Take off the discharge pipe at the next connection after the pump and close it off. Switch on the pump and it should run then stop indicating that the pump has come up to cut-out pressure. If it does, then there is a leak somewhere along the line, but you would have noticed that by now. If it does not stop there is an internal leak in the pump valves. Open up the pump and carefully clean the rubber valves of scale deposits. This applies to the suction and delivery valves. I did this and it worked immediately. Apply some light Vasaline or similar to the rubber surfaces, it will soon wash away after a little use.
iengine, July 2008
