The Trane SWT3968 Rollout Switch is a genuine OEM L190F manual reset flame rollout safety switch designed to protect Trane, American Standard, and compatible gas furnace systems from unsafe burner flame conditions and excessive temperatures.

Rated at 190°F (L190F), the SWT3968 monitors the burner compartment for abnormal heat or flame rollout conditions. If temperatures exceed the switch's safety threshold, the switch opens the control circuit and shuts down furnace operation. Unlike automatic reset limits, the SWT3968 requires manual reset, helping ensure the underlying cause of the fault is diagnosed and corrected before the furnace is returned to service.

This safety device plays a critical role in protecting the heat exchanger, burner assembly, wiring, and surrounding furnace components from damage caused by blocked heat exchangers, venting restrictions, or combustion issues.

 Cross‑Reference 

Replaces 10123537 Goodman manual reset limit switch L190F

L190F Manual reset limit switch 
Size 36TXV16

Direct OEM

• SWT3968 — Trane Rollout Switch

Compatible Brands

• Trane
• American Standard

Specifications

• Temperature Rating: L190F
• Trip Temperature: 190°F
• Reset Type: Manual Reset
• Type: Flame Rollout Safety Switch
• Application: Gas Furnace Safety Circuit
• OEM Replacement: Yes

Application

• Burner Compartment Protection
• Flame Rollout Detection
• Furnace Safety Shutdown
• Gas Furnace Safety Controls

Related Components

• High Limit Switches
• Pressure Switches
• Draft Inducer Assemblies
• Furnace Control Boards
• Burner Assemblies

 Technician Notes

Common Causes of Rollout Switch Trips

• Cracked heat exchanger
• Blocked flue or vent pipe
• Failed inducer motor
• Restricted combustion air
• Burner misalignment
• Delayed ignition
• Blocked heat exchanger passages

Common Symptoms

• Furnace completely inoperative
• Rollout switch open fault
• Manual reset button popped
• Burners shut down shortly after ignition
• Furnace lockout conditions

Installation Tips

• Never bypass a rollout switch.
• Determine and correct the cause before resetting or replacing.
• Inspect heat exchanger for damage.
• Check venting system for restrictions.
• Verify proper combustion and burner flame pattern.
• Test furnace operation after installation.