Understanding controls

Controls and control systems are an essential part of buildings, from the simple switching on and off of equipment to sophisticated building management systems that monitor and optimise plant performance to meet building needs. Nowadays it is impossible to avoid the use of control systems, which necessitates some knowledge of what they do, and how they function, in order to be able to ask for the right level of control in the first place and to operate the controls successfully.For example, domestic heating systems commonly use time clocks and temperature controls, often electronic ones which will require programming and adjustment by the user to meet their specific needs. Many people are unaware of basic control functions and, in consequence, can use controls incorrectly — for example by using a thermostat (automatic temperature control) as an on/off control for their systems. Who has not come into the house when it is cold and turned the thermostat up 'till it clicks'? The problem for building users and operators is more acute as they will have much more complex systems to operate and, for new projects, they will have to explain, or even specify, their operating needs and requirements for the building control systems.Whilst there are many experts who can advise on suitable control systems, some of the jargon and terminology used in controls engineering can seem impenetrable and incomprehensible to the non-expert, which can make it difficult to have a useful and constructive discussion of user needs and required functions. Experience suggests that many buildings do not work as well as intended or meet occupant needs satisfactorily with, in many cases, the cause being control problems.