Limit switch: Fault Codes That Name It

Codes that name it

Amana

Amana furnace EE3: Loose or improperly connected wiring in the high limit circuit Amana and Goodman *CVC96 / *MVC96 two-stage furnace installation instructions (IOG-2015L) (opens in a new tab) ↗
Amana furnace EEd: Loose wiring in the auxiliary limit circuit Amana and Goodman *CVC96 / *MVC96 two-stage furnace installation instructions (IOG-2015L) (opens in a new tab) ↗

American Standard

American Standard furnace E04: Main thermal limit open American Standard S9V2 installer's guide (18-CE01D1-1E-EN) (opens in a new tab) ↗

Bryant

Bryant furnace 13: Limit switch open longer than 3 minutes Bryant 926TB installation, start-up, operating and service instructions (opens in a new tab) ↗
Bryant furnace 33: Limit circuit fault. A limit, draft safeguard, flame rollout, or blocked-vent switch is open, or the furnace is in high-heat only after two successive low-heat limit trips. The blower runs for 4 minutes or until the switch remakes, whichever is longer. Open longer than 3 minutes becomes lockout 13. Bryant 80% variable-speed two-stage furnace troubleshooting guide (Catalog No. TG-GFB80-02) (opens in a new tab) ↗

Carrier

Carrier furnace 13: Limit circuit lockout: a limit or flame rollout switch was open longer than 3 minutes. Control auto-resets after 3 hours (see code 33). Carrier 59SC5 installation, start-up and operating instructions (opens in a new tab) ↗
Carrier furnace 33: Limit circuit fault: a limit or flame rollout switch is open. Becomes lockout 13 if open longer than 3 minutes. Carrier 59SC5 installation, start-up and operating instructions (opens in a new tab) ↗

Goodman

Goodman furnace EE3: Loose or improperly connected wiring in the high limit circuit Goodman GR9S96/GD9S96 installation and operating guide (IOG-2037B) (opens in a new tab) ↗

Lennox

Lennox furnace Red slow flash, green on: Limit switch open (overheating condition) Lennox ML180UH installation and operation manual (opens in a new tab) ↗

Trane

Trane furnace E04: Open limit: main thermal limit, flame rollout switch, or reverse airflow switch. Trane S9V2 Service Facts (S9V2-SF-2A-EN) (opens in a new tab) ↗

York

York furnace 4 red flashes: Loose limit switch wiring York TG9S installation manual (Johnson Controls 1083287-UIM-C-0715) (opens in a new tab) ↗

Technician part

Limit and rollout switches are safety devices. This page names the codes that mention them and leaves replacement to a licensed technician.

Safety first

Unplug the furnace or switch it off at the breaker, and shut off the gas supply where relevant, before you open any panel. Capacitors can hold a charge after power is off. Gas, electrical-panel, refrigerant and carbon-monoxide work belongs to a licensed professional. Follow the manual for your model (safety terms).