Before replacing, try cleaning the sensor rod with fine steel wool or a dollar bill. That fixes it about half the time. If it still shuts off after 3–5 seconds, replace it.
18G89 – FLAME SENSOR (LENNOX)
$23.17
Lennox 18G89 flame sensor for Lennox and Armstrong furnaces. OEM replacement with straight probe design. Also cross-references RS36453B001.
Mon–Fri 10 am – 7 pm | Sat 10 am – 3 pm | In-Store Pickup Only
Description
If your furnace lights but shuts off after a few seconds, a dirty or failed flame sensor is the most likely cause. The 18G89 is a Lennox OEM flame sensor that fits both Lennox and Armstrong furnace models.
Specs: Straight probe design, ceramic insulator, OEM Lennox part
Replaces: 18G89, RS36453B001
Fits: Lennox and Armstrong gas furnaces
Need help? See our Furnace Not Heating Guide.
In stock at Open To Public HVAC Parts in Dallas. We test parts at the counter before you buy. Call or text (214) 340-9421.
