Reasons Hot Water Heater Pilot Light Won’t Stay Lit

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If you're used to bathing or doing other house chores with hot water, you won't like any damage to your gas water heaters. But things don't always turn out as you expect, and at times your water heater's pilot light isn't working as it should.

When your pilot light doesn't light up, you'll be dealing with a faulty water heater. Before you panic and call a technician, you need to find out the cause of the problem.

Maybe it could be an easy fix that only requires your DIY skills. Many reasons may cause your gas water heater pilot light to refuse to light up or light up but doesn't stay that way long enough. Here are some of the reasons that might cause the issue and how to make sure your pilot light stays lit.

Bad Thermocouple

A defective thermocouple may be one of the common reasons your water heater pilot light won't stay lit. If you're using a gas-fired water heater, you must know that they have a standing pilot that ignites the main burner.

The main gas valve supplies the fuel for the pilot assembly, and the thermocouple monitors this process. The thermocouple detects heat by generating a small voltage to ensure that gas flows to the water heater pilot light.

A bad thermocouple cannot sense the flame, which means the valve will not receive the voltage signal needed to enable the gas to move to the pilot assembly. Instead of lighting up, it will shut off the gas supplier as a safety precaution.

Dirty Thermocouple

Dirt particles can get in the way, interfering with the signal that the thermocouple gives. This misleads the thermocouple into believing the pilot is out and ends up shutting the gas supply to ensure safety.

You can easily fix this issue by cleaning the thermocouple. Before you start the cleaning, ensure the valve is off so it doesn't leak. You can then locate the thermocouple and clean it.

Bent Thermocouple

Another issue that may interfere with the functioning of the thermocouple is bent. The thermocouple can be bent to the point that it loses the heat signal coming from an electric current. If the thermocouple is curved too far from the pilot, it won't detect the heat signal; hence your water heater pilot light won't stay lit.

To fix this problem, you need to straighten up the thermocouple. Make sure it bends back towards the pilot so that the flame slightly touches it. Allow it to cool for at least five minutes before touching it to avoid burns. You can also use a safety device for this so you protect yourself.


Damaged Thermocouple

If you're dealing with a broken thermocouple, the chances are that your gas water heater won't light up. Unfortunately, most water heaters experience this problem from time to time. To confirm if you're dealing with a damaged thermocouple, remove it and use a multimeter to test the thermocouple.

Ensure the valve is off and allow the thermocouple to cool before attempting to remove it. Check if the voltage supply is below 20 MV. If that's the case, then you're dealing with a damaged thermocouple.

How to Fix It

For this issue, you need to get a qualified hot water heater technician to help you replace or repair the damaged thermocouple. Sometimes the problem may only need to be repaired if the damage is not too severe. For serious damage, don't attempt to replace the device by yourself as local regulations require a qualified technician to do the replacement work.

Dirty Pilot Tube

Your pilot tube collects dirt and debris over time, which can interfere with the gas flow due to blockage. When there's a blockage, the pilot won't get the needed fuel to stay lit. This problem may even prevent your water heater pilot light from lighting altogether. But you don't have to worry because fixing a dirty pilot tube is very easy.

How to Fix It

You need to slide a small needle to get access into the dirty pilot tube and remove any dirt and debris stuck in it. It might take you some time to clear the dirt depending on how dirty it way completely. To check if you've cleared the dirt, ignite the pilot and see if it lights up properly and stays lit.

Check the color of the flame and confirm if it's blue. If you're still dealing with an unlit pilot, that doesn't light up properly by producing a small flame, or you notice that the pilot flame isn't blue, remove the tube and clean it once more.

Kink in the Flex Tube

The flex tube is tasked with providing fuel through the gas controller. Over time, the tube gets kinked, and that interferes with the fuel flow. This is one of the most common reasons that cause your burner not to stay lit.

Sometimes, you may notice that the pilot is still working as it should, but your pilot light won't stay lit. If this is the case, then you can be sure that the problem is in your flex tube.

How to Fix It

The good news is that this is another easy-fix problem, and you should be able to rule it out early on. To fix it, look for any kinks in the tube and remove them. Then, straighten up the tube to ensure there is no obstruction in the flow.

You might also need to replace the tube if this doesn't fix the problem. But before resorting to changing the tube, be sure this is the problem because flex tube issues are less frequent.

A Problem in the Main Gas Control Valve

Another reason why your water heater pilot light won't light could be a faulty main control valve. If none of the above fixes troubleshoot the issue, the problem could be in the thermostatic control. This is often referred to as the control valve or gas valve.

While a gas control valve issue occurs less often, many people associate all their heater problems with this. Before you assume that this is a problem, you should first check other pilot light issues and determine if they're not the ones causing problems. One way to be sure that the problem may be in the main control is to use a multimeter to test.


How to Fix It

If you're sure that you have a faulty control valve, you need to get a technician to repair it. The best solution at this point is to change it. This will enable you to have a longer functional water heater and spare you from incurring any future cost of repairs.

Gas Burner Issues

Your hot water heater's burner is another essential component that needs to work correctly all the time. The burner is tasked with burning the natural gas that comes into the heater. If the gas burner is faulty, it may affect the pilot light.

It's not advisable to fix or replace it all by yourself. But you still need to troubleshoot to ensure it's the reason why your water heater pilot light won't stay lit.

How to Fix It

To fix it, turn on the hot water tap and let it run for at least five minutes. Listen carefully to the water heater if you can hear the sound of kicking. If you don't hear it ignite, you might be dealing with a faulty burner. Contact a professional to replace the damaged parts.

Check the Gas Valve and Supply

Finally, the reason why your pilot light won't stay lit could be because your supply is shut off. To confirm this, follow the fuel line from the heating unit to find the shut-off valve.

If the water heater label is indicated as ON, the lever will point to the gas line. If you find the lever is turned 90 degrees to the line, it means the fuel supply is turned OFF. Turn it on and restore your hot water.

Another reason that your pilot light isn't on is that there could be a gas outage in your area. There could be construction work going on, causing them to turn off the supply and gas pressure for safety reasons like gas leak prevention.

If you have another gas appliance in your home like a gas stove, verify to see if they're working before taking any action. You can also confirm with your neighbor if they're experiencing the same problem.

Like this water heater problem, unclogging the bathtub drain and fixing the low pressure in the kitchen faucet is also some of the plumbing issues that you can totally DIY.

Water Heater's Pilot Light: Bottom Line

There are many possible causes of why your water heater pilot light tube won't stay lit. Most of the pilot light issues may lead you to a simple solution that you can solve without the help of a professional. However, some problems may be more complex and will need professional expertise to solve. At other times, you may need to incur additional costs of buying a new water heater.

You need to take precautions when dealing with such issues because gas and electricity can be very dangerous, especially if you're inexperienced with the burner chamber or access panel. If you're not sure about what you're doing, don't attempt to troubleshoot, repair, or replace anything. You should have your technician just a phone call away in case of such issues. This protects you from leaking gas and damage to other gas appliances.

Dino Paccino

Dino Paccino

Dino is a lifelong writer and home improvement specialist. He enjoys bringing cutting-edge information on home renovation and remodeling to Kitchen Infinity.

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