I recently installed a 2 bowl sink in my basement below the level of the main house drain. I found a 1/3 HP sink pump from Home Depot that I bought and installed. Supposedly the pump can pump water a maximum height of 15 ft.
I have attached photos of my set up: both basins drain into top of pump, pump discharges water horizontally about 1 ft though ball valve to regulate flow, makes 90 degree turn vertical and goes through rubber sump pump check valve while converting from 1.25 pipe to 1.5, flows vertically approximately 3 feet where it joins the existing laundry drainage and flows to the main drain.
The problem is that the pump continues to cycle on and off even after the water is turned off. It removes the water just fine and turns off but then a few seconds to a few minutes later it turns on again randomly and continues to cycle for no apparent reason.
Any idea why this pump can’t fully clear the water from the pipe and how to fix it?