to test the heating function by setting the temperature higher than room temp.

Testing Auxiliary Heat Engagement

Checking if the auxiliary heat activates correctly in Normal mode.

Test Operation: Cooling and Fan

Verifying Cooling Mode Activation

Steps to test the cooling function by setting the temperature lower than room temp.

Verifying Fan Continuous Operation

Procedure to confirm the fan runs continuously when the system is off.

Troubleshooting Common Issues

Difficult Slide Switch Operation

Air Conditioning System Not Starting

Troubleshooting steps for when the AC fails to turn on.

Fan Not Activating with Compressor

Troubleshooting Advanced Issues

Auxiliary Heat Not Engaging

Heating System Failure to Start