Do I need to replace the water pump ?

I have a pressurised MR Power Steam Elite (model 330016). When switched on, all seems OK but after a few minutes, the water fill button lights up even though the tank is full. Steam stops although the iron still heats up. Looks like the iron isn't getting water from the tank. Does anyone know where I can buy a new water pump for this particular model or is there one pump that will fit all MR pressurised steam generators ? Thanks in advance.