Allied Air 14A49 Two Stage Pressure Switch 0.85 0.45 Wc

Product Description

The ALLIED AIR 14A49 is a two-stage pressure switch designed for use in gas furnace draft inducer systems. It monitors negative pressure within the inducer circuit to verify proper venting conditions before allowing burner ignition. The switch operates at two set points: a high-stage set point of 0.85 inches water column and a low-stage set point of 0.45 inches water column. This dual-set-point design supports staged combustion control, ensuring the furnace control board receives confirmation that the inducer is operating at the correct pressure for each firing stage. Licensed HVAC technicians install and replace this component during routine furnace service or when diagnosing inducer-related lockout faults.

This pressure switch is suited for residential and light-commercial gas furnaces equipped with two-stage inducer draft systems. It is also referenced as Lennox 104549-07, making it a direct cross-reference for service calls where the OEM part number appears on the existing switch or in service documentation. Typical installation scenarios include warranty replacements and field service on units displaying pressure switch fault codes.

Key Features

• Two-stage operation with independent set points at 0.85 inches WC (high stage) and 0.45 inches WC (low stage)
• Cross-references Lennox 104549-07 for streamlined field identification
• Monitors inducer draft pressure to safeguard burner ignition sequencing
• Designed for integration with standard furnace control board low-voltage sensing circuits

Compatibility

This switch cross-references Lennox part number 104549-07. Designed as an OEM-style replacement for two-stage gas furnace draft inducer pressure switch applications where those set points are specified.

Installation Notes

A licensed HVAC technician should perform pressure switch replacement. Shut off power to the furnace and close the gas supply before beginning work. Inspect the rubber hose connecting the switch to the inducer housing for cracks or blockages, as a failed hose is a common cause of pressure switch faults. Verify the replacement set points match the original switch label before completing the installation.

Technical Specifications

• Switch Type: Two-Stage Pressure Switch
• Set Point High: 0.85 inches water column
• Set Point Low: 0.45 inches water column

Standard Information

• Brand: ALLIED AIR
• Manufacturer Part Number: 14A49