Standing Pilot vs. Intermittent Pilot Ignition

All safety tested gas appliances use a series of switches, sensors, valves etc. to both ignite the fire as well as provide a safety system in case a part fails. There are two common types of ignition systems used in the fireplace and outdoor industries. Standing Pilot Millivolt Ignition systems and Intermittent Pilot Ignition Systems.  There are variations of both of these systems from different manufacturers but the information below will lay out how each works and keeps you safe. One of the original types of ignition systems to be used on gas fireplaces, stoves, inserts, and fire pits is the millivolt ignition system. This system requires that a pilot light be lit either with a push button igniter or with a lighter or match. The pilot light heats up one or two sensors. When these sensors are heated, they create a small electrical charge. This electrical charge is sent through a wire or wires back to the valve to energize a magnet. This magnet opens up the pathway for the gas to continue to flow through the valve system. When a switch is turned on, it will open up the gas to the burner. If you remove the pilot light, you remove the heat which removes the electricity, this de-energizes the magnet and shuts the unit off. This prevents the flow of unwanted gas in the case that either the pilot light or burner flame is extinguished. Because of the electrical circuit that is created an on and off switch or a remote control can be used to operate the appliance once the pilot light is lit. Millivolt Quick Notes:
  • The system has been in circulation with fireplaces, furnace, hot water heaters, for 50+ years. Most installers and technicians are familiar with it. Should anything fail, it is very easy to diagnose.
  • All appliances using a millivolt gas ignition system can use an on/off switch or a remote control. This allows you to use the appliance with a flip of a switch or from your recliner.
  • The safety it provides, gives you piece of mind knowing that in the rare occurrence there is a failure that the unit will mechanically shut down.

Millivolt Gas Valve Image Courtesy Of Kingsman Fireplaces

The terms Intermittent Pilot, Pilotless, Intellifire, IPI, IP, and Electronic Ignition are typically all referring to an electronically ignited burner system. This system requires electricity to operate whether in the form of 120VAC power or batteries. Intermittent Pilot Ignition Systems feature a control module/board to carry out the ignition system. Once the switch or remote is used, the ignition sequence begins. First, the sparker will begin to spark and electricity is sent to the pilot side of the valve to energize the electromagnetic device to open up the pilot gas. When you have spark, fuel, and oxygen, the pilot will light. As soon as the pilot is lit, the pilot flame engulfs a sensor which sends a signal back to the units control module to shut off the igniter and send electricity to the burner side of the valve to open it up and allow the pilot light to ignite the main burner flame. Intermittent Pilot Quick Notes:
  • Without a standing pilot light you are not using fuel when not using the appliance.
  • Most intermittent pilot systems have a battery back up feature that can operate the system for several months or more. This allows the unit to be used in a power outage.
  • Because the system is a little more complex, an experienced tech will be need on site should the unit not work properly.
  • If the pilot sensor does not sense the pilot light, the system will not work and no unwanted gas will pass through the system

Intermittent Pilot Gas Valve Image courtesy of Kingsman Fireplaces.

January 15, 2019
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