What is a Zone Valve?

A zone valve is a control device that opens, closes, or modulates water flow through the coil or terminal unit serving a defined area of a building. Zone valves play an important role in hydronic HVAC systems because they regulate water flow for a specific room or zone, allowing the system to respond to the heating or cooling demand in that area.

How does a zone valve work?

A zone valve works by receiving a control signal and opening or closing the valve to regulate how much water passes through the circuit to maintain the desired setpoint. In a zoning application, that means matching water flow to the needs of the specific room or zone being served rather than sending the same flow everywhere. 

What is the difference between pressure-dependent and pressure-independent zone valves?

The main difference is how the valve responds when system pressure changes. A pressure-dependent zone valve does not compensate for those pressure changes on its own, while a pressure-independent zone valve is designed to maintain the intended flow regardless of pressure fluctuations. In the Belimo ZoneTight line, the QCV is the pressure-dependent option, available as an ultra-compact 2-way or 3-way zone valve. The PIQCV is the pressure-independent option, combining a differential pressure regulator with a 2-way control valve to maintain specific flow and provide balancing and control in one unit. Both ZoneTight options are designed for tight spaces and include self-cleaning ball valve technology and field-adjustable flow. The QCV is designed for zero leakage and low power consumption, while the PIQCV is designed for pressure-independent flow with balancing and control in one unit.

Why choose a Belimo ZoneTight valve?

A Belimo ZoneTight valve fits best when an application calls for a compact form factor, low power draw, tight shutoff, or field-adjustable flow to meet design requirements. It is especially well suited to tight spaces where space is limited and efficient zoning control matters. Features such as zero leakage, self-cleaning ball valve technology, and field-adjustable flow make it a practical choice for applications where energy performance, reliability, and simple commissioning are priorities. 

When is a pressure-independent zone valve the better choice?

The PIQCV is the better choice when maintaining design flow despite pressure fluctuations is a priority. This is especially helpful in buildings working to meet energy efficiency targets, because stable flow control supports system performance and reduces wasted energy.  Because it combines balancing and control in one unit, with flow adjustable at the actuator, the PIQCV reduces the need for separate balancing work during installation and commissioning and helps avoid rebalancing if a new circuit is added later.

How should a Belimo ZoneTight valve be selected and adjusted?

ZoneTight valves are designed to make flow selection and adjustment more straightforward. With SelectPro, you can select the valve model and set the desired Cv and Delta P for pressure-dependent valves or GPM for pressure-independent valves. ZoneTight valves also offer field-adjustable flow to meet design requirements, which helps make commissioning, retrofit work, and tenant improvements easier.

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