American Standard Thermostat ACONT203AS42MA Manual

The American Standard ACONT203AS42MA is a programmable thermostat designed for residential HVAC systems, offering precise temperature control, energy-saving scheduling, and compatibility with single-stage heating and cooling equipment. It features a backlit digital display, intuitive menu navigation, and a 7-day programmable schedule. Below are key sections for safety, features, installation, programming, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting to HVAC System 7. Programming Schedule 8. Energy-Saving Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Digital display, Menu/Select button, Up/Down arrows, Hold button, Fan button, System button (Heat/Cool/Off), Program button.

Feature	Description
Digital Display	Backlit LCD showing temperature, time, and system status
7-Day Programmable	Allows different schedules for each day of the week
Temperature Range	40°F to 99°F (Heat), 50°F to 99°F (Cool)
Hold Function	Temporarily overrides programmed schedule
Filter Change Reminder	Alerts when HVAC filter needs replacement
Battery Backup	Uses AA batteries to retain settings during power loss
System Switch	Selects Heat, Cool, or Off mode
Fan Control	Auto or On settings for blower fan
Energy Star Certified	Meets energy efficiency guidelines
Compatibility	Works with most 24VAC single-stage systems

Installation

Turn off power to HVAC system at circuit breaker before installation.

Remove old thermostat: Label wires, disconnect from terminals.
Mount new baseplate: Level and secure to wall using provided screws.
Connect wires: Match labeled wires to corresponding terminals (R, W, Y, G, C).
Attach thermostat: Align and snap onto baseplate.
Install batteries: Insert two AA batteries for backup power.
Restore power: Turn circuit breaker back on.

WARNING! Electrical shock hazard. Ensure power is off before handling wires. If unsure, consult a qualified HVAC technician.

First-Time Setup

After power restoration, follow initial configuration.

Set time and day: Press Menu, navigate to Time/Day settings.
Select temperature format: Choose Fahrenheit or Celsius.
Configure system type: Confirm single-stage Heat/Cool.
Set filter reminder interval: Default 90 days (adjustable).
Review default program: Four periods per day (Wake, Leave, Return, Sleep).

CAUTION! Do not force thermostat onto baseplate. Ensure wires are not pinched.

Specifications

Power Requirements: 24VAC from HVAC system; two AA backup batteries.
Display: Backlit digital LCD.
Program Capacity: 7-day, 4 periods per day.
Temperature Control: 1°F increments.
Compatibility: Single-stage conventional and heat pump systems (requires C wire for continuous power).
Operating Environment: 32°F to 105°F, 0% to 90% relative humidity (non-condensing).
Warranty: 5-year limited warranty from date of purchase.
Certifications: Energy Star, UL listed.

Controls and Settings

Access settings via Menu button. Navigate with Up/Down arrows, select with Menu.

Front Panel: Display, Menu/Select, Up/Down arrows, Hold, Fan, System, Program.

Menu Options: Time/Day, Temperature Format, Program Schedule, Filter Reminder, System Test, Factory Reset.

System Settings: Heat (single-stage), Cool (single-stage), Off, Emergency Heat (if applicable). Fan: Auto (runs with HVAC), On (continuous).

Connecting to HVAC System

Terminal labels: R (24VAC power), W (Heat), Y (Cool), G (Fan), C (Common).

Verify HVAC system type (conventional single-stage).
Match thermostat wires to terminals (refer to old thermostat labels).
Ensure C wire is connected for optimal operation (if available).
After connection, test each mode (Heat, Cool, Fan) for proper operation.

Tip: Take a photo of old thermostat wiring before disconnecting for reference.

Programming Schedule

Default schedule: Wake (6:00 AM), Leave (8:00 AM), Return (6:00 PM), Sleep (10:00 PM).

Press Program button to enter schedule mode.
Select day (Mon-Fri, Sat, Sun, or All).
Edit period times using Up/Down arrows.
Set desired temperature for each period.
Press Menu to save and move to next period.
Press Hold to temporarily override schedule; press again to resume.

WARNING! Do not set extreme temperatures that could damage HVAC system or cause discomfort.

Energy-Saving Features

Programmable schedule reduces energy use when away. Filter reminder ensures efficient airflow. Temperature setbacks during sleep and away periods.

Care & Cleaning

Turn off power before cleaning. Use soft, dry cloth to wipe display and casing. Do not use liquids or abrasive cleaners.

CAUTION! Do not spray cleaning agents directly on thermostat. Avoid static electricity near display.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits for residential use. Copyright © American Standard Heating & Air Conditioning. For support, visit www.americanstandard.com or contact 1-800-428-4328.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Blank display	Power loss, dead batteries	Check circuit breaker; replace AA batteries.
HVAC not turning on	Incorrect wiring, system mode	Verify wire connections; ensure System is set to Heat or Cool.
Incorrect temperature reading	Location, drafts	Relocate thermostat away from heat sources, drafts, or direct sunlight.
Schedule not following	Hold active, programming error	Press Hold to resume schedule; reprogram periods.
Short cycling	Wiring, system issues	Check C wire connection; consult HVAC technician.

Reset: Menu > Settings > Factory Reset (erases all custom settings).

Service: 1-800-428-4328; www.americanstandard.com