Troubleshooting Pilot Light Problems in Gas Water Heating


If your pilot light goes out, you may be able to fix the problem yourself. Follow these steps to troubleshoot a pilot light that won’t stay lit. But you need to be very careful when working with gas. If you’re not comfortable doing this work, it’s best to call a professional.

Troubleshooting Pilot Light Problems in Gas Water Heating

At All American Plumbing, Heating, & Air, we are experts in pilot light repair and other gas heating issues. Call us today if you need help with your pilot light or any other plumbing, heating, or cooling issue.

What is a Pilot Light And How Does it Work?

A pilot light is a small flame that ignites the gas emanating from the gas valve and the main burner. The pilot light is commonly seen in water heaters, fireplaces, and older or low-cost furnaces.

Your unit’s pilot light is always burning when the unit is on. If the pilot light goes out, the gas will stop flowing and your unit will shut off. When heating is required, the gas control valve releases the gas into the main burner where the pilot light ignites the gas.

Apart from lighting the main burner, the pilot light also provides warmth to the thermocouple. This heat creates electricity that holds the electromagnetic valve within the gas control valve open for the gas to flow. When the pilot light is blown or absent, the thermocouple’s tip cools, and the electricity is cut off, the gas valve is shut, which then shuts off the unit. All gas appliances have this kind of feature for safety reasons. It prevents gas from leaking inside your home.

Although the pilot is generally used because it is durable and works, it does have one main disadvantage. It wastes energy because it is constantly burning, even when the appliance is not in use.

If you do not want problems with your water heater pilot light, you should study the manufacturer’s manual, especially how to light the pilot and how to maintain the gas water heater.

If not, when the pilot light doesn’t work correctly, the unit will fail to work and your home won’t get hot water. Recall that the majority of cheaper and older gas water heaters have pilot lights, while the more expensive and newer models have piezoelectric sparks or a hot surface lighter which happens to be more reliable and sturdy.

Fixing a pilot light is not complicated, and you can probably do it yourself. But if you don’t feel comfortable working with gas, or you lack the necessary skills or equipment, it’s best to call a professional plumber.

Visual Inspection

By visually inspecting the pilot flame, you can tell if the pilot light is working correctly or not.

  • A healthy pilot light should be blue. If the pilot light is blue, that means it’s burning hot enough. It should not burn with a yellow or red flame.
  • A flickering or wavering flame indicates that the pilot isn’t burning at the right temperature. This can be caused by a draft, dirt, or other factors.
  • The dirt present in the tube gives rise to a split flame.
  • A yellow flame is an indication of insufficient airflow, dirty pilot tube, or incomplete gas combustion.

Causes, Problems, And Troubleshooting Pilot Light Tips

The Pilot Light Goes Out Due to Condensation

Most modern energy efficient water heaters produce condensation on the outside of the tank. When this happens, some of the water drips down and gets into the pilot light tube. This can extinguish the pilot light.

The condensation may occur when you switch on the water heater for the first time or if you have an undersized heater and the water coming in is extremely cold. It may also occur because your energy efficient water heater creates flu gases at lower temperature.

The Light Goes Out Due to Improper Venting or Air Supply

Your water heater needs a proper air supply for the pilot light to stay lit. If there is not enough air, the pilot light will go out. This mostly happens in direct vent gas water heaters (DV). The most common cause of this problem is the draft near the unit’s base. Other possibilities are high winds or down drafts from the fan.

If there’s airflow reduction, find the source of the problem and correct it. If you have a DV water heater, make sure that the vent isn’t blocked. If your water heater was installed in the attic, too much heat (more than 250 F) could also be a cause. It also helps to seal any gaps or holes in the walls or weather strip windows and doors to prevent drafts.

The Pilot Does Not Light

If your pilot light does not light, the burner will not ignite, and you won’t get hot water. Here are some of the causes:

  • The wire connection is not secure.
  • There is no gas supply to the unit. This may be due to a faulty gas valve.
  • The pilot line is blocked. Clean it or change it.
  • The thermocouple is defective.
  • Replace the electrode if it’s broken.
  • Soot or carbon deposits have built up on the pilot light. Clean it with a dry cloth and sand paper.

The Pilot Light Won’t Stay Lit

You should realize that there are usually many reasons for this problem. The most common reasons are:

  • The pilot light tube is dirty. Clean it with a dry cloth and sandpaper.
  • There is no gas or not enough gas flowing to the pilot light. This may be due to a leaky gas valve or a problem from the gas company.
  • The thermocouple is defective. Replace it.
  • Air in the gas line can stop the pilot light from lighting. If you suspect that it’s the cause of the problem, call a professional to expel the air in the gas line.
  • If the thermostat ECO switch is open, replace the thermostat.
  • The gas valve and the internal elements are not working. Replace the entire gas control valve.
  • Is the thermocouple connection loose? You should tighten it.

The Pilot Flame is Too Large

The pilot flame is usually too large because there is too much gas flowing into the pilot light (high gas pressure). This could be because of a problem with the gas company. If you suspect that it’s the cause of the problem, contact the gas company.

Check the pilot burner orifice to ensure it’s the correct size. There have also been stories from some homeowners that during cleaning, a tiny orifice cap drops from the top of the pilot tube and makes the pilot light very high, yellow, and unstable.

The Pilot Flame is Too Small

Low gas pressure can also cause the pilot light to be too small. You should find out from the gas company if they are supplying the right amount of gas. If so, then the problem lies with your water heater. A clogged pilot light tube may also be responsible for this problem. The clog may occur as a result of dirt from the gas line. Contact your utility company and get a gas technician to install a dirt trap in your gas line.

If the pilot burner in your unit is not the right one, you could end up with a pilot light that’s too small. The burner orifice should be the right size for your unit. Check the manufacturer’s instructions to find out what size it should be.

Before you troubleshoot the plot light, remember that it is always on and the flame needs to be blue. Adjust it if it’s yellow. You should make sure that the tank is full of water before you light the pilot light.

Contact Us if You Can’t Figure Out What’s Causing The Problem

If you can’t figure out what’s causing your pilot light problem, or if you’re not comfortable troubleshooting it, please contact All American Plumbing, Heating, & Air. We have a team of qualified and experienced technicians who will be more than happy to help you. We’ll come to your home or business and take a look at your water heater. We’ll find the problem and fix it quickly and efficiently. Schedule an appointment with us today by calling (209) 710-5629.