American Standard Thermostat ASYSTAT656 Manual

The American Standard ASYSTAT656 is a programmable digital thermostat designed for precise temperature control of HVAC systems. It features a backlit LCD display, 7-day programming capability, automatic changeover between heating and cooling modes, filter change reminder, system status indicators, and compatibility with most 24VAC heating and cooling systems. 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. Wiring Configuration 7. Programming Schedule 8. Advanced Features 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Backlit LCD display, Menu/Select button, Up/Down arrows, System switch (Heat/Cool/Off/Auto), Fan switch (Auto/On), Hold button, Program button.

Feature	Description
7-Day Programmable	Set different schedules for each day of the week
Automatic Changeover	Automatically switches between heating and cooling based on setpoint
Backlit Display	Easy-to-read screen with adjustable backlight
Filter Change Reminder	Alerts when it's time to replace the HVAC filter
System Status Indicators	Icons for Heat, Cool, Fan On, Hold, etc.
Temperature Display	Shows current room temperature and setpoint
Battery Backup	Maintains program during power outages (2 AA batteries)
Compatibility	Works with most 24VAC single-stage and multi-stage systems
Temperature Range	40°F to 99°F (4°C to 37°C)
Temperature Swing	Adjustable differential for precise control

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 wire labels to terminal designations (R, C, W, Y, G, etc.).
Attach thermostat: Align and snap onto baseplate.
Restore power and configure settings.

WARNING! Electrical shock hazard. Always turn off power before installation. If unsure, consult a qualified HVAC technician.

First-Time Setup

After installation and power restoration, follow initial setup procedure.

Set time and day: Press MENU, navigate to CLOCK SETTINGS.
Select temperature format: Choose between Fahrenheit (°F) or Celsius (°C).
Configure system type: Select appropriate heating/cooling system (Conventional, Heat Pump).
Set filter reminder interval: Default is 90 days (adjustable).
Program schedule: Set 4 periods per day (Wake, Leave, Return, Sleep).

CAUTION! Ensure correct wiring before restoring power to prevent equipment damage.

Specifications

Power Requirements: 24VAC from HVAC system; Battery backup (2 AA batteries).
Display: Backlit LCD with temperature and status icons.
Programming: 7-day, 4 periods per day.
Temperature Range: 40°F to 99°F (4°C to 37°C).
Accuracy: ±1°F (±0.5°C).
Compatibility: Most 24VAC heating and cooling systems (1-2 stages).
Terminals: R, C, W, Y, G, O/B, Aux/E, L (for common wire, heat pump, etc.).
Operating Environment: 32°F to 122°F (0°C to 50°C); 0-90% RH non-condensing.
Dimensions: 5.5" x 3.5" x 1" (140mm x 89mm x 25mm).

Controls and Settings

Front panel buttons: MENU/SELECT, UP/DOWN arrows, SYSTEM (Heat/Cool/Off/Auto), FAN (Auto/On), HOLD, PROGRAM.

Menu Navigation: Press MENU to access settings: Clock, Schedule, System, Filter, Temperature Format, Temperature Swing, Backlight, Factory Reset.

Temperature Adjustment: Use UP/DOWN arrows to change setpoint. Hold Function: Press HOLD to maintain current temperature indefinitely (press again to resume schedule). Program Override: Temporary override without changing programmed schedule. System Switch: HEAT (heating only), COOL (cooling only), AUTO (automatic changeover), OFF (system off). Fan Switch: AUTO (fan runs with heating/cooling cycles), ON (continuous fan operation).

Wiring Configuration

Standard terminal designations for 24VAC systems.

R (Red): 24VAC power from transformer.
C (Blue/Black): Common wire for continuous power.
W (White): Heat stage 1.
Y (Yellow): Cooling stage 1.
G (Green): Fan relay.
O/B (Orange): Heat pump reversing valve.
Aux/E (Brown): Auxiliary heat or emergency heat.
L (Not always used): System indicator.

Tip: Take a photo of old thermostat wiring before disconnecting. Refer to wiring diagram in manual for your specific system type.

Programming Schedule

Create energy-saving schedules with 4 periods per day.

Press PROGRAM button to enter programming mode.
Select day: Choose ALL DAYS, WEEKDAYS, WEEKENDS, or individual days.
Set Period 1 (Wake): Time and temperature for morning.
Set Period 2 (Leave): Time and temperature for when away.
Set Period 3 (Return): Time and temperature for evening return.
Set Period 4 (Sleep): Time and temperature for nighttime.
Copy schedule: Copy settings to other days to save time.
Exit programming: Press MENU to save and exit.

WARNING! Do not set extreme temperature differentials (more than 10°F) between periods as it may cause system strain.

Advanced Features

Automatic Changeover: In AUTO mode, thermostat switches between heating and cooling based on setpoint. Filter Change Reminder: Programmable interval (30-365 days); reset after filter replacement. Temperature Swing: Adjust differential between 0.5°F and 3°F for finer control. Backlight Settings: Adjust duration (5-60 seconds) or set to always on. System Test: Run system test to verify proper operation of heating, cooling, and fan.

Care & Maintenance

Clean with soft, dry cloth only. Do not use liquids or abrasive cleaners. Replace batteries annually or when low battery icon appears. Check and replace HVAC filter as indicated by reminder.

CAUTION! Do not spray cleaning agents directly on thermostat. Ensure power is off before cleaning around wiring.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits for residential use. UL Listed: Meets safety standards. Copyright © American Standard Heating & Air Conditioning. For support, visit www.americanstandardair.com or contact 1-800-228-2962.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Blank display	Power loss/dead batteries	Check circuit breaker; replace batteries; verify wiring at R and C terminals.
System not turning on	Incorrect settings/wiring	Verify SYSTEM switch setting; check wiring connections; ensure setpoint is above/below room temperature.
Incorrect temperature reading	Location/calibration	Relocate thermostat away from heat sources/drafts; check calibration in menu.
Schedule not following program	Hold active/program error	Check if HOLD is activated; review programmed schedule times and temperatures.
Short cycling	Temperature swing too small	Increase temperature swing setting in menu (recommended 1.5°F).

Reset: Menu > Settings > Factory Reset to restore default settings (erases all programming).

Service: 1-800-228-2962; www.americanstandardair.com