My hot water is a gravity system and the shower has always been a pathetic trickle. Some time ago a friend gave me a couple of secondhand shower pumps, the sort with a central motor and pumps each end for hot and cold. He also gave me some hoses for connecting to the supply and shower mixer plumbing. These only fitted the newer of the two pumps, so that is the one I used. This unit had no markings for what pipe goes where so I looked at the manufacturers website where I found circuit diagrams. These showed the end connections as inlets and the top connections as outlets. I assumed that it did not matter which end of the machine was hot and which cold but now I am not so sure. I mounted the pump under the bath and connected the left end to hot and the right end to cold, to match the way the pipes enter the shower mixer. The pump works fine for a couple of minutes then the motor seems to slow down for a few seconds then shuts off completely, leaving the shower output the same trickle as it was without the pump. I decided to try the older pump so today I bought adapters for the hoses, 3/4 inch down to 1/2 inch. I just looked at the older pump, a Quantum and it is labelled cold on the left, hot on the right. Do you think these pumps are the same both ends or can the hot only go to the
designated end?