The purpose of the pilot light is simple—to ignite the gas coming out of the main burner. When the pilot light fails to work properly, one of several factors may be affecting it.
Many gas fireplaces have a standing pilot light, a small gas flame that runs continuously. When the gas is turned on, the pilot light ignites the main burner in the fireplace. A common callback for fireplaces, however, is for a failing pilot light. Pilot lights are rarely blown out by the wind; rather, air currents can blow the light off of the flame sensor, preventing the sensor from picking up the pilot light. In addition, if the flame sensor is adjusted incorrectly, it may tell the valve there isn't a flame, even if there is one. In both scenarios, the pilot light is working, but there are factors preventing it from igniting the main burner.
Cause 1:
Installing the flue without an elbow
An elbow is a length of pipe that creates a 45° or 90° bend in the flue. Without an elbow, the flue makes a direct path for air to flow to the pilot light. Air moving through the flue can move the pilot light off of the flame sensor, preventing the fireplace from lighting.
ProTip!Typically, it's more economical to exit the flue horizontally through a side wall, instead of vertically through the roof, because the length of the flue is shorter.
Solution
Install an elbow pipe as part of the flue in order to decrease the chances of the pilot light failing. An elbow adds resistance to the flue and prevents air from traveling down a direct path to the pilot light. When installing the flue, attach it to the top of the fireplace, rather than to the back. Attaching it to the top will help keep air from moving the pilot light. Consider choosing a fireplace with an ignition system, instead of a standing pilot light. An ignition system, such as an electronic or direct spark system, doesn't use a standing pilot light. An ignition system also helps homeowners save energy and money, since the pilot light isn't constantly running.
Cause 2:
Improperly adjusting the draft shield
The draft shield is part of the horizontal termination cap. It plays many roles in helping a fireplace function properly. The draft shield provides a barrier to water intrusion. It also helps control the direction of hot flue gases and access to combustion air. More importantly, the draft shield helps block drafts from traveling down the flue to the firebox. However, when the draft shield isn't adjusted according to the manufacturer's specifications, wind blowing across the termination cap can create different air pressures between the exhaust and intake portions of the flue. These different air pressures can potentially blow the pilot light off of the flame sensor, preventing the fireplace from lighting.
Solution
Properly install the draft shield by following the manufacturer's installation instructions and clearances. Consider choosing a fireplace with an ignition system, instead of a standing pilot light. An ignition system, such as an electronic or direct spark system, doesn't use a standing pilot light. An ignition system also helps homeowners save energy and money, since the pilot light isn't constantly running.
Cause 3:
Improperly adjusting the flame sensor
A standing pilot light creates a potential safety problem; if the pilot light ever failed, gas would continue to come out of the pilot light tube. To prevent this problem from occurring, the pilot light has a flame sensor that shuts off the gas if it doesn't remain heated. The flame sensor acts as a safety device, preventing the gas from running without the pilot light. However, if the flame sensor isn't adjusted correctly, it may not be able to sense the pilot light. If the flame sensor isn't installed correctly, it may tell the valve there isn't a flame, even when there is one.
Solution
Properly adjust the flame sensor according to the manufacturer's instructions. Make sure the flame is in contact with the flame sensor. Consider choosing a fireplace with an ignition system, instead of a standing pilot light. An ignition system, such as an electronic or direct spark system, doesn't use a standing pilot light. An ignition system also helps homeowners save energy and money, since the pilot light isn't constantly running.
