Water quality is the key factor for optimum performance and system longevity in both domestic and light commercial heating installations. Martin Wilkinson, Spirtoech UK’s National Sales Manager Commercial, looks at the benefits of a ‘fluid first’ approach.
Martin Wilkinson, National Sales Manager Commercial for Spirotech UK
The design stage is key for a light commercial heating system, regardless of the installation, whether it’s an office block, school or retail facility. Specifiers are now more selective about the suppliers and products that they use, prompted, in part, by the quality and efficiency of modern boilers and their component parts.
Modern systems are the polar opposite of the cast iron, highly inefficient products traditionally installed in light commercial environments. Today’s boilers are more efficient, cheaper to run and better performing. The downside is that such systems are highly sensitive and more susceptible to contamination and corrosion, brought about in most cases by poor water quality.
Cast iron boilers could withstand dirt, but their modern counterparts cannot – they will slow, malfunction or fail completely if dirt (magnetite) is allowed to populate a system. Magnetic dirt will only collect where air is present, so this must be constantly removed from a system by deaeration or degassing. If it isn’t removed, dirt will collect and breakdowns will be the result.
System imbalance
With the current emphasis on boiler quality and performance – geared around meeting stricter energy efficiency standards – water quality as an issue in itself is potentially at risk of being given scant consideration, which is to the detriment of long-term system health and functionality.
Poor system water quality will inevitably lead to system imbalance, which spells bad news for maintenance and management teams. Imbalance can lead to a risk of decreased pump performance, the possibility of increased breakdown periods, excessive wear on component parts and higher energy consumption as a result.
A poorly functioning system will result in a more expensive maintenance programme for management teams, and there is also the likelihood that system components will have to be replaced more frequently and the required energy efficiency standards will be harder to meet as a result. Boilers and component parts on new systems will be ‘A’ or ‘B’ energy rated from day one of installation, yet the level of energy efficiency achieved may rapidly decline if the water isn’t treated correctly.
For new installations, if the design is right for the building, and if the appropriate degassing unit has been specified for the size and type of building, then there’s an argument that no dirt separators should be required at all. Also, for that matter, there’s arguably no requirement to continually dose the system with inhibitors beyond the levels that are legally required, as heavy dosing can be more problematic in the long term.
Indeed, Spirotech installations at commercial sites such as the University of Strathclyde, the Motorpoint Arena Cardiff and the University of Wolverhampton have shown that the need for chemical dosing can be significantly reduced.
Chemical concerns
This issue is an important one to be aware of. While chemicals do have an important role to play when used correctly, overdosing of systems can have an adverse effect, especially when we consider that certain materials, like aluminium – when used for heat exchangers as part of a system – can actually speed up the corrosive process.
Maintaining good water quality should be an ongoing consideration, and this is especially true when carrying out annual servicing and maintenance. The introduction of any new liquid into the system must be properly treated and degassed, otherwise oxygen-rich liquids will give rise to the problems associated with air.
To ensure an air free system and a contaminant free circulating fluid, all water treatment programmes must include physical deaeration and dirt removal devices along with an appropriate dosing regime.
A good initial design, delivered in conjunction with a respected partner, will help guard against many additional factors that can also allow air to enter the system, such as an expansion vessel being too small or located at the wrong point, an incorrect initial fill pressure or pressure differences over regulating valves.
A key part of any good design, though, must recognise the importance of water quality as being at the root of a properly functioning system. If water quality is maintained, air and dirt will not populate and the resulting problems will not arise – resulting in a healthier and better performing heating system.
