Choosing the Right Heat Pump Diverter Valve

Air Source Heat Pumps operate at low water temperatures and require a high flow rate for optimal performance. Selecting the correct diverter valve is essential to ensuring efficiency, reliability, and longevity in your heat pump system.

Why Standard Diverter Valves Fall Short

Traditional heating diverter valves, commonly used for domestic hot water cylinders in the UK, are typically of the 'spring return' type. These valves generally operate with a Kv value of around 9, which may not be adequate for air source heat pump systems.

The Kv value represents the amount of flow in a regulating valve at a given valve position with a pressure loss of 1 bar. The specific case of a fully open valve is represented by the Kvs value.

Understanding Kv and Kvs Values

The flow rate (Kv) can be calculated using the following formula:

Kv = Q / √ΔP

Where:

• Kv: Flow coefficient [m³/h]

• Q: Flow rate [m³/h]

• ΔP: Pressure loss across the valve [bar]

The Kvs value, meanwhile, represents the flow in a fully open valve with a pressure differential of 1 bar. This distinction is vital when choosing a diverter valve for an air source heat pump system.

Why You Need a High Kv Diverter Valve

Given the high flow rate required by air source heat pumps, a suitable diverter valve must be selected to prevent inefficiencies, pressure loss, or premature system failure. Standard diverter valves with low Kv values and weak torque actuators are not built to handle these demands.

The Ideal Solution: ESBE VRG231 Diverter Valve

For air source heat pump systems, we recommend the ESBE VRG231 diverter valve, paired with the ARA656 actuator. This combination provides:

• A high Kv value to accommodate the required flow rate

• A durable, high-torque actuator for consistent and reliable performance

• Compatibility with leading heat pump brands such as Vaillant and Daikin

Conclusion

Selecting the right diverter valve is crucial for maximizing efficiency and ensuring the long-term reliability of an air source heat pump system. The ESBE VRG231 valve, combined with the ARA656 actuator, is a proven solution designed specifically to meet the high flow demands of modern heat pump installations.