To meet the Government’s target of an 80% reduction in carbon emissions by 2050 and the increased demand for retrofit faced by the industry, it is no surprise we are consistently seeing modern condensing or high efficiency boilers installed on older heating systems. Russ Walliss, Service Manager at Hamworthy Heating explains why consideration needs to be taken into account when embarking on the refurbishment of plant rooms and heating systems, particularly the quality of the water within the system.
All too often we visit a site for commissioning or to investigate an issue only to discover that there has been no water treatment or measures put in place to protect the system. We recommend that water treatment and subsequent analysis is carried out on every system prior to installation and regularly thereafter, as any debris in the system could end up counteracting the increased efficiency of the newly installed equipment.
Regular analysis will also help identify if system treatment has been diluted, by auto-system make-up, where a leak may have gone unnoticed. Plus, preventative measures are much less costly than rectifying a system that has failed as a result of poor water quality.
Safeguard capital investment
Boilers can count towards a significant proportion of the capital investment of a project and the debris and oxides found in old heating systems can have serious adverse effects on new products. When metals meet with the oxides found in certain waters they cause a chemical reaction that can result in corrosion; the pH level of the water and the material used in the manufacture of the heat exchanger dictates the rate at which this corrosion will occur.
A build-up of sludge (from corrosion) and hydrogen gases can also take place in the heating system itself, such as in the radiators which, if left to accumulate, will increase system resistance and impact the flow of water, raise the noise level of the heating system and even result in burst radiators causing damage to the building.
Maintaining efficient operation
A system that is harbouring a build-up of corrosion and sludge will have to work harder to distribute the water and heat. Blockages and sludge will impact the water flow resulting in certain mechanical components having to work harder as they are fighting against the obstruction.
Increased operation of components such as the heating system pump will result in higher energy consumption and mean they are likely to perish at a faster rate and could need servicing or replacing sooner than expected; an unplanned maintenance cost that will have to be met.
With ever increasing energy bills it is essential to avoid overpaying for your gas and electric. Just a 1mm layer of limescale build up on the heat exchanger can reduce the efficiency by 7.5%. Before the heat can even reach the water it has to pass through this layer of scale; more fuel is used due to the reduced heat exchanger conductivity and the heating circuit will take longer to reach the required temperature.
These issues are not evident in every system and the degree of their effect on the plant in the system varies; some constituents in the water can even be beneficial. Hard water areas, for example, present different challenges to soft water areas and consideration should always be given to the age and condition of the system.
Even new systems require a level of treatment to clean the heating circuit and clear any contaminants that may have appeared as a result of the product manufacture or installation including flux residues, greases, debris, swarf and minerals that need removing prior to the corrosion inhibitor being added.
There is not a ‘one method suits all’ solution to water treatment. We often hear the myth that stainless steel boilers don’t require water treatment as the metal is more resistant to corrosion. This is not the case. Stainless steel corrodes – just at a different rate and pH level to other materials. Plus, the element chloride is extremely detrimental to stainless steel in particular. We are able to analyse the water for the composition of a number of elements including hardness, conductivity, acidity, chlorides, iron, copper and aluminium and provide a report and recommendations for improvement if needed.
Water treatment should be carried out as standard at any initial system set up and must be tailored to the type of boiler; materials used to construct the system (pipework, storage tanks etc); age of the system and supply/make-up of the water.
Before installing boilers and heating equipment, systems must be flushed thoroughly; first with clean water, and then with a chemical cleaning solution to clear any debris and ensure system cleanliness prior to filling with an inhibitor to protect the system in the longer term.
Despite taking the correct measures to clean and protect a system with an inhibitor you cannot guarantee that all detrimental dirt accumulations are removed. This is where the addition of an air and dirt separator can offer added assurance. Providing a dual function, they collect and remove dissolved gases from system water through an automatic air vent at the same time as trapping dirt particles that can be removed periodically through a flushing valve.
With an older system it may be advantageous to totally separate the boilers from the secondary circuits by using a plate heat exchanger. This method of connection prevents system debris/contaminates entering the boiler. This is not a replacement for water treatment as the system will still need to be flushed and protected by an inhibitor but it does help to safeguard the boiler plant from the effects of debris and harmful compounds found in existing systems.
Prevention is better than cure
As well as being a condition of most manufacturers’ warranty, tailored water treatment can ultimately prolong the life of your boiler, maintain optimum efficiency of your heating system and reduce the likelihood of breakdowns and unexpected repair costs.
It is an on-going regime that does not stop once the boilers have been installed, and as boilers become even more sophisticated so do the supporting ancillaries to ensure the system is clean and protected to maximise efficiency.