Common Symptoms

If you're experiencing any of these symptoms, you may have this problem:

Furnace runs briefly then shuts off
Frequent on/off cycles
House never gets warm enough
Higher heating bills

Possible Causes & Solutions

Dirty Air Filter

DIY Possible

Replace the air filter

Overheating

Pro Required

Professional inspection for airflow issues

Faulty Flame Sensor

Pro Required

Sensor cleaning or replacement

Thermostat Problems

Pro Required

Thermostat repair or replacement

Oversized Furnace

Pro Required

Professional assessment needed

When to Call a Professional

While some issues have DIY solutions, HVAC systems are complex. Call a professional when:

  • DIY solutions don't resolve the problem
  • The issue involves electrical components
  • You smell gas or burning odors
  • The problem returns after temporary fixes
  • Your system is under warranty (DIY repairs may void it)
Call San Jose HVAC Pros: (650) 397-7060

Frequently Asked Questions

Why won't my furnace turn on?

Common causes include a tripped circuit breaker, thermostat issues, pilot light problems, or a faulty ignition system. We can diagnose all furnace issues.

My furnace is making strange noises. What does it mean?

Different noises indicate different issues: banging may mean delayed ignition, squealing could be a belt issue, and rumbling might indicate a burner problem.

How often should I change my furnace filter?

Standard filters should be changed every 1-3 months depending on usage, pets, and allergies. Higher-quality filters may last longer but check monthly.

Is a cracked heat exchanger dangerous?

Yes, a cracked heat exchanger can leak carbon monoxide, which is dangerous. If suspected, turn off your furnace immediately and call for service.

Need Help With Furnace Cycling?

San Jose HVAC Pros technicians are ready to diagnose and fix your problem

Tap to Call Book Online