HVAC water system monitoring for FMs – what do we monitor and why?

6th August 2021

Monitoring is a critical part of our closed-circuit water treatment services.  These systems are crucial to overall HVAC performance, but they are vulnerable to corrosion and scale, in many cases leading to poor performance and high costs.

Real-time monitoring technology protects expensive HVAC assets and reduces risk by continuously monitoring the parameters that cause corrosion, allowing FMs to take a preventative approach to HVAC water treatment.

What is real-time monitoring used for?

  • Precommission cleaning – continuous monitoring at this stage reduces uncertainty at handover and increases accountability, as issues can be pinpointed to a specific time.
  • One-off health check – corrosion monitoring technology can be installed on site for a fixed period – anywhere from two weeks to several months.  With instantaneous access to critical data, FMs can ensure the system returns to a stable condition as soon as possible and effective treatment if sought.
  • Ongoing maintenance – alternatively, the technology can be installed as a long-term solution to ongoing HVAC maintenance.

How does real-time data inform water treatment?

The starting point of any water treatment programme is to ensure that the system is as clean as practically possible.  If FMs can refer to real-time data, they can make informed and appropriate water treatment decisions based on accurate information.

Water Treatment can be designed to be specific and efficient, rather than as a knee-jerk reaction. Flushing, for example, is often undertaken as a matter of routine but it can lead to damage and unnecessary degradation.  In many cases, more sustainable methods can be used, including side stream filtration and non-chemical treatments, which are less invasive and reduce chemical and water requirements.

The core principle of this approach is that cumulative data informs active service interventions.  Monitoring technology tracks parameters which indicate a risk of corrosion, rather than the corrosion itself, ensuring energy use is optimised, plant life if prolonged and costs reduced.

What parameters should FMs monitor?

The most important corrosion causing parameter is Dissolved Oxygen (DO) – something that is not flagged up by sampling or corrosion coupons.

DO is the precursor to all corrosion in closed circuit water systems.  If left unchecked, debris can build up in pipes and components causing a whole host of problems, including reduced performance of heat exchangers, changes in flow characteristics, leaks and general degradation of pipework and components.

Hevasure monitors DO alongside:

  • Pressure – Ensure the system is air-tight, indicating oxygen ingress – particularly important following planned activities such as flushing.
  • pH – a change in pH could be the first sign of problems with the water chemistry.
  • Temperature – to ensure a system is operating effectively.
  • Steel corrosion rate – measuring galvanic currents in proportion to DO and temperature indicates whether inhibitors are working correctly.
  • Inhibitor/glycol concentration – chemical treatments are an essential part of closed-circuit system maintenance but to achieve optimum performance and sustainability a balance is required.  Real-time access to inhibitor concentration levels gives FMs more control over water treatment products, reducing chemical wastage and costs.
  • Crevice corrosion – early indication of this subtle but highly damaging form of corrosion means swift action can be taken on problem areas.

Contact our team of experts today to find out more about our water treatment and monitoring services for Facilities Managers.