The Salmson NSB 25-20 N was mostly used in some of the Hills Solar systems. We carry stock to replace these pumps in our vehicles.
One thing that is commonly missed resulting in over size pump replacement is the head rating on a pump is a static rating, and applies to the maximum head in an open loop system, such as pumping up to a roof tank. In the case of circulation through a roof panel and back down a return line, once the system is primed the weight of water falling down the return line is equal to the weight of water in the feed line. Essentially the pump only needs to overcome the total pipe friction in the system. When you take this into account the limitation is more to do with pipe length than the height.
Solar Hot Water Repairs QLD repair solar hot water systems on the Sunshine Coast . For all solar hot water inquiries please call 0455 265 539 or email email@example.com. Solar hot water plumbing.