Maintenance & servicing
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Maintenance in air management
Paul Dresser, commercial director, Mansfield Pollard, asks what are the obstacles to effective maintenance in air management applications and how do you overcome these?
Furthermore, something that should not be overlooked is regular maintenance – this is vital to maintaining efficiency. It has been shown that preventative rather than reactive maintenance can reduce energy consumption cost by 5%-40% depending on the system or equipment involved and improve equipment life and uptime. Likewise, the spaces being served by the HVAC equipment should be evaluated
regularly for changes in occupancy and use, as activities conducted in a space also contributes heavily to indoor air pollution.
Where maintenance can help
Filters – blocked filters reduce the quality and volume of supply air and increase energy consumption. Most systems have both pre-filters and fine filters. The pre- filters are cost effective to replace and are there to protect the whole system. A 3 or 6-month regime of changing these pre-filters (dependant on the environment they are operating in) would show a significant increase in the lifespan of the primary fine filters and the equipment as a whole. Mansfield Pollard visit many sites with AHUs and quite often the pre-filters have never been changed or can have collapsed leading to damage and blockage of other internal components.
Paul Dresser, commercial director at Mansfield Pollard M
ost people will spend some of their time either living or working in a built environment and the quality of the air they breathe is paramount in maintaining their health. An essential factor in providing adequate fresh air is that all air management applications are effectively maintained. Serious thought needs to be given to the ongoing cleaning and maintenance of
a system at the time of installation, as contaminated air ducts and ventilation systems can affect a business in a variety of costly ways. These can include high capital expenditure on replacing prematurely deteriorated systems and in decreased productivity, damaged interiors and in some cases low morale. In addition, if the ventilation system doesn’t comply with the regulations of the Health and Safety Commission, then there is the risk of potential prosecution. The level of appropriateness is clearly defined in the TR/19 Guide to Good Practice: Internal Cleanliness of Ventilation Systems published by the Building and Engineering Services Association (BESA). This states that all mechanical ventilation systems should be regularly and properly cleaned, tested and maintained to ensure that they are kept clean and free from anything which may contaminate the air.
Another essential factor in providing adequate fresh air efficiently is that the
HVAC systems must be fitted with effective filtration to prevent the many particles and contaminants in the outdoor air from making their way indoors. With reducing quality of outdoor air in certain areas, specifically those that are
built up, this can be a cause for concern. An effective filtration system can mitigate this risk significantly and improve the overall air quality on entry into the building.
The global introduction of ISO 16890 filter classification, based on particulate
classes, means that filtration specification can be aligned to the real condition of the desired application.
32 April 2018
Coils – A coil that becomes blocked restricts air flow and no longer delivers the heat load to the airstream as required. Simple fine combing and cleaning on a regular maintenance regime is most effective at keeping the coil running at optimum performance.
Fans – Fan bearings experience excessive wear when poorly greased. The drop off in performance is significant when bearings deteriorate. Although the use of direct drive plug fans are more predominant these days the belts and pulleys of centrifugal fans require regular tensioning and maintenance. If a belt is damaged or worn, then it should be replaced.
Controls - It only takes one part of the controls system to become dysfunctional for the whole operation of the equipment to become ineffective. As an example, a temperature sensor providing false readings would prevent the three-port valve from operating and the correct heat load would not be supplied into the occupied space.
Lastly, designing the system – quite often, we come across situations in AHU plantrooms where other services have been positioned to clash with the maintenance access to the air handling unit which then prevents maintenance from being effectively carried out. Maintenance should first and foremost be considered by the system designers and coordination between all trades is key to ensure a project is brought to a successful conclusion. Many of the clients that Mansfield Pollard works for can have outdated ventilation systems which require updating to meet regulatory requirements. They may also wish to take advantage of new more efficient technologies which, in turn, leads to a reduction in operating costs. By working with the client, we are able to provide innovative ventilation solutions, with a focus on energy efficiency whilst ensuring minimal operational disruption.
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