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Energy effi ciency


Taking the heat out of system issues


Steve Simmonds, special projects engineer for water quality experts Spirotech, takes a look at the potential underlying problems of taking over a legacy system and what steps can be taken to mitigate any issues


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ometimes a heating system is destined to be troublesome, and it often comes down to the original specifi cation.


Not consulting with the experts at the outset


can be a costly mistake and what follows is an ongoing sticking plaster – metaphorically speaking - rolled out to provide a short-term solution. With the cost of energy, it is vital to run a system that operates optimally to minimise running costs and breakdowns. This means ensuring proper deaeration, dirt separation and pressurisation in major offi ce complexes and towering apartment blocks. From a technological standpoint, very little can be done to improve the effi ciency of modern boilers. So, in order to maximise energy effi ciency, end-users have to look at how system water can play its role in ensuring boiler effi ciencies are kept at optimum levels. By not considering the impact of the build-up of air and dirt on modern boilers, systems simply cannot run at full capacity or meet their effi ciency potential.


Incorrect design


An experienced facilities manager will identify and sort out some system issues quickly, but others will require further investigation, and this can often be traced back to mistakes made at the design or installation stage – or both. Specifying the right products for the right


applications is essential to the long-term health of new buildings or renovations. Key to this is the cooperation between specifi ers


and contractors; ensuring that what’s outlined in the planning stage is actually carried out at build


Left: Steve Simmonds, special projects engineer, Spirotech


means that there will be no water in the vessel because with equal pressures, the vessel will not be doing anything. The fi ll pressure should always be higher than the minimum pressure. Most people think they should be the same, but such an approach causes instabilities within the system and pressure fl uctuations.


Incorrect installation


stage, and that all parties involved in building and maintenance understand how to properly manage it to ensure optimum health and effi ciency. When it comes to designing an eff ective heating


system, getting it right requires specifying a mix of the right equipment to do the job, a thorough understanding of the technology and its application, as well as suffi cient knowledge and care during installation.


The need for education


There is an incorrect perception amongst some that the pressurisation unit controls what happens in the system and believe when they dial in a number, they have ‘set’ the pressure. But that’s not right. Pressurisation units are reactive, not proactive – responding to what’s happening in the system. How the system is designed is key to it working optimally. Preventing corrosion within a closed system is vital and, therefore it is imperative to remove the entrained air within it to achieve this. When it comes to taller buildings, failing to get the right pressurisation solution is likely to aff ect the system dynamics and suck air back into it, instead of taking it out!


Another area which


can be misunderstood is ‘fi ll pressure.’ An expansion vessel is only aff ecting the system when there’s water in it. Once you have correctly aligned your pre-set gas charge to the system requirements, you can then fi ll the system.


Most people fi ll the


system to the same pressure as they set the vessel to, but this


Substitution


Whilst recognising that budgets are often under pressure, the saying ‘buy cheap, buy twice’ certainly applies to heating systems. Cutting corners can prove expensive resulting in more maintenance ‘call-outs’ and accelerated replacement intervals. Even worse, is a contractor taking the arbitrary decision to not include one or more specifi ed components believing it won’t materially aff ect the running of the system…..that is clearly ridiculous. There is no doubt that whilst cost is an important


consideration, quality and performance should not be compromised. A higher initial cost can mean substantial savings in the long term.


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An imperfect installation doesn’t necessarily have a big impact on performance. One common fault is the wrong size of pipe used to connect the expansion vessel to the system. This will aff ect the fl ow to and from the unit, and possibly system pressure. It might not be the contractor’s fault; it could just be that there wasn’t enough detail in the drawing. Another potential mistake is installing the


pressurisation unit [pump] on the wrong side of the primary circulation pump (pressurisation unit). Incorrect positioning can result in the pump causing negative under-pressure, sucking in air at the top of the building through the air vents. It is not uncommon when the contractor is called in to sort out such problems as outlined above, that the product manual is missing. The manual can provide detail to override the system drawing and should be kept somewhere it can easily be found.


Poor maintenance regime


When a contractor is called-in to service a system having no access to historic data to refer to is far from ideal. It is good practice to keep updated maintenance records in an accessible place for when needed.


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