Troubleshooting pilot light problems on gas water heaters. How to fix the water heater when the light goes out, does not light, won't stay lit, the pilot flame is too small or too large. How does it work and how to recognize is it operating correctly or not?
A pilot light is a small device that is designed to provide the flame and light the gas coming out of the gas valve and main burner. It is common on fireplaces and older/cheaper furnaces and water heaters.
A pilot light is always burning while using a small amount of gas, either a water heater is running or not. Once there is a need for heating (or call from a thermostat), a gas control valve releases the gas into the main burner, and the pilot light ignites the gas.
Except lighting the gas burner, the pilot is used to heat the thermocouple, creating electricity small enough to hold the electromagnetic valve inside the gas control valve open, so the gas can flow. If there is no pilot light or is blown out, the tip of the thermocouple cools off and stops generating electricity so the gas valve closes and the unit shuts off. Every gas appliance is equipped with similar safety devices, prevent gas leaking inside the house.
The pilot is widely used due to its proven and reliable work, but its main disadvantage is wasting gas when not working.
To prevent problems with the water heater pilot light, it is crucial to read the manufacturer's instructions carefully, especially how to maintain the gas water heaters and how to light the pilot. Otherwise, if the pilot light is not functioning correctly, the unit won’t turn ON, and you won't have hot water. Note that most of the older and economy gas water heaters are equipped with the pilot, while newer, advanced models utilize piezoelectric sparks or a hot surface igniter which is more durable and reliable.
Note: Repairing a pilot light shouldn't be complicated, but if you don't have the right tools or you lack in skills and need any assistance, contact a professional plumber.
Did you know that by looking at the pilot flame you can say is it working as it should, or not?
Most of today's energy efficient water heaters will produce a certain amount of condensate.
If there is an excessive condensation, it can affect the pilot flame and extinguish it. The condensate, in this extreme case, is running down the flue tube and is dripping on the burner assembly, which results in the pilot outage. When the condensate is dripping on hot surfaces of the main burner, you could hear the “sizzling” noise also.
There are several reasons why condensation happens, and some include high efficient water heaters which produce flue gases with the lower temperature, undersized heater, when the incoming water is very cold and when you start the unit for the first time. Check out this article to learn more about condensation and its effect on the water heater.
Most of the time improper venting would cause the pilot outage on direct vent gas water heaters (DV). Down-draft from the ceiling fan, draft at the bottom of the unit, or high winds are also common reasons when the pilot would go out.
If there is a restriction in the fresh air delivery, find the reason and remove the obstructions. The right amount of air should be delivered when the unit is installed in the small confined space. If the wind is blowing directly into the DV vent, it may cause the pressure imbalance. If the water heater is installed in an attic, an excessive heat (above 250 F) could be another reason.
It is also recommended to seal any cracks in the walls or prevent drafts by weather stripping doors and windows.
One of the reasons why there is no hot water is when the burner did not ignite, and this is happening when the pilot light does not light. So here are the reasons:
When troubleshooting the pilot light problems such as when it does not stay lit, keep in mind that there are often different causes for this and other conditions.
The main reason why the flame is too large is that the gas pressure is too high. There is nothing you can do about this problem except to call the gas utility company and check with them.
Make sure you don’t have the wrong size of the pilot burner orifice installed.
Also, some homeowners reported that while they were cleaning the unit, a small orifice cap found on top of the pilot tube fell out making the pilot light unstable, yellow and very high.
If the gas pressure is too low, the flame can become too small. Check with the utility company about this problem. Also, a pilot light tube and its orifice might be clogged with the dirt coming through the gas line. Some elements you can clean, but if there is dirt in the incoming gas line, you should notify your utility distributor and check with the gas technician about installing the dirt trap in the gas line.
If you have the wrong pilot burner replace it with the correct one.
Important: Before troubleshooting the pilot light, keep in mind that a pilot flame is always ON and the flame should be blue. If it is yellow, it needs an adjustment. Make sure that the tank is completely filled with water before lighting the pilot light.
Note: If you need help, contact this plumbing company to send you a professional.
Please describe the problem in details including the type of water heater and brand/model.
Click below to see contributions from other visitors to this page...
Pilot light goes out after the water heater has been running for a few minutes.
I have a Master Plumber Reliance 501 Gas hot water heater. It is give or take 15 years old and have never had a problem with it. Came home yesterday and …
Pilot light won't stay lit when you turn knob from pilot to on, it goes out as soon as the knob pops up before you can turn it to on
pilot light on my Reliance 501 gas water heater won't stay lit when you turn it from light pilot to on, it goes out as soon as the knob pops up. What …
LP gas water heater pilot would not light. Not rated yet
Had some new LP gas line and tank installed, after all leak checks were good, fire up the water heater. Got hot water and the next morning still working …