Return Valve SIMFER 125 mm — inlet/outlet check valve, Ø125

SIMFER return valve with a nominal diameter of 125 mm is a one-way inlet/outlet check valve designed to prevent backflow in ventilation and duct systems. The valve fits ducts with Ø125 connections and is intended for installation in air supply, exhaust lines and appliance outlets where controlled, one-directional airflow is required. Its compact design allows integration in domestic and commercial ventilation and HVAC systems to maintain proper air movement and prevent reverse air entry.

Advantages

The SIMFER Ø125 check valve provides reliable prevention of backflow with a simple mechanical flap that opens under forward airflow and closes when flow reverses. Its construction is suitable for standard circular ducts with 125 mm diameter, enabling straightforward installation and replacement. The valve requires no external power, operates silently under normal conditions and contributes to maintaining indoor air quality by preventing unwanted air ingress and odor transfer.

Suitable for

• Residential ventilation ducts with Ø125 connections
• Bathroom and kitchen exhaust lines
• HVAC exhaust and intake sections in small commercial spaces
• Appliance outlet connections where one-way airflow is required

Key specifications

• Nominal diameter: 125 mm (fits Ø125 ducts)
• Function: one-way check/return valve for air flows
• Application: ventilation, exhaust, duct systems
• Operation: passive mechanical flap; no external power required
• Installation type: inline connection for circular ducts

How to use

Install the valve into a circular duct section with a 125 mm internal diameter, ensuring the flap faces the direction of intended airflow so it opens under normal operation and closes when reverse flow occurs. Secure the valve using appropriate duct connectors, clamps or sealant compatible with the duct material to prevent leaks. After installation, verify that the flap moves freely and that there are no obstructions or misalignments that could impede operation.

Usage recommendations

For reliable performance, inspect the valve periodically for dust buildup, debris or mechanical wear, and clean or replace the unit if the flap does not seal or move freely. Use in environments within typical residential and commercial ventilation temperature and humidity ranges; avoid exposure to corrosive gases or particulate loads beyond standard ventilation conditions. When integrating into HVAC systems, confirm compatibility with ductwork and airflow rates to ensure the check valve does not create excessive pressure drop.