High limit and rollout switches

What furnace high limit and flame rollout switches protect, which codes mention them and why we do not link replacements.

Updated

What it is

The high limit switch opens if the furnace overheats. The flame rollout switch opens if flame rolls out of the burner compartment. Both are safety devices. Lennox, Trane and Carrier list dirty filters, blower faults, restricted flue piping and burner misalignment among the causes.

Trane says never to leave limit switches jumpered.

How to choose

  • We do not link replacement limit or rollout switches. Replacing a safety switch without finding why it opened is exactly the situation the manuals warn about.

How it is tested

  • Start with the cheap, safe cause: a dirty filter (see the air filter guide).
  • Everything beyond that (static pressure, heat rise, flue, burners, gas pressure) is a technician check.

Replacing it

  • Technician only.
Safety firstGas, venting, high-voltage and control-board work belongs to a licensed HVAC technician. This page is here so you can recognise the part and read a quote, not as a how-to for working on a gas appliance.

Capacitors can hold a charge after the power is off. Safety terms.

Where to buy

We do not link replacement safety switches. Replacing one without finding out why it opened is the situation the manuals warn about, so this page explains the part and leaves it to a technician.

Codes that mention it

Error codes whose own causes or steps name this part or check.

Amana

Amana EE3Amana EEd

American Standard

American Standard E04American Standard E09American Standard E2.2American Standard E3.2

Bryant

Bryant 13Bryant 33

Carrier

Carrier 12Carrier 13Carrier 33

Goodman

Goodman E11Goodman EE3

Lennox

Lennox E200Lennox E250Lennox Red on, green slow flashLennox Red slow flash, green on

Rheem

Rheem 33Rheem 61

Trane

Trane E04Trane E09Trane E2.4

Per-brand lists: Amana furnace · American Standard furnace · Bryant furnace · Carrier furnace · Goodman furnace · Lennox furnace · Rheem furnace · Trane furnace · York furnace.

Sources