Hi, wondering anyone can help me make sense as to what is happening with my pump.

I have been using Grundfos Auto Pump CM3-5PC for over a year. But it started to act up last month. It won't shut off. I called the plumber who installed the pump to check for leaks and could not find any. Reset the pump, all back to normal until last week. Acted up again. Won't shut off. Husband reset, went back to normal. This week, it just won't shut off. Sometimes it works when I turn on and off the garden hose or kitchen tap. It would stop. But once it starts again, it won't stop. Sometimes, no matter what I do, it won't switch off.

FYI. I have a tank build outside for the pump, so it draws water from the tank. The tank takes from the main. There is a bypass which we can turn on, when the tank acted up. The water is pumped to the taps in the house, including up to the second floor where the pressure was weak before this. There are 2 tank upstairs that feed water to the bathroom. Bathrooms use normal heater pumps. So Grundfos only pumps water to the tanks upstairs.

I have called Grundfos to come and have a look. My feeling is that the sensor has malfunctioned. But I'm no expert. Am going thru water rationing at the mo, so I switch off the pump when water in the tank is low on the no-water days. Is the rationing affecting the pump? Or is this more of a plumbing problem? Grundfos is taking their time to send their tech guy, so wondering if it's worth calling a plumber whilst waiting.

Thanks in advance.

This post has been edited by puss.in.heels: Apr 2 2014, 01:30 PM