Reported hot water system failure


Some central hot water systems can fail after as little as 8 years of what seems normal service.

The hot water system below uses gas fired Rheem Ray Pak domestic hot water service heaters and Grundfos in-line circulating pumps configured into two blocks each with two heater units and two pumps, which, with associated storage tanks, serve a total of 164 unit.

The equipment was only 8 years old when the failure occurred.

Expert advice was that the velocity of the water being circulated by the in-line pumps was so high that cavitation in the water itself was eroding the copper bends and system pipe connections.

Pictures 1-4:The bright copper interiors of the eroded pipes. The eroded bend which revealed a similar leak in the pump suction bend was replaced and tested.

Picture 3: The paper-thin metal that that remained in the elbow, where a pinhole leak was revealed

Plant maintained by Simon Waugh of Canberra Boilers.

Alan Christie took the pictures – Contact him on 6282 0007 for more details.