Intertherm Furnace Manual Troubleshooting

The Intertherm Furnace is a reliable heating system designed for residential use, featuring multiple safety mechanisms, efficient heat exchange, and user-friendly controls. This troubleshooting guide covers common issues, diagnostic procedures, and corrective actions to help maintain optimal performance. Below are key sections for safety precautions, common problems, diagnostic steps, and maintenance tips.

1. Safety Precautions 2. Common Issues 3. Diagnostic Procedures 4. Component Specifications 5. Control Settings 6. Maintenance Guidelines 7. Error Code Interpretation 8. Professional Service 10. Regulatory Information 11. Troubleshooting Table

Safety Precautions

Before troubleshooting, ensure safety: Turn off power at circuit breaker, wear protective gear, and verify gas supply is off if applicable.

Precaution	Description
Power Disconnect	Always shut off electrical power before inspection
Gas Valve	Turn off gas supply when checking combustion components
Protective Gear	Wear gloves and safety glasses during maintenance
Ventilation	Ensure proper airflow to prevent carbon monoxide buildup
Clearance	Maintain recommended clearances from combustible materials

Common Issues

Typical problems include ignition failure, blower malfunctions, and thermostat communication errors.

No heat production: Check thermostat setting, power supply, and gas valve.
Insufficient heating: Inspect air filters, ductwork, and heat exchanger.
Frequent cycling: Examine thermostat calibration and limit switches.
Unusual noises: Assess blower motor, bearings, and duct vibrations.

WARNING! Do not attempt repairs beyond your skill level; contact certified technicians for complex issues.

Diagnostic Procedures

Systematic approach to identify faults: Start with power and thermostat, then move to components.

Verify power: Check circuit breaker and furnace switch.
Thermostat test: Set to heat mode above room temperature.
Pilot light/ignition: Observe for spark or flame; listen for gas valve click.
Blower operation: Listen for motor startup; check airflow.
Limit switches: Use multimeter to test continuity.

CAUTION! Avoid contact with high-voltage components; refer to wiring diagram if needed.

Component Specifications

Voltage: 120V AC, 60Hz.
Gas Type: Natural gas or propane (model dependent).
BTU Rating: Varies by model (e.g., 50,000-100,000 BTU).
Blower Motor: Single-speed or variable; lubricated bearings.
Heat Exchanger: Stainless steel or aluminized steel construction.
Thermostat Compatibility: Low-voltage (24V) systems.
Filter Size: Standard 16x25x1 inch or model-specific.
Vent Requirements: Category I venting for natural draft.

Control Settings

Access via thermostat or furnace control board. Common adjustments: fan control, temperature limits, ignition sequence.

Thermostat: HEAT/COOL/OFF mode, temperature setpoint, fan AUTO/ON.

Furnace Controls: Power switch, gas valve knob, reset button (red). Control Board: LED indicators for status codes; dip switches for blower timing. Safety Limits: High-limit switch auto-reset; rollout switch manual reset.

Maintenance Guidelines

Regular upkeep prevents issues: Monthly filter checks, annual professional inspection.

Filter replacement: Every 1-3 months during heating season.
Blower cleaning: Vacuum dust annually; lubricate motor if required.
Vent inspection: Ensure exhaust and intake are unobstructed.
Burner cleaning: Remove debris; verify flame pattern (blue with yellow tips).

Tip: Keep area around furnace clear; maintain 1-foot clearance for airflow.

Error Code Interpretation

LED flash patterns indicate specific faults. Refer to control board chart.

1 Flash: Ignition lockout - check gas supply, igniter, flame sensor.
2 Flashes: Pressure switch fault - inspect tubing, inducer motor.
3 Flashes: Limit circuit open - verify airflow, filter, duct restrictions.
4 Flashes: Rollout switch tripped - examine burners, heat exchanger.
5 Flashes: Gas valve error - test valve voltage and wiring.

WARNING! Multiple lockouts may require professional diagnosis; do not bypass safety devices.

Professional Service

Contact certified technicians for: Gas line work, heat exchanger cracks, electrical repairs, warranty claims.

Regulatory Information

ANSI Z21.47: Certified for safety standards. UL listed. For support, visit www.intertherm.com or contact 1-800-XXX-XXXX. Installation must comply with local codes and NFPA 54.

Troubleshooting Table

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power loss/thermostat	Check breaker, furnace switch; set thermostat above room temp.
No heat (blower runs)	Ignition system	Verify gas valve on; inspect igniter, flame sensor.
Short cycling	Dirty filter/limit switch	Replace filter; check airflow; reset limit switch.
Blower not running	Motor/control board	Test motor capacitor; check control board signals.
Gas odor	Leak/improper combustion	Evacuate immediately; call gas company; do not operate.

Reset Procedure: Turn off power for 30 seconds; restore power.

Service: 1-800-XXX-XXXX; www.intertherm.com