Waterless Trap Valve 40mm Self Sealing

This 40mm waterless self‑closing trap valve features a 40mm female BSP inlet and 40mm PVC compression outlet, and can be installed horizontally or vertically for flexibility. The internal membrane opens under water pressure to allow free discharge, then automatically closes to form a tight seal that prevents foul odours and sewer gases from entering the building. Ideal for use with pressure relief valve discharges on unvented domestic hot water systems, it contains no water seal so it cannot dry out through evaporation or infrequent use. Maintenance access is required, and it is not recommended for installations where this is not available.