freshwater system pump

[portlandtug25]

Has anyone else had problems with their R-25 potable water pump? Today when I turned it on it barely pumped, pausing 2-3 seconds between pumps. Normally it pumps at a high rate continuously when the tap is opened. This is my second pump in a year--the original failed completely last August and the factory replaced it. I've never run it dry.
Any ideas?

Thanks