Are there any problems with replacing a 1/3 hp pump with a 1/2 hp pump?
A. When used in similar conditions, a 1/2 hp pump will pump more water and lift it higher than a 1/3 hp pump. Most new sump pumps will have a chart or graph in the instructions or on the box that shows the flow versus height of lift for both sizes. The flow is usually given in either gallons per minute or gallons per hour (multiply gpm by 60 to convert to gph). The height of lift is given in feet of vertical lift. There shouldn’t be any problem, but where the flow into the sump is relatively slow there would be no advantage to using the larger pump. However, in situations where water flow can become rapid, a 1/2 hp pump may be able to keep up with the flow where a 1/3 hp pump may not.
