Atwood Excaliber Furnace Installation Manual

The Atwood Excaliber Furnace is a high-efficiency heating system designed for residential and light commercial applications, featuring advanced combustion technology, multiple venting options, electronic ignition, variable-speed blower motor, digital thermostat compatibility, safety shutoff controls, and energy-saving operation modes. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

Features at a Glance

Key components: High-efficiency heat exchanger, electronic control board, combustion chamber, blower assembly, gas valve, venting system, and safety controls.

Installation

Unpack and inspect all components. Ensure installation location meets clearance requirements.

1. Select installation location: Minimum 18" clearance from combustible materials.
2. Prepare mounting surface: Level, solid foundation capable of supporting unit weight.
3. Install venting system: Follow local codes for proper vent sizing and routing.
4. Connect gas supply: Use approved gas piping; pressure test before connection.
5. Connect electrical: 120V AC power supply with proper grounding.
6. Connect thermostat: Use 18-gauge thermostat wire for proper communication.

WARNING! Furnace is heavy; use proper lifting equipment. Gas connection must be performed by licensed professional.

First-Time Setup

Power on furnace; follow startup sequence.

1. Verify gas supply: Ensure gas valve is open and pressure is correct.
2. Check electrical: Confirm proper voltage at control board.
3. Set thermostat: Program desired temperature settings.
4. Test ignition sequence: Observe startup cycle for proper operation.
5. Adjust blower speed: Set appropriate CFM for duct system.
6. Check temperature rise: Verify within specified range on rating plate.

CAUTION! Ensure proper ventilation and combustion air supply. Test carbon monoxide detectors.

Specifications

• Heating Capacity: 40,000 - 120,000 BTU/h (model dependent)
• Efficiency: 80% - 96% AFUE (model dependent)
• Gas Type: Natural gas or LP/propane (field convertible)
• Electrical: 120V AC, 60Hz, 3-8 amps
• Venting: Category I or IV (model dependent)
• Airflow: 800 - 2000 CFM (variable speed)
• Dimensions: Varies by model (check specific model data)
• Weight: 80 - 150 lbs (model dependent)
• Operating Temp Range: -30°F to 120°F ambient

Controls and Settings

Access control board via front panel. DIP switches for configuration settings.

Control Board: LED status indicators, diagnostic codes, reset button, DIP switch bank.

Configuration: Blower speed settings (COOL, HEAT, FAN), gas type (NAT/LP), venting type, thermostat type (single/multi-stage). Operation: Temperature control, fan operation (auto/on), system mode (heat/cool/off). Diagnostics: Error code display, lockout reset, system status monitoring.

Connecting Components

Gas supply: 1/2" to 1" black iron pipe. Electrical: 120V AC power. Thermostat: 2-8 wire connection. Venting: PVC, CPVC, or metal as required.

1. Turn off gas and electrical power before making connections.
2. Match connections to specifications (gas pressure, wire gauge, vent size).
3. Test all connections for leaks and proper operation.

Tip: Use pipe thread sealant approved for gas applications. Pressure test gas line before final connection.

Operating Procedures

Supports automatic and manual operation modes.

1. Startup: Set thermostat to desired temperature above room temperature.
2. Normal operation: Furnace will cycle automatically based on thermostat setting.
3. Fan control: Set to AUTO for temperature-controlled operation or ON for continuous airflow.
4. Shutdown: Set thermostat to OFF position or below room temperature.
5. Emergency shutdown: Turn off gas supply and electrical power at service switches.

WARNING! Do not attempt to override safety controls. If furnace fails to start, wait 5 minutes before retry.

Safety Features

Flame Rollout Switch: Shuts off gas if flame extends outside combustion chamber. High Limit Switch: Prevents overheating by interrupting gas valve operation. Pressure Switch: Ensures proper venting before allowing ignition. Flame Sensor: Confirms burner ignition within trial-for-ignition period.

Maintenance & Cleaning

Turn off power and gas supply before maintenance. Clean or replace air filter monthly during heating season. Annual professional inspection recommended.

CAUTION! Do not operate without air filter. Keep combustion air intake clear of obstructions.

Regulatory Information

UL certified; complies with ANSI Z21.47 standards for gas-fired central furnaces. CSA certified for Canadian installations. Meets DOE energy efficiency standards. For support, visit www.atwoodmobile.com or contact 1-800-555-HEAT. Installation must comply with local building codes and NFPA 54.

Troubleshooting

Reset: Power cycle unit or press reset button on control board.

Service: 1-800-555-HEAT; www.atwoodmobile.com