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Closed Recirculating Systems

Closed recirculating systems come in many forms but generally provide heating or cooling for all types of buildings.

A properly maintained system uses less energy and heat production and transfer is efficient and maintaining the re-circulating water correctly is crucial in order to extend the life of a system by minimising microbiological problems, corrosion and unwanted build-up of scale and other deposits.

Types of System

  • LTHW – Low Temperature Hot Water Systems terminal units.
  • CHW – Chilled Water Systems
  • Runaround Coils
  • Condenser Systems
  • MTHW/ HTHW – Medium and High Temperature Water Systems

Pre-commission Cleaning of Pipework Systems

Goodwater began life as a flushing company dedicated to providing pre-commissioning chemical cleaning services to mechanical system installers. Over the years various guides have been written by BSRIA (the Building Services Research & Information Association), the latest being BG 29/2021, explaining how new and extended closed re-circulating systems should be cleaned to ensure they can be successfully commissioned and that they start their operational life free from debris, corrosion and bacteria.

We tailor our water treatment programmes with as many stages as are necessary to suit the requirements of the project and the specifications. Typical programmes may include:

  • Preliminary sampling (microbiology and chemistry) of proposed water supply and the system – to determine water quality and confirm the required programme of works.
  • Dynamic flush – to remove debris.
  • Biocide wash – to reduce or remove bacteria (i.e. biofilm).
  • Chemical clean – to remove surface oxides, grease, oil and flux and prepare surfaces for passivation.
  • Application of final treatments for ongoing protection – corrosion inhibitor, biocide and maybe antifreeze (for chilled systems).
  • Ongoing system sampling (microbiology and chemistry) from completion to the point of handover and beyond if required.
Closed Re-circulating Systems - BANNER


After handover, the system moves into its operational phase, and the water treatment must continue otherwise treatments may dwindle, and if that happens the likelihood of microbiological issues increases and the system may start to corrode meaning system components may become susceptible to failure and we provide all necessary chemicals and testing.

Our skilled service engineers are fully trained and equipped to undertake regular analysis and dosing of systems following guidance given in BSRIA BG50/2013. We use state-of-the-art on-site photometer testing equipment and have an array of laboratory services to complement our testing programmes.

We also supply a wide range of corrosion inhibitors, biocides and antifreeze treatments to ensure that correct conditions are always maintained, thereby extending the lifespan of the system.

We can also offer remedial system flushing and treatments to correct historical issues, and our equipment range includes filtration and also manual and automatic chemical dosing plant to make system maintenance even easier.