When your furnace isn’t operating properly, some problems can be fixed quickly, while others need a professional’s touch. Below is a walkthrough of common furnace issues and what you can check before calling an HVAC technician.
1. Check the Thermostat First
Before assuming the furnace itself is at fault, start with the thermostat:
- Confirm it’s set to “Heat”
- Increase the temperature setting above room temp
- Replace batteries if needed
Sometimes a simple thermostat adjustment can solve a no-heat situation.
2. Inspect and Replace the Air Filter
A dirty or clogged filter restricts airflow and can make your furnace overheat or shut down prematurely. If you haven’t changed your filter recently, this should be your first physical check. Pro tip: Most filters should be replaced every 1–3 months during heavy use.
3. Look for Vent & Register Blockages
Make sure all vents and returns are open and unobstructed. Furniture, rugs, or toys can block airflow and cause inefficient heating even when the furnace itself is operating.
4. Pilot and Ignition Components
To troubleshoot gas furnaces:
- Older units may have a pilot light that can be relit (per manufacturer instructions)
- Newer units use an electronic igniter or hot surface ignition
- If the pilot won’t stay lit or the igniter malfunctions, the burners won’t ignite. Cleaning a flame sensor softly can help, but many ignition issues require a professional HVAC technician.
5. Blower and Electrical Components
If the furnace seems to run but no warm air is delivered, electrical or blower issues may be involved. Problems such as:
- Loose wiring
- Failed capacitors
- Blower motor faults
- They are usually beyond basic DIY fixes and best left to a licensed professional.
6. Gas and Fuel Supply Checks
If you have a gas furnace:
- Confirm other gas appliances are working
- Ensure the gas valve is open
- A disrupted fuel supply stops heating before anything else. Handling gas systems often requires HVAC training due to safety risks.
When to Stop DIY & Call a Technician
While basic checks can help you rule out simple issues, complex furnace problems. Especially those involving electrical controls, ignition, or fuel should be diagnosed and repaired by a trained HVAC professional. Signs you should call a technician include:
- No heat after filter and thermostat checks
- Strange noises or burning smells
- Frequent cycling on and off
- Furnace starts but shuts down quickly
- Getting professional help ensures safe, reliable furnace operation and avoids potential hazards. Schedule a HVAC service with High Tech Heating & Cooling by giving us a call at (215) 486-0879.
