DA24 Hydronic System Balancing – in HVAC

DA24 Hydronic System Balancing – in HVAC is a revised and updated Design Application (DA) manual in AIRAH’s collection of technical resources. The previous version of this technical resource was titled DA24 Water Systems Balancing.

This DA manual discusses the testing, adjusting and balancing (TAB) of hydronic water systems in heating, ventilation, air conditioning and refrigeration (HVAC&R) applications.

The primary purpose of this manual is to promote best practice for the balancing of hydronic systems in HVAC&R, recognising acceptable industry-standard techniques to be used in the implementation of TAB. It also highlights the importance and complexity of hydronic balancing, which is often underestimated by many stakeholders.

Why is this topic important?

During commissioning, the accurate measurement and adjustment of water flow rates using a recognised and reliable process ensures that plant and equipment are adjusted and set correctly to meet the specified design operating conditions.

A good working knowledge of the fundamentals of hydronic system balancing should underpin the skills of HVAC&R system designers, installers, operators and maintainers to ensure that the TAB process is carefully considered at each stage of a construction – from concept design through to operation. 

Released in June 2021, DA24 covers:

  • Commissioning and TAB – an overview
  • Fundamentals of water flow
  • Measuring water flow
  • Preparing and programming for TAB
  • Water balancing TAB procedures
  • Components and TAB
  • The systems approach 
  • Recording and reporting.

DA24 is designed for:

This mannual has been prepared to provide both theoretical and practical knowledge to help assist those involved in the process of testing, adjusting and balancing water systems within the HVAC&R industry. This includes engineers, architects and contractors, as well as equipment owners, operators and specifiers.

It has been designed to provide a complete overview of water-side HVAC TAB techniques, as well as specific information for an understanding of the fundamental science behind the TAB process and an appreciation of the systems approach and perspective to TAB.

The manual also provides guidance on how to manage many of the practical issues encountered when implementing water-balancing procedures in hydronic HVAC distribution systems.

DA24 release schedule

  • May 3, 2021 – Hard copy pre-order pricing begins
  • June 1, 2021 – Regular pre-order pricing begins; digital release of DA24
  • June 3, 2021 – Hard copy release (coinciding with the Commissioning Virtual Forum)


  AIRAH members  Non-members
Digital access
Hard copy
$79 $229
Hard copy package
(DA04 + DA24)
$118 $418

GST included

Access the digital version  |  Order a hard copy

For more information about downloading DA Manuals on Adobe Digital Editions, please click here.

You can also save on your hard copy order of DA24 when you bundle it with DA04 Air System Balancing – in HVAC. Please click here for more information on this package.

About DA24

Many heating, ventilation and air conditioning (HVAC) systems use heated or cooled water to provide comfort conditions within buildings. Owners, managers and operators rely on these hydronic systems to operate their buildings, to support their processes, or to enable other systems.

Hydronic systems in HVAC are designed to deliver pre-calculated amounts of heated or cooled water down sometimes complex piped distribution systems, all controlled by dynamic and responsive comfort controls. To have any chance of performing as the designer intended, these systems must be tested, adjusted and balanced (TAB) after installation – and, importantly, the water distribution quantities must be measured, adjusted and verified against the design. TAB is the process of making an HVAC system perform as efficiently as the designer intended, and it helps HVAC systems operate more effectively, providing maximum comfort at the lowest energy cost possible.

The performance of any equipment in centralised HVAC systems is dependent on many parameters, but sufficient water flow is one of the most significant.

To understand the best way to approach a system water balance, the TAB technician must understand how the system is intended to operate. This knowledge transfer is the responsibility of the system designer, and it is important that the designer clearly communicates the intended operation and performance of the system, and how it is to be verified.

This is the starting point of the TAB process.

This DA manual considers the entire water-balancing story. Starting from an explanation of where TAB sits in the overall commissioning process, the manual takes us through the fundamentals of water flow and measurement, what needs to be done before TAB, how to approach a water balance for a range of different system types, and what to do after the water balance has been successfully completed, including recording and witnessing results.

The TAB technician should provide a detailed diagnostic report, with all readings and settings clearly documented. This provides the system owner with an excellent working knowledge of how their systems should run and what parameters to check in the future.

Taking a holistic approach to how buildings and systems operate is a key component to system efficiency. Small adjustments and repairs that represent a minor expense at TAB stage can have a large impact on system return on investment. Poorly balanced systems may not always achieve comfort, will cost more to run and will have a reduced equipment working life.

The intention for this manual is to help industry standardise the way a water balance is performed, with a strong focus on the application of best practice to minimise the impact the water balance has on the ongoing energy efficiency and energy consumption of the system.

TAB is not just a verification hoop that the system has to pass – the focus is not just to “make the system work” – it is an essential part of the commissioning process where an inanimate collection of objects is brought to life as a dynamic operating system and set to work as intended. The focus is the overall system as well as the individual components.

This application manual, now in its second edition, is the definitive reference for HVAC water balance in Australia. It is designed for, and used by, the TAB technician, but can also be used by HVAC system designers and installers to understand their roles in the process. Anyone involved in water balancing or in HVAC&R system commissioning/recommissioning should keep a copy of this manual handy.

This page was last updated July 22, 2021