Repairing or replacing HVAC plant on restricted metropolitan streets or other confined urban spaces can pose significant logistical challenges.

One way to help mitigate the disruption associated with this is to carry out retrofit or replacement operations at night when the area is not so busy, and the work will result in less disturbance.

This was the option chosen when LH-plc was employed by facilitates management giant Bouygues E&S to deliver a major turnkey chiller replacement project for North Middlesex University Hospital in Edmonton, London.

Chilled water is provided by two dual circuit packaged air-cooled water chillers, with remotely located associated pumps and strainers. The project included removal of the old chillers and installation of a pair of Daikin screw compressor chillers.

All the crane lifts, changeover operations and equipment commissioning were carried out at night to avoid any disruption to the hospital theatres.

Continuity of cooling

A key requirement on the project was to maintain continuity of cooling to the building throughout the entire installation. To this end, a pair of hire chillers – one 500kW and one 750kW – were installed on the runway immediately outside the chiller compound.

The project demanded experience of night working and rigorous attention to detail in order to ensure plant fitted into the tightly confined space, with sufficient room for service and maintenance operations.

Indeed, one of the features of this project was a pressing requirement for the HVAC design to take account of the need for ease of access for maintenance and repairs. This requirement applies whenever a HVAC system is replaced or renovated.

So, for example, it pays to make provision for maintenance personnel easily to approach air handling units, particularly if they are on the roof, so access walkways are essential for clear and safe admission to hard-to-get-at areas.

It is also important that HVAC system dampers are easy to reach so they must not be fitted behind walls or ceilings that have no access doors. Indeed, well-located access doors or panels – fire rated and/or insulated if necessary – make a positive difference to get at HVAC componentry that would otherwise be restricted.

Another common access problem is associated with air handlers being wedged into tight spaces so maintenance personnel cannot service the system coils and other components and care must be taken to ensure that the design mitigates this.

Ease of access will save in the long-run

Although the provision of easy access might involve some expense, this will pale into insignificance compared with the cost of failing to offer adequate maintenance. After all, a catastrophic breakdown has the capacity to close a business down completely, so paying attention to the need for adequate  access at the design stage is a worthwhile investment.

Isolation control valves installed behind equipment makes them difficult even to find let alone to fix, so ensure they are positioned in a way that makes them easy to get at. Access, however, is not the only consideration when it comes to making the work of service people simpler. It is, for example, also crucial to install a sufficient number of isolation valves. Without these, service staff might be obliged to shut down big sections (or even the entire) building.

Finally, remember that none of the access or other considerations will make any difference if you fail to provide good maintenance or the right design and installation in the first place. So, employ a company that you can trust with the depth of knowledge and experience required to offer a high-quality service.

Get more information about LH’s chiller maintenance services.