CSV Back Pressure and Pipe Rating

On the inlet side of the Cycle Stop Valve the pressure will increase to make the pump think it is in a deeper well when less water is being used. Increased back pressure is good for the pump/motor as it will reduce the amp draw and make the motor run cooler.

However, we must make sure the pipe and fittings prior to the CSV, and the CSV itself are rated for as much pressure as the pump can build.

Normal submersible pumps can build less than 150 PSI pressure, and most pipe is rated for more pressure than that. Deep set submersible pumps maybe able to build more pressure than the pipe can handle. Deep set submersible pumps with a high static water level maybe able to build more back pressure than the CSV itself can handle.

To figure total back pressure we need to know the model of the pump. Looking at a pump curve at zero flow will give you the max pressure the pump can build. Some pump specifications will just list the max pressure the pump can build. All the pipe and fittings prior to the CSV must be rated for as much or more than the max pressure of the pump.

All pipe and fittings after the CSV will only see the pressure set by the pressure switch, like 40 to 60 PSI max. Each CSV has a max pressure rating and/or a maximum differential pressure. To figure the max pressure on the CSV subtract the static water level in the well from the max pressure the pump can build. If the pump can build a max head of 400’ (173 PSI) and the static water level in the well is 100’ deep, subtract the 100’ from the 400’ the pump can build for a max pressure on the CSV of 300’ which is the same as 130 PSI.

The CSV125 has a max pressure rating of 150 PSI. The CSV1A has a max pressure rating of 400 PSI and a max differential pressure of 150 PSI. The CSV3B series has a max pressure rating of 225 PSI and a max differential pressure of 125 PSI. The CSV3R series with a high-pressure regulator can have as much as 700 PSI max with a 200 PSI max differential. Differential pressure is figured by subtracting the set pressure of the CSV from the max pressure the pump can build. IE: If the pump gives the CSV a max pressure of 200 PSI and the set pressure of the CSV is 50 PSI there will be 150 PSI differential pressure across the CSV.