Hot Surface Furnace Igniter Education

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HOT SURFACE IGNITER EDUCATION

All newer furnaces in about the past 10 years, have replaced the old continually burning pilots with these units also called simply H.S.I. On a call for heat from your thermostat the ignitor glows red and then lights the burners in the gas furnace. Because they are continually getting red hot and then cooling, they have a 3-5 year life expectancy. Most people should have a spare on hand for those middle of the night breakdowns. ( A 1/4" long nut driver REALLY helps! ) Also worth mentioning is, most service companies don't carry EVERY one of these on their trucks! You most likely will be able to change them yourself - but remember they are made of a VERY brittle material and will break VERY easily. During installation, EXTREME care should be taken not to bump the carbide section against metal! For these reasons we do NOT except returns! Beware also, different manufacturer's have different quality, while you may find a cheaper price you will probably not get the expected service life as with good quality units!

We carry a full line of the most commonly used hot surface ignitors.

Please use the diagrams and cross reference chart below to determine which one you need. The O.E.M number is the furnace factory part number, the Uni Line number is what you will use for ordering purposes. Compare the style of ceramic block as well as the electrical terminal on the end. Units shown with terminals are usually exact fit replacements, others have no terminal and you must use your own small wire nuts to use your existing terminal and install it on the new ignitor. Your old ignitor terminal can be cut off and installed on the new one if you can't find the correct configuration below. Just be sure to install wire nuts so no loose wires are protruding. Some of these ignitors will have (2) wire nuts included for this purpose.
Once you know which one you need, click on the appropriate link at the bottom of the page and you will be directed to a secure online ordering site where you can purchase them. Also note these units are 120 volt units, there are SOME furnace manufacturers that are using 24 volt ignitors! These 24 volt units will be burnt out instantly if 120 volts are applied to them! Please read the diagrams below carefully before ordering. To view pictures of a typical 24 volt ignitor see the bottom of this page.

Visually look at the ignitor and see if it is cracked or has a white spot on the carbide section. If it is cracked or has a white spot it is probably bad. They last about 3 years. The new unit on the left is black but notice closely that the right unit which failed has a white spot on the left side. It actually has a small crack in it also, which is barely visible in the photo.