The Lennox 15P85 is an OEM replacement pressure switch designed for use in Lennox furnaces and air handling equipment. Pressure switches are a critical safety component in induced-draft and condensing furnace systems — they verify that the draft inducer motor is operating correctly before allowing the ignition sequence to proceed, helping to prevent unsafe combustion conditions.
Product Overview
This pressure switch is factory-set to a 0.55″ W.C. (water column) setpoint, matching the original Lennox specification for compatible equipment. It monitors negative pressure created by the draft inducer blower and opens or closes the circuit accordingly to confirm proper airflow before the burner fires.
Key Features
- OEM Lennox replacement pressure switch — part number 15P85
- 0.55″ W.C. setpoint for precise, factory-matched performance
- Monitors draft inducer operation to confirm safe combustion airflow
- Designed for direct drop-in replacement in compatible Lennox furnace models
- Helps prevent furnace lockout caused by failed or worn pressure switches
- Supports reliable ignition sequencing and system safety compliance
Application
This pressure switch is intended for use in Lennox induced-draft and condensing gas furnaces. Always verify compatibility with your specific furnace model number before installation. Refer to the unit’s wiring diagram and service manual for proper replacement procedures.
Why Replace Your Pressure Switch?
A faulty pressure switch is one of the most common causes of furnace no-heat calls. Symptoms include the furnace failing to ignite, short-cycling, or displaying a pressure switch fault code. Replacing with a genuine Lennox OEM part ensures the correct setpoint and reliable operation season after season.
