Lennox 13H78 Relay 320074-702 maintaining the precise pressure drop

maintaining the precise pressure drop required to transition high-pressure liquid into a low-pressure saturated vapor

Complete HSI Integration: Replaces outdated pilot assemblies with a modern hot surface ignition system for improved reliability

The York S1-331-09150-000 Control Board Kit is a critical OEM replacement part designed for Simplicity 1A 2/4 stage HVAC systems

The HTP-B drain pan is specifically reinforced to handle the higher temperatures generated by furnaces in upflow configurations

it is the primary successor to the obsolete Honeywell VR8204M1901

Lennox 13H78 Relay 320074-702 maintaining the precise pressure dropThe Lennox 13H78 Relay is a heavy duty 24V DPDT relay engineered for precise switching control within Lennox heating and cooling systems. Built to handle dual circuit switching, this double pole double throw relay manages various voltage pathways simultaneously, ensuring consistent communication between the thermostat and high voltage components like blower motors or compressors. Operating at a standard 50 60 Hz frequency, the 13H78 is a critical HVAC