Are There Special Valves Required for Closed Loop Systems?

System Requirements

In a solar hot water drainback system, a check valve is essential to prevent antifreeze from flowing back into the solar collectors during the drainback process. These valves are usually 3-way or 4-way check valves, which allow the system to drain and then refill with antifreeze. A 3-way check valve can cost between $50-$100, while a 4-way check valve can range from $100-$200.

Drainback Valve Selection

When selecting a drainback valve, consider the system’s pressure rating, flow rate, and temperature range. For example, a Grundfos UV 15 is a popular check valve for solar drainback systems, with a pressure rating of 3 bar and a flow rate of up to 15 liters per minute. Always choose a valve that meets or exceeds the system’s requirements to ensure safe and reliable operation.