American Standard Thermostat Ceratherm R540 Manual

The American Standard Ceratherm R540 is a programmable digital thermostat designed for residential heating and cooling systems. It features a backlit LCD display, 7-day programming capability, automatic changeover between heating and cooling modes, temperature hold functions, and compatibility with most single-stage HVAC systems. Below are key sections for safety, features, installation, programming, operation, and troubleshooting.

Features at a Glance

Key components: Backlit LCD display, Program buttons, System switch (Heat/Cool/Auto/Off), Fan switch (Auto/On), Temperature adjustment buttons, Hold button.

Installation

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

1. Remove old thermostat: Turn off power, remove cover, label wires, disconnect from terminals.
2. Mount new baseplate: Level and secure to wall using provided screws.
3. Connect wires: Match labeled wires to corresponding terminals (R, W, Y, G, C, etc.).
4. Install batteries: Insert 2 AA batteries for backup power.
5. Attach thermostat: Snap onto baseplate until it clicks into place.
6. Restore power: Turn circuit breaker back on.

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, configure initial settings.

1. Set time and day: Press TIME button, use arrows to set correct time and day.
2. Select temperature format: In SETUP menu, choose Fahrenheit or Celsius.
3. Configure system type: Match to your HVAC system (conventional heat pump, etc.).
4. Set filter change interval: Program reminder for every 30-90 days as needed.
5. Test operation: Run system in Heat and Cool modes to verify proper function.

CAUTION! Ensure correct system configuration to prevent equipment damage.

Specifications

• Power Requirements: 24V AC from HVAC system; 2 AA battery backup.
• Temperature Range: Heating: 40°F to 90°F (4°C to 32°C); Cooling: 50°F to 99°F (10°C to 37°C).
• Display: Backlit LCD with temperature and status indicators.
• Compatibility: Single-stage heating and cooling systems; conventional or heat pump.
• Programming: 4 time periods per day, 7-day programmable.
• Accuracy: ±1°F (±0.5°C).
• Operating Environment: 32°F to 105°F (0°C to 40°C); 0-90% RH non-condensing.
• Wiring Terminals: R, Rc, Rh, W, Y, G, C, O/B (heat pump models).

Controls and Settings

Access menus via MENU button. Front Panel: System switch, Fan switch, Temperature buttons, Hold, Menu, Time, Day.

Display Indicators: Heat/Cool/Auto mode, Fan On/Auto, Hold active, Battery low, Filter alert.

System Settings: Heat/Cool/Auto/Off selection. Fan Settings: Auto or Continuous operation. Programming: Set 4 periods per day (Wake, Leave, Return, Sleep). Temperature Settings: Heating and cooling setpoints with 1°F increments. Setup Menu: Time format (12/24 hr), temperature format (°F/°C), filter change interval, system configuration.

Wiring Configuration

Standard terminal designations for HVAC systems.

1. R/Rc/Rh: 24V AC power (R for single transformer; Rc/Rh for separate heating/cooling).
2. W: Heat stage 1 (conventional) or auxiliary heat (heat pump).
3. Y: Cool stage 1 (compressor).
4. G: Fan relay.
5. C: Common (24V AC return).
6. O/B: Heat pump reversing valve (O for cooling energized; B for heating energized).

Tip: Refer to HVAC system manual for correct wiring. Take photo of old thermostat wiring before removal.

Programming Schedule

Create energy-saving schedule for heating and cooling.

1. Enter programming mode: Press MENU, select PROGRAM.
2. Select day: Choose individual days or copy to all days.
3. Set periods: Program 4 time periods (Wake, Leave, Return, Sleep) with start times.
4. Set temperatures: Assign heating and cooling setpoints for each period.
5. Save program: Press DONE to save and exit.
6. Temporary override: Press HOLD to temporarily adjust temperature (resumes schedule at next period).
7. Vacation mode: Press HOLD for 3 seconds to set extended hold period.

WARNING! Do not set extreme temperature differentials (more than 5°F) between periods to prevent system strain.

Energy Saving Features

Automatic Changeover: Maintains comfort while minimizing energy use. Adaptive Recovery: Learns system recovery time to reach setpoints at scheduled times. Temperature Limits: Set minimum heating and maximum cooling temperatures in installer menu. Filter Change Alert: Reduces energy consumption by maintaining proper airflow.

Care & Maintenance

Clean exterior with soft, dry cloth. Do not use liquids or cleaners. Replace batteries annually or when low battery indicator appears. Check and replace HVAC air filter when filter alert activates.

CAUTION! Never spray cleaning fluids directly on thermostat. Ensure power is off before removing cover.

Regulatory Information

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

Troubleshooting

Reset: Remove batteries, turn off power for 30 seconds, restore power and batteries to factory reset.

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