Chapter 22 Building Automation System Retrofit of Existing Systems Retrofit Stages • Rooftop Packaged Unit Retrofit Application • Variable Air Volume Air Handling Unit Retrofit Application • Variable Air Volume Terminal Box Controller Retrofit Application • Boiler Control Retrofit Application • Chiller Control Retrofit Application • Special Retrofit Situations

Competencies List and describe common stages of the retrofit process. Identify common applications of the retrofit process.

Stages of the retrofit process building survey, documentation, and planning existing control removal new building automation system installation programming and commissioning human-computer interface setup ongoing support A retrofit is the process of upgrading a building automation system by replacing obsolete or worn parts, components, and controls with new or modern ones. A retrofit can be broken down into distinct stages: building survey, documentation, and planning; existing control removal; new building automation system installation; programming and commissioning; human- computer interface setup; and ongoing support. The building survey, programming documentation, and materials list are developed. Figure 22-1. The existing control system is removed. Figure 22-2. In many cases today, the installation of the components is performed by qualified subcontractors. Building automation system programming involves creating software for the individual controllers and operator interface devices. Commissioning is the checkout procedure used to start up a new building automation system. The human-computer interface is installed as part of the building automation system. After the building automation system installation is complete, final as-built drawings and other documentation are provided to the customer, training is scheduled, warranty dates and parameters are set, and long-term maintenance agreements may be signed and implemented.

Retrofit applications rooftop packaged unit variable air volume air handling unit variable air volume terminal box controller boiler control chiller control old building automation systems new mechanical equipment The control system of a common rooftop packaged unit, such as a 10-ton, two-stage cooling, single-stage gas heat unit, may be retrofitted to a building automation system. Figure 22-4. A common variable air volume air handling unit retrofit application is retrofitting an existing pneumatic control system to a building automation system. Figure 22-7. A common retrofit application is retrofitting the controls in each zone to a building automation system with the controller mounted on the VAV terminal box. Figure 22-10. A boiler control retrofit application normally consists of retrofitting an existing electromechanical boiler control system to a building automation system. A common chiller control retrofit application is the retrofitting of the pneumatic control system of an old centrifugal chiller with a building automation system. Figure 22-13. Common retrofit applications include the retrofitting of an old building automation system to a new system, and retrofitting of new mechanical equipment with microprocessor control panels to a building automation system. Figure 22-14.

Chapter 22 Review What does a building survey contain? inventory of energy-consuming equipment in a building What is a human-computer interface? central computer that allows staff to view the operation of the building automation system A building survey is an inventory of the energy-consuming equipment in a commercial building. A human-computer interface (HCI) is the central computer that enables the building staff to view the operation of the building automation system.