Furnace Fault Codes

Furnace igniter fault codes by manufacturer

Igniter codes and grounding codes overlap on several brands, because the control cannot always tell a failed igniter from a bad ground. The codes below show which brands conflate them.

What the hot surface igniter does

A hot surface igniter is a silicon carbide or silicon nitride element that the control energises for a set warm-up period before opening the gas valve. It glows bright orange at temperature. Silicon carbide igniters are brittle and fail open, often from thermal cycling or from being touched during handling — skin oils create a hot spot.

Why one part produces several different codes

Where a manufacturer reports an igniter circuit fault, the control is reporting that it did not measure the current it expected through the igniter. That is an open igniter most of the time, but a poor chassis ground or reversed line voltage polarity produces the same reading on several brands, which is why Goodman, Trane and York all pair the two causes in a single code.

Every hot surface igniter code on this site

7 codes across 6 control families. The meaning is the manufacturer's, from the document listed at the foot of each code page.

BrandCodeWhat it reports
Goodman8 flashesIgniter circuit fault, most often caused by poor grounding
Goodmanrapid flashingReversed 115 volt polarity, a grounding problem, or an open igniter circuit
GoodmanE7Igniter fault or improper grounding
Goodman12 red flashesIgnitor relay failure
LennoxAlert code 207Hot surface igniter sensed open
Trane9 flashesIgnitor circuit problem, or low voltage between neutral and 24 volt common
York12 red flashesOpen hot surface igniter

Before you work on it

Checking line voltage polarity and ground means working inside a live furnace cabinet. If that is not familiar work, it is a technician call.

Other parts

Sources

Every code meaning above comes from the manufacturer document behind its code page:

This site is a reference, not a substitute for a licensed HVAC technician. Gas appliances can leak carbon monoxide and cause fire. Anything involving gas lines, the heat exchanger, or the flame sensing circuit should be handled by a licensed professional. Pages are written with AI assistance from the sources listed on each page and checked against them before publishing.