Danfoss AB-QM Balancing Valve

Danfoss AB-QM Flow Limiting Valves

The AB-QM valves are flow-limiting valves designed for heating systems, providing precise control of both flow and temperature. By regulating flow to a pre-set scale, the internal diaphragm maintains a low pressure differential, ensuring the flow does not exceed the set point. This prevents pump overflow, maintains stable room temperatures, and improves system efficiency, ultimately reducing heating costs and installation complexity.

Key Features and Benefits

• Efficient Flow Control – Maintains constant flow to avoid temperature fluctuations and energy waste
• Cost Savings – Reduces installation costs and optimises energy efficiency for end users
• Connection Sizes – 40–50mm with union connections; 65–250mm with PN16 flanged connections
• Pre-Set Flow Ranges – Each valve size has predetermined flow settings for accurate system balancing
• Hydronic Balancing – Controls flow in heating and cooling circuits without overflow

Pressure Independent Control (PICV) Upgrade

The AB-QM can be converted into a Pressure Independent Control Valve (PICV) with the addition of an actuator. Danfoss offers four actuator types:
• On/Off
• 0–10V
• 4–20mA
• Floating point

Adding an actuator transforms the AB-QM into a full-authority valve capable of controlling heating and cooling circuits for Air Handling Units (AHUs) and Fan Coil Units (FCUs). This eliminates the need for multiple valves, streamlining installation, reducing costs, and maintaining precise hydronic balance.

The AB-QM series provides a reliable, energy-efficient solution for modern heating and cooling systems, combining flow limiting, temperature control, and optional pressure-independent operation in a single device.