The hydro-pneumatic accumulator fitted on a cold water booster set in a roof top failed due to hydraulic shock caused by a lack of regular maintenance. The fact that the vessel failed was bad enough but the ensuing flooding of the top two floors caused £1000’s of damage. Routine regular maintenance would have avoided this situation.
Flow meter readings were obtained from a block of 166 apartments which measured a peak demand of 2.0 litres per second. National guides widely used in the industry calculated a duty flow requirement of 30.0 litres per second, over sizing the pump set by fifteen times! Subsequently over sizing the delivery pipe work system and electrical supply.
The energy consumption of the original 3 pump fixed speed booster set over a one week period was 924kWh. The pump set was replaced with a 5 pump variable speed booster set with each pump being much smaller than the original fixed speed pumps used. Power consumption over a week for the new pump set was reduced to 134kWh, a saving of 790kWh per week of wasted energy! This equates to a saving of over 18 tonnes of CO2 per annum, and saving £3,000 per year on the electricity bill.