7 Reasons A Water Heater Pilot Light Won’t Stay Lit

Showering early in the morning is associated with cold, chilly water to most people. Luckily, water heaters are here to rescue us from the cold! This device helps bring warm water into your shower.


The most common reasons a water heater pilot light won’t stay lit & keeps going out are insufficient combustible air & issues with the thermocouple.

In this article, we’ll also look at the following topics:

  • Issues with a Honeywell
  • Dealing with wind

Continue reading

Within a few months from installation, perhaps your unit breaks down, leaving you frustrated and disappointed. Do you think it is normal for it to die on you? Does it happen to several users, or is it an isolated case to some?

The short answer is no. It should last for several years! Several manufacturers claim their products will last at least ten years without major issues occurring.

There is probably a reason or two for it to die out on you. This article talks about all the possible reasons for the pilot light to turn off, effectively rendering your heater useless. 

water heater

Table of Contents

Reasons A Water Heater Pilot Light Won’t Stay Lit

There are two possible explanations for this issue. You can either have one or both happening concurrently. Here are the reasons a water heater pilot light won’t stay lit and keeps going out.

Insufficient combustible air

The lack of combustible air can cause the pilot light to go out. The heater needs air to keep it burning. If it does not get enough supply, the fire will go out. Check and ensure the surroundings of the heater are free from:

  • lint
  • clutter
  • and debris.

Keeping it clean and free from these artifacts increases airflow.

Issues with the thermocouple

Richmond water heater

Thermocouple malfunction may happen over time, especially during extensive use. It can also accumulate dust. When it happens, the thermocouple is unable to sense the pilot light. The gas supply stops, and the fire goes out.

The light keeps going out every few days

Here are seven reasons why the water heater pilot is intermittently going out.

1. Debris or dirt in the pilot tube

  • Several heaters have problems with the tube’s cleanliness. In most cases, the issue is because of dirt build-up, which happens over time.
  • The tube is responsible for supplying gas, which it needs for combustion. A clogged one may cause the flame to go out unexpectedly.
  • The only solution is to clean the tube. An ultra-thin needle should help you do it. This step takes patience, especially the ones that are very dirty. You can put it back after you finish cleaning. The blame should be steady this time. 

2. Filthy thermocouple

  • The thermocouple serves as the central unit of the entire heater. It triggers the delivery of electric current, and it closes the valve. It also prevents gas leaks from spreading.
  • A dirty thermocouple may interfere with its duties. For example, thick debris may stop electric current from reaching its destination.
  • The solution to this is again cleaning. Turn off the gas valve and wait until the thermocouple cools off. Scrub it using fine sandpaper. 

3. Twisted or curved thermocouple

  • After cleaning your filthy thermocouple, check if it is in the correct position. We also recommend checking for bent or twisted signs. Its ideal placement is near the pilot light, where it receives heat.
  • What happens if it is too far? It will not effectively receive heat, so it cannot produce an electric current. It will conclude the pilot light is off and will close the valve.
  • Fixing this issue involves cutting off the supply to the gas. Next, turn off the heater and wait for the unit to cool off, which takes a few minutes only. A kinked or twisted thermocouple requires manual straightening. Remember, it needs to have in close contact with the pilot light.

4. Broken thermocouple

  • If the problem still occurs, your thermocouple is likely broken. Before replacing it, use a multimeter to do a diagnostic test.
  • A voltage supply of less than 20 MV means it is useless. A replacement is the only fix.
Electric Water Heater

5. Issues with the flex tube

  • The flex tube connects the burner to the gas controller. The burner houses the thermocouple and pilot light.
  • A clogged or broken flex tube hinders the gas supply to the burner.
  • A flex tube issue is uncommon compared to a thermocouple issue.
  • Look for damages in the flex tube. Get a replacement if you see the damage.

6. Defective main control valve

  • The main control valve rarely gets defective.
  • If you do not see issues with the flex tube, pilot tube, or thermocouple, the fault is likely with the main control valve.
  • A faulty control valve randomly closes the valve, cutting the gas supply and leading to a flickering flame.
  • The signs of a faulty unit include a malfunctioning control know, a button that does not pop up, and inaccurate water temperature.
  • We recommend replacing the main control valve instead of repairing it. Some technicians may claim they can fix it, but we recommend avoiding that altogether and getting a replacement instead. 

7. Electrical wiring issues

  • Most electric water heaters encounter this problem. 
  • Hire a licensed technician with a good track record. These technicians should be able to correctly and neatly route your electrical wiring.
  • Random shutdowns are a sign of electrical wiring issues. Switch off your unit and call a technician right away if this happens. 

Here is a step-by-step guide on how to do it. Most people can do it without requesting professional help. 

How to light the pilot light on your water heater?

  1. Turn off the gas and wait at least ten minutes before proceeding to the next step.

    Give time for gas in the surrounding area to clear out because it is highly flammable. 

  2. Access the pilot light, which you will find beneath the gas valve.

    Most manufacturers cover it with a door. We recommend using a flashlight because this area may be particularly dark.

  3. Set the gas valve to “Pilot” and press it down.

    This action supplies gas to the valve.

  4. Ignite the pilot.

    You may not need manual lighting for gas water heaters manufactured in the past eight to nine years. These have a spark generator. Use a long lighter if you do not see an ignition button.

  5. After igniting the pilot light, turn on the gas.

Do not hesitate to call a professional technician if you need professional help. Most providers will charge a service fee for offering their services. 

The light is lit, but the burners won’t ignite

We recommend considering getting a replacement if your water heater system is old. Most newer models do not use a pilot light anymore. However, you can troubleshoot your current unit to see what is wrong.

The following three reasons may explain why your burner will not ignite.

  1. A faulty gas valve – A defective gas valve is the number one reason for the burner not igniting. The problem lies in the communication between the valve and the pilot.
  2. A defective thermocouple – A damaged thermocouple cannot detect or sense the flame. It happens if the thermocouple is rusty, which is common in outdated systems.  
  3. Automatic shut-off failure – Failure to shut off automatically is a sign of an issue. It translates to the burner not igniting even if the pilot is burning. 

It won’t stay lit after replacing the thermocouple.

Your gas control valve is likely faulty if it does not remain lit after a thermocouple replacement. You may also be experiencing a faulty thermal switch. We recommend consulting a licensed technician for the appropriate action. If you have a Whirlpool water heater, we recommend contacting a Whirlpool-authorized service center. 

Honeywell Codes

The following are the common status light codes for a Honeywell water heater.

One flash

One blink every three seconds signifies a normal operation, meaning no corrective action is required on your end. The unit will exhibit the same behavior in idle mode.

Two flashes

A low thermocouple voltage or an off-main valve flashes the indicator two every three seconds. Turning on the gas valve will likely address this issue. 

Three flashes

Three consecutive flashes every three seconds exhibit a malfunction in at least one of these parts:

  • Draft pressure switch
  • Condensate drainage system
  • Exhaust piping

Inspect for any piping blockage. Detaching each section should make it easier for you. Using a vent-cleaning brush will help release blockage from these parts. However, contacting a licensed professional is your best option because it involves electrical parts. 

Four flashes

Your unit is about to go to high-temperature shutdown mode if it exhibits four flashes every three seconds. Shut off your heater and wait for at least five to ten minutes before switching it on again. 

Five flashes

Five consecutive flashes every three seconds indicate a failed temperature sensor. Wiring issues and overheating are the culprits behind a bad temperature sensor.

Turn off the entire unit and measure the temperature using a multimeter. Set the multimeter to Ohms before attaching one probe to the center hole and the other to the outside. The resistance reading is the water temperature. 

Six flashes

Six flashes translate to a faulty burner. The first step is to check for leaks within the tank. Fix it if you find anything. The second step is to inspect the burner and replace it. Ensure detaching everything before starting the disassembly process. 

Seven flashes

Seven consecutive flashes after three seconds indicate electric failure. Repair the gas valve or the electric issue to reset the flashing LED.

Eight flashes

The flammable vapor sensor (FVS) is at fault if the LED flashes eight times. The following are common reasons for a defective flammable vapor:

  • Fault gas control
  • The FVS’ resistance goes beyond the range
  • Bad FVS wiring

The water heater pilot goes out after turning the temp control dial.

40 gal. LP water heater

If you experience this issue, we recommend replacing the thermocouple. There are several reasons for a defective thermocouple, which we covered in the previous sections.

You will likely encounter this issue as soon as the pilot light ignites and after releasing the control knob. 

Lack of hot waterThe water heater’s thermostat is not set high enough. Maybe the heating element is damaged.
Leaking waterThe water heater’s tank or connections are damaged or loose.
No power to the water heaterThe water heater’s circuit breaker or fuse has tripped. Maybe the power supply has been cut off.
Rumbling or popping noiseSediment has built up in the water heater’s tank and is heating and expanding.
Rusty waterThe water heater’s tank is corroded.
Big water heater manufacturersHeadquarters
A. O. SmithAshland City, TN, USA
Bradford WhiteAmbler, PA, USA
RheemAtlanta, GA, USA
GE AppliancesLouisville, KY, USA

What is a pilot light & its purpose?

We mentioned this term in the earlier section, but some may not know it. Those who had issues with their gas-powered appliances may be familiar with or have encountered them.

In the simplest terms, appliances utilize it to ignite the gas and run the device. The most common devices using it are:

  • a gas fireplace
  • furnace
  • and water heater.

Several manufacturers use liquefied petroleum or natural gas. However, certain companies may opt for other types as they see fit.

Many commercial kitchens rely on it for:

  • grills
  • burners
  • and ovens.

However, several residential systems use electrical ignition. George Layer and Conrad Shuck Jr. patented the safety gas-control system in the United States last May 13, 1922.

Occasionally, the term also refers to the LED indicator in an appliance, showing it is receiving electrical power and is ready to operate. Early applications use neon or incandescent lamps, but modern ones utilize LEDs. 

How do they work?

The previous section discusses the what. This section digs deeper into how it works. Heaters and furnaces usually use natural gas. Somewhere within these, you will find a small blue flame. The small blue flame is otherwise called the pilot light.

How does it work? The idea or principle behind it is simple. Gas flows through the main burner. The pilot serves as the ignition, providing flame to the gas flowing from the burner. The valve opens and releases gas when you switch on your furnace or water heater.

water heaters

The next question most people might ask is, “how do manufacturers create it?” A small tube from the gas pipe allows a small quantity of gas to pass through it. It continuously burns when you ignite the gas coming from it.

However, there is a safety concern involving this process. If the flame blows off, the gas may potentially spread through areas it should not. It will create an explosion if it collects inside your house and ignites a fire. How did manufacturers safely prevent this issue from happening? The tube has a valve, which cuts the gas supply if it blows out.

The valve is an interesting part of the mechanism. For one, it should sense if the pilot light is burning. At the same time, it should be able to do it without help from external electricity sources. A thermocouple is an answer to it, which generates electricity as it heats up by taking advantage of the electrical effects between metals.

For example, let us take one copper wire and two iron wires. Twist together one end of the iron wires and one end of the copper wires. Repeat the same procedure on the other end. Heat one end with fire and attach the other end to a voltmeter. You should see a reading greater than zero, signifying electrical presence.

The same principle applies to a thermocouple. One end of the junction sits on the flame. The electricity generates runs through the valves, holding them open. If it blows out, the thermocouple cools off and stops the electricity from flowing. It effectively closes the valve. Relighting involves manually pushing a button. 

How to check the light

At some point, you need to check the pilot light on your water heater. Your water will be cold if it is not burning. You can visually inspect the flame. However, the gas control valve can indicate if there is an issue. You can find the chamber door to the burner below the control valve.

The following are signs it has gone out:

  • Error message or a blinking LED
  • Unable to see the flame
  • The running water is cold

Aside from residential or commercial applications, water heaters are also available in an RV. Checking its status is similar.

bradford white water heater

It is blinking.

You must pay attention to flashing or blinking lights because it indicates something needs your attention. It speaks for the health of your heater, so knowing how to interpret it goes a long way.

There are several brands in the market. To name a few, some famous ones are:

  • Rheem Gladiator
  • Bradford White
  • Richmond
  • and Suburban Pilot 

Red Blinking Light

A red blinking light that flashes once every three seconds indicates everything is normal. In other words, the valve and the pilot light are functional.

However, it can also flash red if the flame sensor has accumulated rust flakes or has started corrosion. You can solve most rust issues by cleaning the rod with sandpaper. We recommend referring to the owner’s manual for more details. 

Green Blinking Light

A solid green LED indicates the unit is in standby mode and the water is hot. What about a green blinking LED?

  • One flash means the heater does not have enough water, so you must fill it.
  • Two blinks indicate it is shutting down because of extreme water temperature.
  • Three blinks indicate a compromise in the thermistor’s operations. Solving this issue involves ensuring the thermistor plug is snug and secure.
  • Four blinks indicate an issue with the upper element. It is the same case with five flashes.
  • Finally, six green flashes mean an issue with the control board. Problems with it cause the unit to lock out. 
Electric Water Heater Tank 30 Gal

Blue Blinking Light

Blue blinking light can mean several things because of its dependence on the maker and model.

  • An error in the draft pressure switch
  • Blockage in the diameter vacuum tubing
  • The pressure switch is defective
  • The diameter vacuum tubing contains water

Three blinks mean an open draft pressure switch. The possible causes are a blocked exhaust vent or a weak fan. 

Seven blinks indicate a fault flammable vapor sensor. Lastly, eight blinks mean that the sensor and thermostat well are unplugged or defective. 

White Blinking Light

The pilot light is out or is not burning. As a result, the water will be cold.

How to stop the wind from blowing it out

You can prevent this issue from happening by fixing the following components:

  • Gas release
  • Thermocouple

We also recommend checking the firebox, shielding against downdrafts, and adding a roof to the chimney. 

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