Four-port control valve
Selection of Control Valves in Variable Flow Systems (BG 51/2014) written by Chris Parsloe and published by BSRIA in June 2014, defines a four-port control valve (4PV) An actuated control valve with four ports (two inlet and two outlet) which varies flow through a terminal device by diverting a proportion of the flow through an integral “restricted” bypass avoiding the need for a separate piped bypass… Four-port valves are always designed as mixing valves but are commonly used in diverting applications.
It suggests that typical applications include; modulating control of heating and cooling, outputs from small fan coil units or chilled beams (typically up to a 20 mm pipe size) in constant flow branches.
--BSRIA
[edit] Related articles on Designing Buildings
Featured articles and news
We're expanding our collaborative mission by launching DB Intelligence, an exclusive market research advisory panel. Built environment professionals can now get paid to share their expertise on industry trends, products and services.
Panel members receive direct financial incentives for participating in research projects like short surveys, 1-2-1 interviews and focus groups. Register today to shape the future of the construction sector.
Building Control Independent Panel final report
A precis of a key report led by Dame Hackitt with full recommendations and link to the government response.
Guide to ISO 19650 for Architecture Firms (2026)
A user gives their low down.
A UK training and membership provider for mould remediation professionals.
Building Safety recap April, 2026
A short and longer run-through of the month, with links to further information and sources.
CIAT May 2026 briefing.
Independent NSI and BAFE study exploring how organisations are changing the way they buy fire safety services.
From medieval scribes to modern word art.
ECA welcomes crackdown on late payment and push for clean energy, whilst CIOB seek fixed cladding removal timeframes.
Cyber Security in the Built Environment
Protecting projects, data, and digital assets: A CIOB Academy TIS.
Managing competence in the built environment
ITFG publishes new industry guide on how to meet the ICC principles.
The UK's campaign to reduce noise pollution: Mythbusting, articles and topic guides.