Allied Air 14A50 2-stage Pressure Switch

Product Description

The ALLIED AIR 14A50 is a 2-stage pressure switch designed for use in gas furnace applications where draft inducer proving is required at two discrete pressure setpoints. The high-stage setpoint is 0.50 inches water column (WC) and the low-stage setpoint is 0.35 inches WC. This switch monitors negative pressure in the flue or inducer circuit and signals the furnace control board when safe combustion airflow conditions are confirmed at each firing stage. Installation is typically performed by a licensed HVAC technician as part of a furnace diagnostic, repair, or commissioning procedure.

This pressure switch is suited for residential and light-commercial gas furnaces that operate on a two-stage heating sequence. In a two-stage furnace, the inducer motor ramps up to generate sufficient negative pressure before each burner stage is allowed to light. The 14A50 provides the dual-setpoint sensing needed to verify inducer performance at both low-fire and high-fire stages. Also referenced by Lennox cross-reference part number 104549-08.

Key Features

• Two-stage pressure sensing with distinct high-stage (0.50 inches WC) and low-stage (0.35 inches WC) setpoints
• OEM-style replacement for gas furnace flue and inducer proving circuits
• Compatible with two-stage furnace control sequences requiring separate pressure confirmation at each stage
• Cross-references Lennox part number 104549-08

Compatibility

This part is also referenced under Lennox part number 104549-08. Designed as an OEM-style replacement for two-stage residential gas furnace pressure switch applications. Confirm setpoints and hose port configuration against the existing switch before installation.

Installation Notes

A licensed HVAC technician should perform this replacement. Shut off power to the furnace at the disconnect or breaker before removing the existing switch. The pressure switch connects via rubber hose to the inducer housing or collector box and wires into the low-voltage control circuit; verify hose integrity and port sizing during replacement. Do not restore power until all wiring connections and hose fittings are secure. Consult the furnace wiring diagram and applicable mechanical codes before beginning work.

Technical Specifications

• Switch Type: 2-Stage Pressure Switch
• Set Point High: 0.50 inches WC
• Set Point Low: 0.35 inches WC

Standard Information

• Brand: ALLIED AIR
• Manufacturer Part Number: 14A50