Electronic Ignition Systems and Standing Pilot

Modern gas furnaces use electronic ignition systems to light the burners in modern furnaces. One can still purchase a gas furnace or water heater with the old standing pilot ignition systems which have been proven reliable and safe over time but why would someone want to purchase a gas furnace or water with a standing pilot ignition system rather than purchase a gas furnace or water heater with an electronic ignition system? Let's define the two different types of gas furnace or water heater ignition systems and then we will surmise based on that why someone would purchase a standing pilot gas ignition system over an electronic ignition system.

Standing Pilot Gas Valve

Standing pilot ignition systems use a pilot light that is lit 24/7 to ignite the main burners. A standing pilot ignition system has a pilot light assembly and a thermocouple or thermopile (the two, thermocouple and thermopile are different but produce the same result) that is always in the flame. The flame keeps the thermocouple or thermopile hot. When heat is applied to a thermocouple or thermopile they produce a very small amount of electrical current which keeps a solenoid in the gas valve open. If the fire ever goes out on the thermocouple it stops producing this small amount of current and the valve in the gas valve closes preventing any gas from being delivered to the main burners.

Most often if there is a problem with the standing pilot gas ignition system it is with the thermocouple or thermopile itself and it needs to be replaced. However, there are situations where the pilot gas line gets fowled or clogged with debris or trash and will not permit the proper amount if gas to the pilot tip. A thorough cleaning of the pilot assembly is in order in this situation. There are also those rare occasions when the gas valve goes bad and needs to be replaced. This can happen especially when the gas valve for the standing pilot gas ignition system gets submerged under water or is located in moist spaces where it is possible for corrosive affects from moisture to occur on the gas valve. Gas valves are durable but if submerged under water or to excessive moisture conditions they will corrode as will most metals or any type of gas valve will in conditions of that nature.

The standing pilot gas valve, the thermocouple, and the thermopile are all components that are time tested as reliable and effective to safely light the main burners of a gas furnace, boilers, or water heaters. While the standing pilot gas ignition systems are prone to problems with the proper maintenance the standing pilot gas ignition systems are reliable for many years especially if proper and routine maintenance is performed on these systems. The downside to the standing pilot gas ignition system is they require a pilot light to be lit all the time to function and this means the standing pilot gas ignition system needs to use gas all the time. Another downside to the standing pilot gas ignition system is it adds heat to the system even in the summer. The will cause your air conditioner to work a little harder to remove the heat added by the continuously burning flame of the standing pilot light.

In conclusion for the standing pilot gas ignition system, the standing pilot gas ignition system is reliable and time tested with few problems especially with proper maintenance but the standing pilot ignition system is not as efficient as an electronic gas ignition system because it uses gas even during off cycles of the main burner and the standing pilot ignition system adds heat to the system even in the summer. This causes the overall system to suffer slightly when it comes to efficiency.

Electronic Ignition Gas Ignition Systems

Electronic Ignition has also been proven safe and reliable for igniting the main burners for a gas furnace, water heater, or boiler system which uses gas. Electronic ignition only utilizes energy when the furnace, boiler, or water heater calls for heat. Most modern electronic ignition systems use direct ignition to the main burner however there are indirect electronic ignition systems that will automatically light a pilot and once that pilot flame has been proven the electronic ignition system sends a signal to turn the gas on to the main burners so the pilot light can light the main burners.

An electronic gas ignition system utilizes solid state controls for igniting the flame and proving the flame is lit. Electronic ignition gas systems do not use a thermocouple or thermopile to prove the flame as with a standing pilot gas ignition system. Electronic ignition gas ignition systems use a flame sensor that measures microamps to prove the flame. When the flame sensor becomes fowled it can prevent the proper amount of microamps from being read by the electronic ignition solid state control. In this case the flame sensor needs to be cleaned. The electronic ignition gas ignition system has been proven to be reliable and safe and is currently being used in many furnaces, boilers, and water heaters all over the world for gas ignition.

Electronic ignition gas ignition systems are more efficient than standing pilot gas ignition systems because the electronic ignition gas ignition systems utilize energy only when needed and with gas furnaces, gas fired boilers, and gas fired water heaters that utilize electronic ignition this is only on a call for heat or a call for the gas furnace, gas fired boiler, or gas fired water heater to fire. This makes electronic ignition gas ignition systems more efficient than standing pilot systems.

After this the conclusion is that the electronic ignition gas ignition systems are more efficient and just as reliable as the standing pilot gas ignition system so why would anyone want to specify a gas furnace, gas fired boiler, or water heater with standing pilot ignition when they can have a more efficient system with electronic ignition? We can only surmise but here are the possibilities:

• Cost - a standing pilot gas ignition system is cheaper versus the electronic ignition system
• Technical - the standing pilot gas ignition systems are easier to troubleshoot.
• Some people don't want to try new technology when they have grown comfortable with the older and reliable standing pilot gas ignition systems

These are the possibilities for people who would rather have a standing pilot gas ignition system versus the electronic ignition gas systems. If you have other valid reasons why people select a less efficient but reliable standing pilot gas ignition system over the electronic ignition system please email us.

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Why Choose a Pilot vs. Electronic Ignition?
written by Don Winston, October 31, 2009

For water heaters, which typically don't have an electrical connection (unlike a furnace or boiler, which do), an electronic ignition system will require an electrical hookup.

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written by Alli Berry, December 08, 2009

The main reason I'm looking into this issue is that we currently have an electric ignition furnace which is a problem when the power is out. We're also looking into generators or a secondary heat source, but it seems that this must be a common issue. How do you address it?

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