Why does my gas heater keep flickering?

Author: Lennie Zemlak  |  Last update: Wednesday, October 15, 2025

A flickering flame in a furnace typically indicates a potential malfunction within the heating system. This can be caused by a variety of issues ranging from minor concerns like a dirty burner to more severe problems like a malfunctioning gas valve or improper venting.

Why is the flame flickering on my gas heater?

Flame flickers or spits – A draft in the room can cause your flame to flicker. Spitting is often caused by a dirty gas orifice or tube. These can be cleaned with a stiff wire, but you'll need to remove the pilot light assembly to do so.

Why does my gas range keep flickering?

Your gas cooktop's flames may be flickering because your cooktop is exposed to a degree of natural air flow. Make sure your cooktop isn't exposed to wind or sudden changes in air flow in your kitchen. Gas cooktops differ in the gas supply they use.

What is a common problem for gas heaters?

Possible causes include a broken thermostat; the thermostat being set too low; an out pilot light; a blown fuse or circuit breaker; a closed gas valve; or electronic ignition problems.

Why does my heater keep flashing?

An error with the gas, ignition failure, or flame can cause the red light to start blinking. This could be an indication that your flame sensor is dirty, and/or could also mean there is a problem with the gas valve or ignitors.

Ventless Gas Heater Keeps Going Out, Gas Heater Won't Stay Lit-5 Minute fix every time.

Why is my furnace light blinking continuously?

A slow green light blinking may mean there is simply no call for heat, while a faster green furnace light blinking continuously means the furnace is in active heating mode. You should not take the front panel off while your furnace is running.

Why is the pilot light flickering on my gas heater?

If this occurs, adjust the flame using the screw on the pilot by following the instructions on your manual. Flickering flames can be caused by air drafts. Establish where the draft is coming from, and then seal it to protect your furnace. Spitting motion is caused by dirt in furnace tubes.

How do you know if your gas heater is going out?

Here is how to tell if your gas furnace is reaching the end of its road:
  • Increasing illnesses.
  • High furnace age.
  • High and unexplained utility bills.
  • Sudden troublesome noises.
  • Pilot flame color.
  • Dry air.
  • Soot.
  • Frequent repairs.

How much does it cost to replace a gas heater?

Gas furnaces costs can range from as little as $3,800 for a basic unit with installation to more than $10,000 to $12,000 for a high-efficiency model with professional installation.

What does flickering gas light mean?

The light flashes when you are going low on fuel (1 gallon left IIRC), and a solid light means get fuel now (1/2 gallon left). Now, if you have a full tank (i.e. > 1 gallon), and it is still flashing, the problem is most likely a stuck tank level float.

Why does my gas igniter keep clicking?

Check for food debris and blockage

Food remnants and debris can obstruct the igniter from sparking, which could lead to a clicking noise without ignition. Ensure that the area around the igniter is clean and dry before trying again. Our guide on cleaning the gas hob can be found here.

How do you know if your gas stove is dying?

Signs that your gas stove is not working properly include smelling gas, the burners not lighting, strange noises, poor temperature control, or the flame color changing to red, yellow, or orange rather than blue.

Why is my furnace fluttering?

Several factors can contribute to a flickering or wavering furnace flame: Airflow Issues: One common cause of flame flickering is turbulent airflow within the furnace. This can be due to a dirty air filter restricting the flow of air, blocked vents, or even the incorrect installation of ductwork.

How do you stop a flame from flickering?

Generally candle flames flicker as there is too little, or too much, air reaching the flame; moving air disturbs the candles flame causing smoke. To prevent this, always burn your candles in well ventilated rooms, away from drafts or strong air currents.

How do I know if my heater igniter is bad?

If you notice your home getting colder and colder, yet the Furnace never comes on, no matter how high you set the temperature, this could indicate a problem with the ignitor.

How do you know if your furnace needs to be reset?

Why Your Furnace May Need To Be Reset
  1. The furnace has overheated: When your furnace runs too hot, it triggers a safety shut-off to prevent damage. ...
  2. The fuel supply is empty: Your furnace can't generate heat without fuel. ...
  3. The gas valve is shut: A closed valve blocks the fuel supply.

How long to leave furnace off to reset?

Leave the breaker(s) off for at least 10 minutes while the system is off and “rebooting.” After 10 minutes have elapsed, go back to the breaker box and flip the HVAC breaker(s) back on.

Why is my gas heater not working in my house?

Check to make sure power to the furnace is on.

There's a power disconnect switch by the furnace, even gas systems use electricity. Check the fuse/circuit breaker at the electrical panel for the furnace to make sure the breaker has not tripped. Make sure the power switch next to the furnace is in the “On” “position.

How do you know when the gas heater needs to be replaced?

8 Telltale Signs Its Time To Replace Your Furnace
  1. The Age of Your System. ...
  2. Rising Energy Bills. ...
  3. Excessive Dust, Dirt, Soot or Rust Particles. ...
  4. Home Humidity Problems. ...
  5. Rooms are Heating Unevenly. ...
  6. Furnace Becomes Unusually Noisy or Develops Rattles, Buzzes or Hums. ...
  7. Furnace Has Visible Signs of Rust or Cracks in or Around System.

How long will a gas heater last?

For a medium-sized portable gas heater, a 15kg bottle can last approximately 50 to 60 hours when used on a medium setting. This estimate assumes the heater is operated for about 3 to 4 hours daily, translating to roughly two weeks of usage.

Why is my pilot flickering?

The pilot light flame is weak or flickering

There are two main causes for a weak or flickering flame — dirt and airflow. Dirt in the tube can obstruct gas flow and cause the flame to flicker or weaken. Poor airflow starves the flame of oxygen, causing it to sputter and flicker as it tries to stay alive.

How do I know if my gas furnace pilot light is out?

This is something you can easily check by looking at your furnace to see if you see a constant flame even when it is not currently running. You can also open the access door to look for a pilot control knob. If you don't see a control knob or a flame, it means that your furnace doesn't have a standing pilot light.

Can furnace cause lights to flicker?

If you've noticed that your power flickers when the heat comes on, you may have a severe issue. It's a good idea to contact an HVAC professional right away to inspect and repair your furnace. If you frequently have flickering lights when you turn the furnace on, it could indicate an electrical problem or other concern.

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