Closed systems recirculate the same water continuously. Because contaminants remain trapped inside the loop, water quality is critical.
Best practice includes:
High-velocity flushing during commissioning
Chemical cleaning where required
Correct inhibitor dosing
Routine monitoring and water testing
Open systems are exposed to air and external contaminants, requiring more active water treatment.
Typical requirements include:
Continuous chemical dosing
Biocide programmes for bacterial control
Scale and corrosion management
Frequent monitoring
Effective flushing requires planning and technical execution.
Key principles include:
Achieving sufficient flow velocity to remove debris
Flushing in stages or sections where necessary
Installing temporary strainers or filtration equipment
Monitoring water clarity and contamination levels
Recording results for commissioning documentation
The goal is not simply moving water — it is removing contamination to achieve defined cleanliness standards.
Successful dosing strategies focus on long-term system health.
Recommended approaches include:
Accurate calculation of system volume
Selecting chemicals compatible with system materials
Testing baseline water chemistry before dosing
Verifying inhibitor levels after treatment
Establishing ongoing monitoring and maintenance schedules
Overdosing or incorrect chemical selection can cause as many problems as inadequate treatment, so specialist input is valuable.
Many long-term system issues stem from avoidable commissioning errors:
Flushing at insufficient flow rates
Skipping chemical cleaning stages
Not testing water chemistry after dosing
Assuming one-time treatment is sufficient
Failing to implement ongoing monitoring
Treating flushing and dosing as critical engineering processes — rather than final check-box tasks, dramatically improves outcomes.
Investing time in proper commissioning delivers measurable benefits:
Improved system efficiency and energy savings
Reduced maintenance and repair costs
Extended equipment lifespan
More stable and predictable performance
Lower risk of downtime
For building owners, contractors, and facilities managers, these benefits translate into reduced lifecycle costs and more reliable building services.
Flushing and dosing pipework are fundamental steps in delivering high-performance HVAC and building services systems. By removing contaminants early and maintaining water quality over time, you protect both equipment and investment.
The difference between a system that performs well for decades and one that develops ongoing issues often comes down to the quality of its initial cleaning and treatment.
Clean systems simply work better.
