Carrier HH18HA192 140-190F AUTO Reset Limit Switch

The Carrier HH18HA192 is an OEM automatic-reset high-limit switch engineered to protect Carrier furnaces from dangerous overheating conditions. When supply-air temperatures exceed the upper threshold, the switch opens the control circuit and shuts down the burner — then automatically resets once temperatures return to a safe level, minimizing nuisance service calls while keeping the system protected.

Key Features

• Auto-reset operation — no manual intervention required after the overheat condition clears
• Trip/open temperature: 190°F
• Reset/close temperature: 140°F
• Differential: 50°F between trip and reset points
• Genuine Carrier OEM replacement part for reliable, drop-in fitment
• Protects heat exchanger and downstream components from thermal damage
• Direct replacement for compatible Carrier furnace models

Application

Designed as a direct OEM replacement limit switch for Carrier residential and light-commercial gas furnaces. Installs in the supply-air plenum or heat exchanger section to monitor discharge air temperature and interrupt the burner circuit upon an overheat event.

Specifications

• Part Number: HH18HA192
• Brand: Carrier
• Reset Type: Automatic (AUTO)
• Trip Temperature: 190°F
• Reset Temperature: 140°F
• Function: High-limit overheat protection