Why Monitor Closed-Circuit Water Systems?

Corrosion costs

The cost of closed-circuit water system breakdown due to corrosion can run into the millions, resulting in expensive repairs, downtime and reputation damage. By identifying the conditions that lead to corrosion and subsequent system failure, Hevasure’s water monitoring technology allows M&E contractors and facilities managers to find the root cause of a problem and fix it before it becomes more serious.

For specifiers and building owners, monitoring water make-up from the outset and throughout a closed circuit system’s life, ensures design life is achieved, efficiencies are maintained and downtime is avoided.

Corrosion significantly impacts the performance of water reliant piped services in a number of ways:

Debris build up in a pipe
Build-up of debris in pipes and components causes restriction, which can lead to increased pump energies in order to maintain flow rates.
Debris on a heat exchanger
Heat transfer is reduced as a result of corrosion debris on heat exchangers and emitters.
Corroded valve
Valve seats can be eroded, leading to changes in flow characteristics.
Leaking pipe
Heavily degraded pipework and components will eventually leak.

What does Hevasure monitor?

Hevasure’s intelligent water monitoring technology checks a range of parameters in order to get a real-time view of system integrity, water characteristics and corrosion. Suitable for use on closed-circuit systems of any size, the unit prevents corrosion and system breakdown by flagging up small changes in condition that would lead to more serious (and expensive) issues if left unchecked.

Common applications include commercial premises, in both the public and private sector, district heating systems, data centres and hospitals. The unit can be used to monitor conditions at all stages of a water system’s life, from pre-commissioning cleaning through to handover and on-going maintenance.

Importantly, our state-of-the-art sensors check for Dissolved Oxygen (DO), something that is not picked up by sampling – the traditional way of checking water condition. DO is the pre-cursor to nearly all types of corrosion, directly resulting in pipe and component degradation and/or providing the right conditions for bacteria to thrive, which can lead to Microbial Induced Corrosion (MIC).

Detecting oxygen’s presence, along with the parameters that cause it to enter systems, such as pressure or make-up water flows, is critical.  Measuring other contributory factors - pH, inhibitor levels and temperature - provides a full picture.

Intelligent corrosion control

The capturing of real-time data is just the beginning. To truly prevent corrosion, it's important to understand how these parameters effect a system and what this data means.

Our cutting edge technology includes propriety algorithms and intelligent interpretation in order to understand the interplay between different readings and what these readings signify.

The latest version includes a BACnet interface which integrates Hevasure data with the BMS, allowing site managers to oversee active service interventions, minimising the risk of failure while eliminating unnecessary and costly site visits.


Dissolved oxygen

Dissolved oxygen:
Dissolved oxygen is the main driver of corrosion. By measuring DO we can identify whether the system is air-tight and check how quickly base-levels are returned to following the introduction of fresh aerated water.
Pressure Gauge


A closed system must maintain a positive relative pressure at all times to avoid air being sucked into the system. We monitor pressure at all times to check if pressurisation units and expansion vessels are correctly set-up and maintained.


For systems containing aluminium the pH must not exceed 8.5; the point at which passive films could break down and aluminium components, such as heat exchangers, can start to corrode. Changes in pH also indicate potential problems with the water chemistry.
Steel Corrosion Rate

Steel corrosion rate

Steel corrosion rate:
Our patented galvanic current sensor allows us to determine the rate of corrosion of steel (expressed in mm per year). In uninhibited systems galvanic currents increase in proportion to DO and temperature. However, inhibitors, when at the correct dosing level, passivate metal surfaces, suppressing corrosion and galvanic currents. This provides us with an easy way to determine if inhibitors are behaving effectively under operating conditions.
Crevice Corrosion

Crevice corrosion

Crevice corrosion:
Crevice corrosion is a particularly insidious form of corrosion leading to rapid pitting attack and pin-holing. It occurs in localised regions such as weld seams and under debris where a micro-environment can be formed. Our unique and patented sensor provides early indication of crevice corrosion
Water Leak

Leaks (water make-up volume)

Leaks (water make-up volume):
By measuring water make-up volume, leaks in the system can be identified and planned flushing activities can be monitored.
Water Temperature


We measure temperature to ensure that the system is operating as intended.
Water Glycol

Inhibitor/glycol concentration

Inhibitor/glycol concentration:
Under-dosing with chemicals can adversely affect corrosion and performance. Conversely, over-dosing wastes money and is bad for the environment. By measuring conductivity, we can advise whether the concentration of water treatment products is within recommended levels.

Real-time response

Readings are captured 24/7 and viewable on an interactive dashboard, allowing for an accurate picture of water condition – during pre-commission cleaning and ongoing operation. If any parameter exceeds critical levels, alarms are instantly raised (via emails and text), allowing for swift reaction to stop corrosion in its tracks.