If your furnace isn't turning on, first check that the thermostat is set to "Heat" and its batteries are fresh. Then, verify the dedicated furnace switch (often a light switch near the unit) is toggled on, and reset the HVAC circuit breaker at your home's main panel.
Resetting a furnace igniter usually involves performing a power cycle to clear a system lockout, though some electric models have a physical high-limit reset button. If the igniter is cracked or covered in carbon buildup, it will need to be inspected and potentially cleaned or replaced.
To get your furnace to kick on, first verify your thermostat is set to "Heat" and raised at least 5 degrees above room temperature. Next, check that the furnace power switch (usually resembling a standard light switch on or near the unit) is toggled "ON".
Ignition or Pilot Light Problems: Older furnaces rely on a pilot light that can blow out. Modern systems use electronic igniters—if these crack or fail, gas will not ignite. Gas Supply Issues: A closed gas valve or utility interruption will prevent the furnace from producing heat.
If your heater is running but not producing heat, it could be due to issues like a clogged air filter, dirty burners, pilot light or ignition failure, malfunctioning thermostat, or blown fuse. It may also be caused by gas supply problems or a faulty blower motor.
6 Reasons Why Your Furnace is Not Igniting
The reset button on a furnace is typically a small, raised red or yellow button, often labeled with an "R". You will most commonly find it inside the blower compartment, either directly on the side of the blower motor housing or on the main control panel.
To determine if your furnace ignitor is bad, look for visible cracks, listen for repeated clicking noises without a flame, or check for a bright orange glow during startup. To confirm a failure, you can test it using a multimeter set to measure resistance (Ohms).
How much does a furnace ignitor replacement cost? For a DIY repair, the part typically costs between $20 and $100. If you hire a professional, expect to pay between $150 and $350 for parts and labor.
Malfunctioning Thermostat
These problems could be easily remedied by either replacing your furnace's thermostat or calling a technician to come inspect it, as there might be other issues contributing to the furnace not igniting.
When your furnace clicks but refuses to turn on, it typically means the electronic ignition sequence has failed. This is often caused by a dirty flame sensor, a cracked or burnt-out igniter, or a faulty gas valve.
To determine if your furnace fuse is blown, turn off the power to the unit, remove the automotive-style fuse from the control board, and inspect it for a broken metal filament or dark burn marks. Alternatively, use a multimeter to check for electrical continuity.
Yes, you can manually light a gas furnace, but the exact method depends on whether it has an old-school standing pilot or a newer electronic ignition.
If resetting your electronic ignitor doesn't solve your furnace issue, you need to call a professional to look at it. Remember, you cannot light the electronic ignition manually. Contact an HVAC specialist at Sanks to diagnose and repair your furnace as soon as possible.
To reset your furnace, start by turning off the circuit breaker and furnace power, wait about 30 seconds to a minute, then turn the power back on. If your furnace uses gas, you may also need to turn off the gas for a few minutes before turning it back on.
The heat exchanger is often considered the most costly part of a furnace to repair or replace. It is a critical component that transfers heat from the combustion process to the air that circulates throughout your home. Over time, heat exchangers can crack due to the constant heating and cooling cycles they undergo.
A furnace ignitor typically lasts between 3 to 7 years. However, the exact lifespan largely depends on the material, your furnace's usage, and how well you maintain your system:
Disconnect and Remove the Old Ignitor: Unplug the wire connector for the ignitor and carefully unscrew the bracket holding it in place. Install the New Ignitor: Screw the new ignitor into place and connect the wiring. Safety Reminder: Never touch the gray or black part of the new ignitor with your bare hands.
Hot Surface Ignitors (HSI)
If your faulty furnace ignitor is an HSI, then there is no good way to repair it. You'll need your furnace brand, the model and serial number, and a few decent tools to replace it.
Without the ignitor, your heater won't blow hot air. It's a critical part of the furnace system since it is responsible for lighting the burner that starts the combustion process that turns fuel into heat. In older units, the furnace ignitor is a traditional pilot light.
To test a gas appliance (furnace or oven) igniter, either perform a continuity test (checks if the internal circuit is intact) or an amperage/voltage test (checks if it draws the correct power to ignite the gas).
The $5,000 rule is a guideline to help homeowners decide whether to repair or replace their HVAC system. You multiply the age of your unit by the cost of the needed repair. If that number exceeds $5,000, replacing your HVAC system is often more cost-effective.
If it doesn't start at all, you can press the button one more time. But, if you press the reset button and your furnace goes on and turns off again, don't press the button again. Continuing to press the reset button can damage your system. Doing so will pump more oil into the furnace and worsen any existing issues.
To get your furnace to kick on, first verify your thermostat is set to "Heat" and raised at least 5 degrees above room temperature. Next, check that the furnace power switch (usually resembling a standard light switch on or near the unit) is toggled "ON".
Stop repeatedly resetting: While resetting might temporarily bring the heat back, frequent shutdowns are a sign that something is wrong. Continuing to reset without diagnosing the issue can make the problem worse. Check the air filter: This is the most common reason for a furnace to overheat and shut down.