Carrier HH18HA150 L150-40F Furnace High-Limit Switch

Description

Carrier HH18HA150 L150-40F Furnace High-Limit Switch Overview

The Carrier HH18HA150 is an OEM high-limit safety switch designed to protect furnaces and heating systems from dangerous overheating conditions. Designated as the L150-40F model, this limit switch is engineered to open the control circuit when supply air or heat exchanger temperatures reach the upper threshold, shutting down the burner to prevent equipment damage and potential hazards.

How It Works

The L150-40F designation defines the switch’s operating parameters: it opens (trips) at 150°F and features a 40°F differential, meaning it automatically resets once temperatures drop back to approximately 110°F. This automatic reset functionality ensures the furnace can resume normal operation once safe temperature levels are restored, without requiring manual intervention.

Key Features

• OEM Carrier replacement part — engineered for precise fit and reliable performance
• Opens at 150°F to protect against overheating
• 40°F differential — automatic reset at approximately 110°F
• Designed for use in Carrier furnaces and compatible heating equipment
• Helps prevent heat exchanger damage, component failure, and fire hazards
• Direct OEM replacement for straightforward installation

Application

The HH18HA150 is a direct OEM replacement limit switch for select Carrier furnaces. It is a critical safety component that monitors supply air temperature and interrupts the gas valve or burner circuit if temperatures exceed the rated setpoint. Always verify compatibility with your specific Carrier furnace model before installation.

Specifications

• SKU: HH18HA150
• Model: L150-40F
• Brand: Carrier
• Trip Temperature: 150°F
• Differential: 40°F
• Reset Temperature: ~110°F
• Reset Type: Automatic
• Application: Furnace high-limit protection