The old system was a gravity fed, vented hot water system. The hot water flow rate out of the taps was poor and to boost the flow to the showers, the client had a pump fitted. The pump was getting old and noisy. If you can, having an unvented cylinder installed will solve the poor flow rate issues and do away with the need for a noisy shower pump. We checked to flow rate and pressure of the cold main feeding this property, as we always do, as this is a good measure of how the new hot water system will perform. The customer was over the moon with their end results.