Challenge

Letchworth-based Complete Building Services (CBS) was commissioned by Enfield Homes, the social housing arms-length management organisation (ALMO) for Enfield Council, to address water pressure issues in four tower blocks in Enfield. Pressure boosting equipment was required to get the mains water reliably up to the top of the 13-storey buildings.

The existing equipment, based in the basement of one of the blocks, had become unreliable. CBS was asked to provide a solution that would provide reliability, cost-effectiveness and the minimum of disruption to the tenants in the nearly 400 apartments affected.

Solution

CBS contacted Wilo UK who recommended their Wilo Comfort – Vario COR-2 Helix VE speed controlled pressure booster set, supplied with a CAVSA anti-surge valve to address the potential issue of hydraulic shock in the mains water system. Controlling the flow of water into the system can prove difficult, as affecting the flow rate under normal working conditions must be avoided. Wilo multi-pump sets are fitted with a CFS (controlled fill system) which limits the starting sequence after a forced shut down reducing the rate at which the system is refilled.

Preventing a vacuum can be achieved by fitting CAVSA valves (combined air vent and surge arrestor) at the top of each riser which acts as a vacuum break by allowing air to enter the system. These valves also control the release of the air from the system when it starts to refill, therefore slowing down the rate at which the water enters the system.

The pump set selected for this project combines three pumps: one operates; one can assist if the call on water exceeds the capacity of that first pump; the third ‘sleeps’. All three pumps operate on a cycle, ensuring even wear across each one, with the added benefit that there is no stagnation of water addressing any legionella bacteria issues in the system.

Outcome

The water was off to the nearly 400 dwellings for less than two hours whilst the old system was decommissioned and removed and the new one installed and powered up. There were no complaints from the pre-warned tenants.

Pressure booster set keeps water flowing in tower blocks

Pressure boosting pump sets - projects from other companies

Pressure boosting pump sets - companies

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