Hot Surface Igniter Voltage Test: You disconnect the old hot surface ignitor and place your meter leads on the wires coming from the board. Use a screwdriver to check you oil burner transformer. In order to check the ignitor by testing the circuit and inspecting the furnace for visual damage, the furnace must be set at room temperature. This article will help you understand why the voltage that goes to your furnace ignitor … The transformer steps up your 120 volt house voltage to several thousand volts to produce a spark across the terminals of an igniter. Usually, the technician will remove the service panel of the furnace, inspect for any damage, remove the ignitor wires, and then use a multimeter to test the ignitor. Unscrew and remove the service panel on the side of the furnace and find the ignitor. A higher setting on the thermostat means more gas should be passed to the ignitor. Before you replace the ignitor, try cleaning it with a quick blast of air. The key, again, is to be careful because of how fragile these can be. Cut off the circuit breaker. These newer furnaces do not use a pilot-light system as the older furnaces did. Since it is apparent that the control buttons and gas lines are working, my first guess would be the ignitor has weakened to the point where it is no longer able to send a sign… They may remove the ignitor wires and they will test the ignitor with a tool called a multimeter. Close the oil valve on the line connected to your furnace. Old igniter: Electronic ignition systems aren’t designed to last for the lifetime of your furnace. When the thermostat kicks on to start the furnace, the ignitor creates a spark that "ignites" the gas connected to your heater. Greater than 90 ohms indicates a failing or failed hot surface ignitor. Although you might immediately think you need to call heating experts for your furnace ignitor problems, there are a few ways to troubleshoot the problem yourself. The new part goes back in the same way the old part came out, only more carefully. A good reading is 115 to 120 VAC. How to Perform A Resistance Test One manufacturer (Norton) recommends performing a simple room temperature resistance (RTR) test after installing the igniter. 3. The circuit switch should be marked "furnace." If you don’t see it, you likely have a bad ignitor. Reset the Igniter Switch the igniter to the "off" position and wait at least five minutes before turning it back on. Instead, these ignitors heat up and touch the surface of the gas to heat the air blowing from the furnace. Turn off the circuit breaker for the furnace, often located on the furnace or in the home’s main breaker box. High-Temperature Limit Switch. Check to see that the circuit breaker for the furnace is not tripped and provides power to the unit. Pull the ignitor, and check whether it is getting power or test it directly to check resistance. Switch the igniter to the "off" position and wait at least five minutes before turning it back on. When it comes to figuring out how to tell if your furnace ignitor is bad, the clear first step is to figure out what exactly a furnace ignitor is. Power down the furnace and close the oil valve. Your furnace is built with a limit switch to prevent extremely high temperatures in the unit. First, shut down the furnace if it is operating. The ignitor needs to get super-hot so that it ignites the gas/air mixture needed for combustion. Some furnaces may have a red button that you have to push to reset it. Fixing low voltage on a furnace ignitor starts with a test on the main control boards and looks for loose and damaged wires, checks for opened switches, and identifies the area where voltage is being lost. Also clean any dirty air filters before trying to reset the igniter. Disconnect the hot surface ignitor from the control board and measure the resistance. Most furnaces have two sections, with one area containing the actual burner box and igniter. The examination may require the removal of the service panel to look for any damage or wear. Search around your furnace for an on and off switch. Turn Off The Furnace. However, you may be able to get the furnace working by turning off the igniter and resetting it. Using The Wrong Ignitor: Ignition failure will happen if your furnace uses an ignitor that has the incorrect voltage. The ignitor takes a small amount of electricity and ignites the fuel to create the heat in your furnace.Repairing this item usually means replacement. All Rights Reserved. The burner door covers the burner box and igniter. Remove the burner door from the furnace and temporarily set it aside. A dirty ignitor will prevent your furnace from lighting. Write down the finding. If you have over 110v at the ignitor connector you can know that the ignitor is bad. Find the paperwork for your particular furnace to locate the reset button or switch. Mismatched Ignitor. A good hot surface ignitor will have a resistance of 40 to 90 ohms. Hopefully, your furnace will fire after installing a new ignitor, and you’ll soon be warm again. Types Of Electronic Furnace … Replacing the hot surface ignitor is simple. Turn off the circuit that powers the furnace. I don't mean to dumb it down, but you just take out a screw, remove the part, and undo the clip. Call for the services of a professional heating and cooling technician when the igniter is not working properly.