How to re-light a water heater pilot light

Posted on by Andrew LeVahn

water heater pilot light

Re-lighting a water heater pilot light:

A water heater pilot light is the little blue flame at the bottom of the heater that lights the burner when your water heater needs to heat water. The heater will not heat water if the pilot goes out and it will have to be re-lit.

In an older heater (prior to 2002) you are able to relight the pilot with a match or lighter. Water heaters have changed in recent years to comply with new laws to prevent fires and explosions. The reason for the new regulations is because residents  that don’t have basements in their homes usually have their heater located in the garage. That creates a problem when a heater with an open flame is located near lawn equipment and cans of gasoline. The area at the bottom of the heater is now completely enclosed and the only way to relight the pilot is with a igniter that is located on the gas valve.

Check the Thermocouple:

There are a few causes of a pilot light going out. The first cause may be a thermocouple failing. Very simply put the thermocouple sends the message to the burner that the pilot is lit. If the thermocouple fails the burner won’t light and the pilot will go out. In an old water heater (prior to 2002) you are able to replace the thermocouple and hopefully be back in business.

Check the Fresh air intake

The next  issue that you need to consider is the fresh air intake. If you have a traditionally vented heater (i.e. a heater that is gravity vented through a chimney in your home) it is possible that a down draft is occurring due to the fresh air intake being plugged. If the Fresh air intake vents at the base of the heater are plugged with debris the heater may pull its fresh air through the chimney vent. This may cause the pilot flame to be extinguished. To solve this issue you need to clean your air intake vents at the base of the heater and relight the pilot.

Clean out debris from the burner area

Because of these new restrictions water heater manufacturers had to come up with new ways of getting fresh air to the flame while not allowing the possibility of having a fire start or having an explosion. This created issues with pilot lights not staying lit. Most manufactures have some kind of venting that is located at the bottom of the heater. This venting can become plugged with debris and not allow combustion air to be taken in to keep a flame lit.

water heater combustion chamber

New Water Heater Combustion Chamber

Adding to the problem is debris that may get sucked in to the heater itself. Water heaters used to have combustion air coming in from all sides. This design allowed for a more than adequate air supply to enter the heater keeping the flame and burner lit. With the new heaters the size of the air ports for fresh combustion air to enter the heater have restricted the air supply. The amount of air needed is the same however the size of the hole that the air has to enter has been choked down causing a vacuum effect. This causes debris to enter into the heater itself and plug  screen that is located in the heater that was added as a safety shield to prevent any flames from escaping the heater. If this occurs it is possible, although difficult, to blow out the debris. Call us and have one of our professional master plumbers take care of this issue.

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If you have more questions contact

LeVahn Brothers Plumbing at 763-551-8990

Come see us at 12700 Bass Lake Road Maple Grove, Minnesota

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About Andrew LeVahn

I am the fourth generation of LeVahn's. I have been working at LeVahn Bros. since 1994. I went to Minnehaha Academy for high school and Bethel University for college. View all posts by Andrew LeVahn → This entry was posted in How to, Plumbing, Plumbing Parts and tagged , , , , , , , , , , , , , . Bookmark the permalink.

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