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INDUSTRIAL AND COMMERCIAL HEATING MAINTENANCE


A distortion to the water fl ow caused parts


of the system to display unusually high- pressure drops, a phenomenon that can eventually lead to the water fl ows through the system becoming unbalanced. A lack of hydraulic balance makes it diffi cult to keep heat emitters at the desired temperature without setting the pump to maximum – which in turn can lead to pump noise and excessive velocity in the main fl ow and return circuit, and wasteful losses resulting from having to operate at full capacity. The requirement to raise water temperature


in the central heating circuit has a signifi cant effect on boiler effi ciency, especially with modern condensing boilers. In all cases, these effects can be avoided by pre-commission cleaning and fl ushing, the application of water treatment and periodic system water checks and maintenance. A thorough system clean not only restores system effi ciency and effectiveness, but is critical in preparing interior surfaces for effective corrosion and scale inhibition. This approach brings about a secondary


benefi t in that it also contributes to the life expectancy of plant. It shouldn’t be forgotten that sludge can lead to both boiler and pump


failure, while scale will compromise the performance of heat exchangers. Similarly, state-of-the-art boilers incorporate multiple heat sensors on the heat exchanger and fl ow and return pipes to accurately monitor temperatures, as well as a vortex fl ow switch to ensure there is suffi cient fl ow of water through the heat exchanger. All these sensors work together through the electronics of the boiler management system to ensure the boiler not only delivers the correct temperature to the system, but also operates at the highest possible effi ciency whatever the heating load. This process can be compromised if any


of these sensors become coated in debris and dirt from the system, resulting in a fl uctuating temperature and a loss in effi ciency. In conclusion, modern boilers and renewable technologies can deliver substantial returns in both domestic and commercial systems, but if their full potential is to be realised, they must be operating on an ‘as new’ system, with water treated to render it fi t for purpose. CJ


JOHN BAILEY is commercial systems director at Vaillant.


Sludge taken from a central heating system


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February 2013 CIBSE Journal 59


A UK FIRST


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