Suburban Aire SA40 - Front w/ Cover Off

1. Model number
2. Burner Access Door
3. Terminal Bushing
4. Glo-Bar
5. Flame Sensing Probe
6. Flue Limit Switch
7. Heat Exchangers

The Flue Limit Switch(6) shuts off the gas to the main burner if the furvace exhaust or intake becomes restricted.

The Flame Sensing Probe(5) will only allow the unit to operate if the Glow-bar(4) successfully ignites the burner gas. Otherwise the electronic gas valve will close.