How many Saftey Switches are there?

[MentaRockks]

I am trying to identify all of the safety switches on a furnace (we have about 25,000 furnaces to deal with so its not just 1 model) that might need to be repaired and in the order of the most common to the least common replacement issues. Below is what I have so far, can someone please correct me or tell me what I am missing?

1 High Limit Switch
2 Fan Control Limit Switch
3 Roll Out Switch
4 Draft Safeguard Switch
5 Door Safety Switch
6 Pressure Switch

Thank you in Advance

[STEVEusaPA]

Just Gas/Propane units?

[BNME8EZ]

Aux limit in the blower compartment.
Pilot safeties
Gas pressure switches (Bryant LP unit)

On the draft safeguard are you considering draft hood and inducer mounted switches?

[MentaRockks]

Just Gas

[doug1111]

Fire/stats - behind air return grill

[joemach]

I would consider the flame sensor a safety.

[MentaRockks]

Aux limit in the blower compartment.
Pilot safeties
Gas pressure switches (Bryant LP unit)

On the draft safeguard are you considering draft hood and inducer mounted switches?

I am not to sure on the draft safeguard switch, I was thinking that was only for the draft hood and the inducer motor mounted switch was the pressure switch or vacum switch. We work mostly with 80% furnaces.

Thanks for the reply

[BNME8EZ]

I am not to sure on the draft safeguard switch, I was thinking that was only for the draft hood and the inducer motor mounted switch was the pressure switch or vacum switch. We work mostly with 80% furnaces.

Thanks for the reply

I know that Trane has a limit switch that mounts to the inducer on their 90% in case the exhaust gets to hot and Carrier has a limit switch on the box on the outlet of the inducer on their older 80%.

The pressure switch on the Bryant was on their LP units and was piped off the inlet pressure port on the gas valve.