Every now and again, a product is used in an application which isn’t fit for purpose and the consequence of doing so becomes evident very quickly. However, these situations can also be treated as lessons learnt and this brief article has been written to help understand the effects of high differential pressures across a flow control valve.
In this instance, unbeknownst to All Valve Industries, a Cimberio 746 series balancing valve was used to control the circulating flow of cold water through various circuits in a building, much like you would for a domestic hot water system, with the aim to reduce stagnant cold water and the risk of Legionella.
The issue was that rather than relying on a circulating pump with a relatively low head pressure for the circulation, the system used the mains water and booster pumps which were normally used to provide the peak flow demand to the building. This mains pressure water circulated through the system and back to an open tank for recirculation.
In order to provide the design flow for each circuit and balance the system, the Cimberio 746 series balancing valves were installed at the end of each circuit. Although the flow rates achieved were correct, the valves had to create a pressure loss of nearly 500kPa, whereby the maximum suggested pressure loss for these balancing valves is 50kPa.