Furnace Not Working? Here's How To Easily Restart It in 3 Steps
Has your furnace suddenly stopped blowing hot air? Before you panic or call a professional, try restarting it. A simple reset can get your furnace going again in minutes. By following a few easy DIY steps to restart the furnace, you can save money and avoid freezing temperatures.
With a basic understanding of your furnace's components and a bit of troubleshooting, you can often resolve furnace problems yourself. We'll cover everything from locating the pilot light to flipping breakers so you can get your heat back on quickly.
Furnace Issues and Troubleshooting
Furnaces stop working for a variety of reasons. Here are some of the most common furnace problems that require a system restart:
- Power outages
- The pilot light goes out
- The burners fail to ignite
- The blower stops circulating air
- The furnace starts blowing cold air
Before arranging costly HVAC repairs, it's worth trying to restart your unit. Resetting the furnace essentially involves turning the system off, allowing time to reset internal components, then turning it back on. This simple process will resolve many basic problems.
To restart a furnace, you'll need to locate its key components like the circuit breaker, pilot light, gas valve, and thermostat. Let's start by shutting off power to the furnace's heating system.
Step 1: Shut Off Power Supply
We'll begin by cutting power to the furnace so internal parts can fully reset. This requires locating your home's main circuit breaker box.
Locate Home's Circuit Breaker
The main electrical panel or breaker box is typically located in the basement, garage, utility room, or a closet. It's a large grey metal box with many switches marked for different circuits.
Scan the text on the circuit breakers to identify the one connected to your furnace. There may be a label indicating the furnace or HVAC system. The correct breaker switch should be clearly marked.
Flip Main Breaker Off
Once you've located the furnace's circuit breaker, flip the switch to the "Off" position. If it's currently "On", switching it off cuts power to the furnace.
Leave the circuit breaker off for 2-3 minutes. This brief power cutoff will reset many furnace components and computer boards. Now we can restart the system.
Step 2: Restart Ignition System
Next, we'll restart your furnace's ignition system to relight the pilot and burners. The exact steps depend on your furnace type and ignition source:
- Older models use a standing pilot light requiring manual lighting
- Newer furnaces have an electronic igniter that sparks automatically
Refer to your furnace manual to confirm which system you have. We'll review the restart procedures for both.
Locate and Relight Pilot Light
On older furnace units, find the small pilot light tube near the gas burners. It contains a small flame used to ignite the furnace. When relighting the furnace pilot:
- Use the gas valve to cut gas flow to the unit. Look for a valve handle or dial on or near the furnace.
- After turning the gas off, wait 5 minutes to prevent a gas buildup then smell for gas. If you detect gas, don't relight until the leak is fixed.
- Insert a long lighter wand or burning match next to the pilot light tube. Trigger sparking until you see a flame ignite.
- Continue holding it an additional 30 seconds for the safety thermocouple to sense the pilot is lit and allow gas flow to the burners.
- Finally, turn the gas valve back on so it remains lit.
The furnace pilot light should now remain burning. Next, we'll complete the restart by turning the power back on.
Reset Ignition on Newer Models
If you have a newer electronic ignition furnace, there's no pilot light. Instead, an electric igniter automatically sparks to start furnace flames. To restart this ignition sequence:
- Locate small ignition rod or igniter probe near the gas burner.
- Reset the furnace control board by switching the electric power off/on at the circuit breaker as we did initially.
- The electronic igniter will begin emitting sparks to reignite the gas burners once power returns.
After completing these ignition reset steps, we can send power back to the blower motor and other electrical components.
Step 3: Restore Power
Now that you've successfully restarted the ignition process and relit the pilot light or electronic sparking mechanism, we can send electricity back to the furnace by flipping the circuit breaker back on.
Flip Circuit Breaker Back On
Return to your breaker box, locate the circuit breaker powering the furnace, and flip it into the "On" position. Switching it on will restore power throughout the furnace system.
Listen for any humming from the blower fan restarting or click sounds from the gas valve opening. These noises confirm power is flowing properly again.
Check Thermostat
Finally, walk over to examine your thermostat settings. When power returns you may need to:
- Adjust temperature setting back to the desired heat point
- Switch from "Fan" mode back to "Heat"
- Allow 5-10 minutes for warm air blow throughout ducts
Set your thermostat correctly and give your newly restarted furnace a few minutes to resume heating. The fan should begin circulating warm air through vents indicating smooth operation. Enjoy that cozy heat!
Troubleshooting Issues
In some cases, your furnace may still not start even after completing the restart steps above. Here are some troubleshooting tips before calling a technician:
Furnace Still Not Working Properly
If warm air fails to resume after 10-15 minutes, recheck each previous step before arranging repairs:
- Confirm the circuit breaker didn't trip off again
- Verify pilot relit or electronic igniter is sparking properly
- Adjust thermostat to correct operating mode and temperature
- Try the furnace reset steps again from the beginning
Allow sufficient time for the system restart between attempts. You can retry the process multiple times before requiring a professional's assistance.
While an DIY reboot often fixes basic furnace issues, other problems require an HVAC technician's diagnosis and repair:
- Strange smells or sounds may indicate dangerous gas/exhaust leaks
- Pilot frequently goes out can signal problems sensing the pilot flame
- Blowing cold air may mean the heat exchanger needs replacement
- Error code lights signify complex internal issues
Damage from power surges or worn components could require repair by a heating and cooling specialist. Schedule professional service if problems persist beyond a standard restart.
By following these 3 simple furnace restart steps, you can restore heating operation yourself without waiting days for a service appointment. Locate the key components, shutdown power briefly, restart the ignition sequence, flip the breaker back on, and validate normal functionality returns. With this basic troubleshooting approach, you can keep your home warm and avoid paying for an unnecessary service call.