Allied Air 27k79 Furnace Limit Switch

Product Description

The ALLIED AIR 27k79 is a furnace high limit switch designed to protect heating systems from overtemperature conditions. When supply air or heat exchanger temperatures exceed a set threshold, the limit switch interrupts the burner circuit to prevent equipment damage and unsafe operating conditions. Licensed HVAC technicians install this control as part of routine furnace service or component replacement. It is a direct-fit part intended to restore safe, code-compliant furnace operation.

This limit switch is suited for residential gas furnace applications where the original high limit control has failed or is reading outside calibration. The raw title references Lennox and Armstrong Air branding, indicating cross-brand applicability within Allied Air Enterprises-affiliated equipment lines. Consult the furnace wiring diagram and OEM documentation to confirm correct temperature rating and mounting configuration before installation.

Key Features

• Interrupts burner circuit on overtemperature to protect heat exchanger and related components
• OEM-style replacement designed for Allied Air, Armstrong Air, and related furnace platforms
• Restores safe high limit protection without system modification
• Compact form factor suitable for residential gas furnace installations

Compatibility

Designed as an OEM-style replacement high limit switch for residential gas furnaces within the Allied Air Enterprises family, which includes Armstrong Air and Lennox-affiliated product lines. Verify temperature rating and terminal configuration against the original part before installation.

Installation Notes

Installation should be performed by a licensed HVAC technician. Disconnect power to the furnace at the disconnect switch or breaker and confirm the gas supply is off before removing the existing limit switch. Follow the furnace manufacturer wiring diagram for correct terminal connections. Installation must comply with applicable local mechanical codes and IFGC requirements.

Technical Specifications

• Component Type: High Limit Switch
• Application: Residential Gas Furnace

Standard Information

• Brand: ALLIED AIR
• Manufacturer Part Number: 27k79