Nothing’s worse than waking up on a cold morning and realizing your furnace won’t turn on. Before you panic or bundle up in layers, take a few minutes to run through these simple steps. You might be able to get your system running again without needing to call a technician.
This guide from Affordable Comfort will help you safely troubleshoot the most common reasons your furnace refuses to start—and when it’s time to bring in a professional.
Step 1: Check the Thermostat
Sometimes the issue isn’t with the furnace at all.
- Make sure your thermostat is set to “Heat.”
- Increase the temperature at least 5 degrees above the current room temp.
- Check if the display is lit. If not, replace the batteries or check for power.
Step 2: Inspect the Power Supply
Furnaces require electricity to run—even gas models.
- Locate your home’s breaker panel and look for a tripped furnace switch.
- Reset any tripped breakers and test again.
- If there’s a dedicated power switch near the furnace, make sure it’s turned on.
Step 3: Ensure the Furnace Door Is Secure
Many furnaces have a safety switch that disables operation when the access panel is open.
- Open the panel and close it securely.
- Listen for a click that indicates the door switch engaged.
Step 4: Check the Air Filter
A dirty filter can restrict airflow and cause the system to overheat and shut down.
- Locate the air filter (usually near the return duct or blower).
- If it looks clogged, replace it with a clean one.
Step 5: Look at the Pilot Light or Ignition
- For older systems: Check if the pilot light is out. If so, follow your manufacturer’s instructions to relight it.
- For modern systems: Make sure the electronic ignition system is functioning (you may need to listen for clicking or see if a light is blinking).
Step 6: Check for Error Codes
- Many modern furnaces have a small LED light behind a small panel.
- Count the blinks and compare with the code chart (often found inside the panel door).
- This can point to specific issues like pressure switches, flame sensors, or limit switches.
When to Call in a Professional
If you’ve run through all of these steps and your furnace still won’t start, it’s time to call the experts. You may be dealing with:
- A failed blower motor
- A faulty ignitor
- A malfunctioning control board
Affordable Comfort’s certified technicians can diagnose and fix the issue quickly—often the same day you call.
Prevent It Next Time
The best way to avoid a cold surprise is with regular furnace maintenance. We recommend scheduling a tune-up each fall before the heating season begins. It’s a small investment that helps prevent costly breakdowns.
Need Fast Furnace Repair? We’re here to help. Contact Affordable Comfort today for reliable, local service that gets your heat back on—fast.
