Differential pressure control valve

Test Method for PICVs and DPCVs (BTS 1/2019), published by BSRIA in November 2019, defines a differential pressure control valve (DPCV) as: ‘A valve that operates to maintain constant differential pressure between two points that is, within limits, independent of the supplied differential pressure. The valve may operate mechanically or electronically.’

The Illustrated Guide to Mechanical Building Services, Third Edition (BG 31/2017), by David Bleicher, published by BSRIA in 2017, suggests that differential pressure control valves (DPCVs): ‘…are installed on variable flow systems to ensure that the differential pressure across a two-port valve does not exceed a set limit. This in turn limits the flow to a set value in the sub-branch, maintaining the control authority of the two-port valve.’

Test Method for Heat Interface Units (BTS 2/2015), written by Colin Judd, and published by BSRIA in December 2015 and amended in June 2016, states: ‘A differential pressure control valve (DPCV) operates to maintain a constant differential pressure between two points in a heating or cooling circuit that is, within limits, independent of the supplied differential pressure. A DPCV is normally used in conjunction with a regulating valve and a flow control valve.’

Energy Efficient Pumping Systems, a design guide (BG 12/2011), written by Chris Parsloe and published by BSRIA in 2011, states: ‘A DPCV is a self-acting valve that acts in response to changes in pressure differential between its inlet port and a position somewhere upstream in the pipework system. These two pressures are transmitted to either side of a flexible diaphragm inside the valve via small capillary tubes. As the diaphragm flexes in response to the changing pressure differential, it causes the valve plug to move thereby varying the opening through the valve. The effect is to maintain a constant pressure differential between the inlet to the valve and the upstream point to which the capillary tube is attached. The pressure setting can be varied, but once set, the action of the valve will hold it constant regardless of changes in the resistance of the circuit and regardless of changes in the available pump pressure.'

Selection of Control Valves in Variable Flow Systems (BG 51/2014) written by Chris Parsloe and published by BSRIA in June 2014, defines a differential pressure control valve (DPCV) as: ‘..a self-acting valve that maintains a constant pressure differential between two points (for example, across the flow and return pipes in a pipework branch). The controlled pressure differential can be varied but, once set (and provided the valve is operating within its recommended range) the action of the valve will hold it relatively constant regardless of changes in the controlled circuit and regardless of flow and pressure changes in the system to which the controlled circuit is connected. DPCVs are typically used in conjunction with branches serving room terminal devices controlled by 2PVs or TRVs. The DPCV protects the control valve from fluctuating pressures, thus maintaining control valve authority and ensures the 2PVs / TRVs do not need to close against excessive pressure differentials.’

--BSRIA

[edit] Related articles on Designing Buildings

• Actuator.
• BSRIA.
• BSRIA articles on Designing Buildings Wiki.
• BSRIA launches updated Valve Test Standard.
• BSRIA publishes new edition of BG29.
• Flow characteristic.
• Pipework.
• Pressure independent control valves.
• Pressure-relief valve.
• Radiator.
• Tap.
• Valves.
• What makes a good PICV?