Lennox 18M65 Gas Valve

The Lennox 18M65 is a high-performance 1/2" 2-stage natural gas valve designed for precision fuel regulation in residential and light-commercial furnaces. As an authentic OEM replacement part, it is functionally identical to the Lennox 18M6501 and serves as a direct substitute for the Honeywell VR8205Q-2746. This 24VAC valve is engineered to handle up to 150,000 BTUH, providing the staged firing rates necessary to maintain high-efficiency standards in models like the G60UH series. The 2-stage gas control logic allows the system to shift between low-fire and high-fire modes, ensuring consistent manifold pressure and reducing temperature swings. Built with standard 1/2" NPT inlet and outlet ports, this Lennox gas furnace valve simplifies field retrofits while maintaining original equipment safety parameters. When troubleshooting Lennox furnace ignition failure or short-cycling, verifying solenoid resistance and 24V signal at the 18M65 gas valve is critical to ensuring reliable combustion cycles and proper heat exchanger performance.

• Dual-Stage Modulation: Supports both high and low heating stages for optimized fuel efficiency and quieter operation.
• Exact OEM Fit: Drop-in replacement for Lennox 18M6501 and Honeywell VR8205Q-2746, eliminating the need for manifold modifications.
• High Capacity Rating: Rated for up to 150,000 BTUH, making it suitable for a wide range of mid-to-high efficiency gas furnaces.
• Standardized Connections: Features 1/2-14 NPT threading for a secure, leak-free integration with existing gas piping.
• Reliable 24V Control: Designed for seamless interface with Lennox integrated furnace control (IFC) boards.

Is the Lennox 18M65 compatible with LP (Liquid Propane) systems?
The 18M65 comes factory-configured for natural gas. For LP applications, a specific conversion kit must be installed by a licensed technician to ensure the correct spring and orifice settings for propane's higher energy density.

What are the symptoms of a failing 18M65 gas valve?
Common indicators include the inducer running and igniter glowing without flame established, or the furnace "clunking" as the solenoid fails to pull in. Technicians should check for 24VAC at the valve terminals during the ignition trial.

Can I use a single-stage valve to replace this 2-stage valve?
No. The furnace control board and wiring are specifically designed for 2-stage logic. Replacing the 18M65 with a single-stage valve will lead to error codes, poor efficiency, and potentially unsafe operating conditions.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.