Supco NPC112H Negative Pressure Trap

Description

The Supco NPC112H Negative Pressure Trap is an engineered condensate management solution designed for HVAC systems operating under negative pressure conditions. In systems where the drain line is subject to negative pressure — such as those with induced-draft or high-efficiency air handlers — a standard P-trap can lose its water seal, allowing unconditioned air, odors, and contaminants to be drawn back into the equipment. The NPC112H addresses this challenge by maintaining a reliable seal even under negative-pressure differentials, protecting system performance and indoor air quality.

Key Features

• Engineered specifically for negative-pressure condensate drain applications
• Prevents air infiltration and condensate backup in HVAC drain systems
• Maintains a reliable water seal under negative-pressure conditions
• Compact design for easy installation in tight equipment spaces
• Durable construction built to withstand continuous HVAC operating environments
• Compatible with a wide range of air handlers, furnaces, and fan coil units

Applications

• High-efficiency furnaces and air handlers with induced-draft blowers
• Fan coil units and variable air volume (VAV) systems
• Any HVAC system where the drain pan operates under negative pressure

Why Use a Negative Pressure Trap?

Conventional P-traps rely on gravity and a standing water column to block air. In negative-pressure drain configurations, the suction created by the blower can evacuate the water seal, defeating the trap entirely. The Supco NPC112H is purpose-built to overcome this limitation, ensuring proper condensate drainage while blocking reverse airflow — helping to maintain equipment efficiency, prevent mold growth in drain pans, and extend system service life.

Brand

Supco is a trusted name in HVAC/R replacement components, offering a broad range of quality parts for residential and commercial applications.