Trane XE78 Furnace Manual

The Trane XE78 is a high-efficiency gas furnace designed for residential heating applications. This model features advanced combustion technology, variable-speed blower motor, electronic ignition, and multiple safety systems. The XE78 series offers reliable performance with AFUE ratings up to 96%, making it an energy-efficient choice for home heating. Below are key sections covering safety, features, installation, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation Requirements 3. First-Time Setup 4. Technical Specifications 5. Controls and Operation 6. Venting and Combustion Air 7. Maintenance Procedures 8. Safety Systems 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Variable-speed ECM blower motor, hot surface igniter, induced draft motor, stainless steel heat exchanger, multi-speed settings, diagnostic LED system.

Feature	Description
Variable-speed ECM motor	Provides efficient airflow and quiet operation
Stainless steel heat exchanger	Durable construction with extended warranty
Hot surface ignition	Reliable electronic ignition system
Induced draft motor	Ensures proper venting and combustion
Multi-speed blower	Adjustable airflow for optimal comfort
Diagnostic LED	Provides error codes for troubleshooting
Safety shut-off switches	Multiple safety systems for protection
AFUE up to 96%	High efficiency rating for energy savings
Compact design	Fits in standard furnace closets
Quiet operation	Sound-insulated cabinet design

Installation Requirements

Professional installation required. Ensure proper clearances and venting.

Location: Install in approved furnace closet or mechanical room with proper clearances.
Venting: Use approved PVC pipe for direct vent installation.
Gas connection: Use black iron pipe with proper sizing for BTU input.
Electrical: 120V AC power supply with proper grounding.
Ductwork: Ensure proper sizing and sealing for optimal airflow.

WARNING! Gas furnace installation must be performed by qualified HVAC technician. Improper installation can cause fire, explosion, or carbon monoxide poisoning.

First-Time Setup

Initial startup must be performed by qualified technician.

Verify installation: Check all connections, clearances, and venting.
Gas pressure check: Measure and adjust manifold pressure per specifications.
Electrical connections: Verify proper voltage and grounding.
Startup sequence: Follow manufacturer's startup procedure.
System check: Verify proper operation of all safety controls.
Customer orientation: Explain thermostat operation and basic maintenance.

CAUTION! Never attempt to adjust gas pressure or electrical connections without proper training and equipment.

Technical Specifications

Model Series: XE78
Fuel Type: Natural Gas or Propane
Input BTU: 40,000 - 120,000 BTU/hr
AFUE Rating: Up to 96%
Blower Motor: Variable-speed ECM
Electrical: 120V AC, 60Hz
Gas Connection: 1/2" NPT
Venting: 2" or 3" PVC
Dimensions: Varies by model size
Weight: 85-145 lbs depending on model

Controls and Operation

Integrated control board manages all furnace functions. Access panel must be properly installed for safe operation.

Thermostat Settings: HEAT, COOL, OFF, FAN AUTO/ON. Recommended temperature setting: 68°F winter, 78°F summer.

Control Board Features: Diagnostic LED (flashes error codes), dip switches for configuration, safety lockout system, blower control, gas valve control.

Operating Modes: Heating cycle, fan-only operation, standby mode, safety shutdown.

Venting and Combustion Air

Direct vent system required. Follow local codes and manufacturer specifications.

Vent pipe: Use schedule 40 PVC, minimum 2" diameter.
Vent termination: Maintain proper clearances from windows, doors, and air intakes.
Combustion air: Provide adequate fresh air supply.
Slope: Vent pipes must slope back to furnace for condensate drainage.

Tip: Regular inspection of vent system is essential for safe operation.

Maintenance Procedures

Annual maintenance by qualified technician recommended.

Air filter: Replace every 1-3 months depending on usage.
Heat exchanger: Visual inspection for cracks or damage.
Blower assembly: Clean blower wheel and housing annually.
Burners: Clean and inspect for proper flame pattern.
Vent system: Inspect for obstructions or damage.
Drain system: Clean condensate trap and drain lines.
Safety controls: Test operation of all safety switches.

WARNING! Turn off power and gas supply before performing any maintenance.

Safety Systems

Multiple safety features protect against hazardous conditions. Flame rollout switch, high limit switch, pressure switch, igniter safety, gas valve safety shutoff.

Care & Cleaning

Keep area around furnace clean and clear. Use soft brush for cleaning components. Never use water or cleaning chemicals on electrical components.

CAUTION! Always disconnect power before cleaning. Use only approved methods and materials.

Regulatory Information

UL listed, ANSI Z21.47 compliant. Meets DOE energy efficiency standards. Installation must comply with National Fuel Gas Code (NFPA 54), local building codes, and manufacturer specifications. For technical support, contact Trane Residential at 1-800-554-6413 or visit www.trane.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, safety lockout	Check circuit breaker, thermostat settings, diagnostic LED codes.
No heat	Gas supply, igniter, pressure switch	Verify gas valve on, check igniter operation, inspect pressure switch.
Blower won't run	Motor, capacitor, control board	Check motor operation, test capacitor, inspect control board.
Furnace cycles on limit	Airflow restriction, dirty filter	Replace air filter, check for blocked vents, verify blower speed.
Error codes flashing	Various system faults	Refer to diagnostic chart in service manual for specific code.

Reset: Turn power off for 30 seconds, then restore power.

Service: 1-800-554-6413; www.trane.com