26 Apr. 19

Why does the pilot light in my heater keep going out?


One of the most frustrating things is not having a water heater during cold months, or having a spoilt water heater. It is terrifying. The absence of a water heater in such periods exposes you to a cold which could even result in health problems. This is why the essence of a water heater, like many other household appliances, cannot be overemphasized.

Your water heater makes it important for you to enjoy the benefits of a good supply of hot water. These water heaters are almost always durable and hardly stop abruptly. The systems providing hot water are often reliable and can perform for years without having a problem. But, sometimes they can stop working suddenly, a situation which may be an inconvenience. When this happens, although you may not be able to fix it appropriately, good background of your heater and its work-mode will help you in troubleshooting.

One of the reasons why your water heater can suddenly stop working is a defective pilot light. When your pilot light goes out, it suddenly causes your water heater to stop working. If your pilot light refuses to stay lit, then it is essential that you fix it immediately. This is because without the pilot light lit, your water heater cannot work, and your water will not be warm.

Basic types of heaters and how they work

One of the significant steps towards grasping a sufficient background of your HVAC systems is to learn how it works. There are several types of water heaters with each of them having different features. A lot of homes have a tank kind of water heater. You own this kind of heater if your water heater has a large cylindrical tank standing on end with pipes connected to it. If this is not the case, it’s possible that your water is heated by a boiler, or that your water is heated by a tankless system working instantaneously.

Tank-type water heaters

Two things can power a tank-type water heater, and they are either electricity or fuel. For fuel type tank heaters, the most commonly used one is gas which could either be propane or natural gas. While fuel powered water heaters have a pipe for the purpose of passing out exhaust gases, electric heaters have a power cable that connects the heater to the electric panel. Tank-type heaters, however, do not run solely like other types of water heaters.

Your tank-type heaters run in two phases. It does not just supply hot water but also stores water until it is ready to use. As a result, apart from the heating system of the tank, the water heater also comes outfitted with an element of insulation which serves the purpose of keeping the water warm.

Some pipes serve the purpose of supply and delivery of water, and they are always found on the top of the tank. While the supply pipe carries cold water from the top to the bottom, the delivery pipe takes water from the top. For precautionary purposes, water heaters come with T&P valves which regulate the temperature and pressure level of the water heater. The valve works by opening when either the temperature or pressure goes beyond the safe limit. It should, however, be noted that the T&P valve should not be connected to the drain so that when the valve defectively opens, it can easily be noticed.

More often than not, these tanks are glass-lined on the inside to prevent the tanks from corroding. Corrosion is a major reason why tanks fail. While there may be temporary fixes to a corroding tank, it is always best to replace it at once.

Operation of Electric Water Heaters

The electric unit is wired to a volt circuit. For the water to get heated, the current passes through the electrical resistance heating elements. When the temperature drops, the switch closes. But, when the temperature reaches its preset limit, the switch opens.

When a hot water tap opens, there is a dip tube that allows cold water to enter the tank. Gradually, as the water at the top of the tank is replaced by cool water, the temperature at the thermostat drops and its elements kick in.

Fuel-fired water heaters

Unlike electric heaters with electrical resistance elements, gas fired heaters come with burners that are supplied with gas through a valve. As a result of the fact that fuel-fired heaters heat the tank which in turn heats the water, there is more wear and tear than electric heaters.

What is a pilot light?

Having your water heater performs the function it is expected to is a great feeling. It makes you enjoy the value of your money. When you get to the bathroom, and you put on the hot water, you expect the water that would come out to be hot. Sometimes you may be disappointed as a result of a pilot light that keeps going out.

The source of power for your gas water heater is a small gas flame referred to as a pilot light. When this light goes off, your water heater stops functioning well. This is why the pilot light is deemed as an essential component of your entire water heater system. To put it very simply, the way your car would go out when the gas finishes, is the same way your water heater runs out when the pilot light goes out.

When your pilot light stops working, there is a resultant effect on your heater thermocouple. The thermocouple is the device that serves the purpose of detecting whether your pilot light is on or not. Therefore, if your thermocouple cools down, it generally assumes that your water heater pilot light is off. Consequently, your water heater will not ignite.

Factors that could be causing the pilot light to go out

1. Thermocouple

Essentially, the thermocouple is the tube connecting to either the right or the left of the pilot light. The purpose of this device is to detect whether or not the pilot light is lit or not. If it is not lit, then the water heater turns off.

If the thermocouple is malfunctioning, the pilot light may very well go off. Sometimes the thermocouple may be bent, causing the pilot light to go off. In this case, it can be carefully bent back to position. However, care should be taken to avoid breaking the tube.

2. Dirt

Another possible factor that may be causing the pilot light to go off consistently is dirt. If it is clogged with dirt, it can easily be tampered with. If not quickly addressed, this dirt can grow into a hindrance that gets in the way of sensors such as the thermocouple.

3. The inadequacy of gas supply 

The gas supply is the source of power for your water heater. Without it, your water heater cannot work adequately. Without adequate gas flow, your pilot light will not even show signs of starting up. Without gas, you have no means of getting your water hot unless you are using an electric water heater.

Your pilot light will go off arbitrarily or even permanently if you do not have a proper flow of gas. Check your gas supply to ensure that gas is adequately supplied. If you notice something abnormal, call your service providers.

Fixing your pilot light

If you have the requisite technical skills, you can easily troubleshoot your water. If you, however, do not like to go mechanical with your appliance, you may want to call your HVAC professional. Doing so will prevent the problem from getting more complicated.

If you want to take care of a faulty pilot light, here are a few pointers for you:

1. The pilot light can be re-lit

The pilot light is not hard to locate and can be easily re-lit. When your pilot light goes off, the first thing you should do is to try to light it. As a result of the variance in the openings and depth in water heaters, it is preferable that you use a long lighter in trying to relight the pilot light.

First of all, ensure the gas supply is turned on for the heater. After this, turn the water heater off and remove the cover to locate the pilot. Once this is done, lighting the pilot is as simple as holding down a button and lighting the gas using a lighter.

Once you light the pilot, make sure you continue to hold down the pilot button for some minutes so that the pilot light will stay lit. Once you release it, turn the knob back on, and test what you have just done by keeping it on “Test.”

If the pilot light goes off again, then something must be wrong beyond relighting the pilot. At worst, you may have to call a professional for your water heater repair.

2. Fixing a thermocouple

The thermocouple is another component that may need adjustment. Once the thermocouple fails to detect whether or not the pilot light is lit, then it is defective. A new thermocouple will adequately detect this and cause your water heater to function well. The following steps should come in handy when replacing your thermocouple.

To replace the thermocouple, be sure to turn off the shut-off valve located in the gas line. This should be done in a way that the handle would be at right angles to the pipe. After this step, unscrew the three nuts at the control valve and then pull out the entire burner assembly.

Unscrew the thermocouple or pull it out as a whole depending on the type of heater and the type of fittings. Then, take the thermocouple to a spare parts store where you can buy the exact model. Fix in the new one the way you brought out the old one and then light the pilot light.

Also, it is vital that you test for gas leaks. For this test to be done, you must have the burner on, and the pilot lit so that gas will be flowing. That way, you can test whether there is a leak or not. This test is a dangerous prospect and is best handled by an HVAC expert.

  • Caution: It is essential to know that you should not be smelling gas throughout the process of troubleshooting your heater. A slight whiff during the process is normal. However, if you can detect the heavy scent of gas, you have to leave the house immediately and call your HVAC professional.
  • Also, you should not try to tamper with certain thermocouples. If you notice that the thermocouple is a closed one which is always difficult to access, it is best to leave it to the professionals.

3. Where dirt is the problem

If a buildup of dirt is the problem, you can easily facilitate a clean-up. Generally, you should see the dirt stacked up if dirt is the problem.  A common and easy solution is to clean up the pilot light and the thermocouple. If it does not look like dirt is the problem, then you may have to call in the experts.

A pilot light is important to the workings of your gas heater. If it is faulty, you don’t have to wait around for it to get fixed. Call in the professionals right away. Our HVAC experts are adequately trained to help you with any pilot light issues. Call us today!