How do I select a check valve for my sump pump application?

There are 4 key factors to consider when selecting a sump pump check valve.

#1 – Desired Connection Type

There is a wide range of sump pump check valve models available, ranging from the economy BSC Series (Rubber Flapper Type 1-1/4”, 1-1/2” & 2” ABS sump pump check valves, which have various connection types including threaded, slip, flexible rubber couplers, barbs, to more robust flapper type 17-SPCV white PVC flapper type check valves such as our 17SPCV-1215 and 17SCC-15 & 17SCC-20 which have compression connections, 1-1/2” & 2” sizes are also available with Slip connections 17SCS & 17QSCS Series and True Union Slip connections 17SCTU & 17QSCTU Series.

#2 – Pressure / Temperature Rating Required

Depending on the required pressure and temperature rating required (see ratings above), these ratings may impact the model of valve you can select. For example, the BSC sump pump check valves are only rated to 25 PSI at 140°F (60°C) whereas the PVC valve are suitable for 150 PSI at 72° F (22°C). NOTE: End blocking of all compression connections is required to prevent linear pipe movement / blow-off.

#3 – Valve Size & Flow Velocity

Valve size is important, one must refer to the pump manufacturers installation instructions, typically the discharge piping must be equal to or larger that the discharge connection on the pump, a reduction in the discharge piping could potentially void the pumps warranty. The velocity at which the water is discharges through the valve and piping also needs to be taken into consideration. Velocity is often overlooked, under sizing will result in a flow velocity that is too high, a common cause of damage and failure of the piping and valve due to hydraulic shock / water hammer. On the other hand oversizing can result in build up of debris, water traveling too slowly cannot flush dirt from the valve components.

The chart below provided the minimum and maximum gallon per minute (GPM) for the piping size to maintain a desirable floe rate between 2 feet per second (fps) and 7 fps.



#4 – Gravity vs. Spring Assist (Quiet) Closing Design


GRAVITY CLOSING TYPE - One should consider that gravity closing type valves tend to be noisy due to the flapper slamming closed each time the flow reverses each time the pump stops. The Boshart gravity closing (rubber flapper type) check valves are designed with a 15°-degree valve seat which reduces the time and force at which the flapper contacts the valve seat, therefore they are “less noisy” than many sump pump check valves on the market.

Rubber flapper valves in which the gasket seal doubles as the flexible hinge for the flapper are best suited for smaller low HP pumps with low GPM ratings for example a pump discharging 21 GPM @ 2 ft/s asserts much less strain on the hinge than a high HP / capacity sump pump discharging 73 GPM at 7 ft/s velocity in which case the fluid asserts a great deal of force on a rubber flapper, for high capacity pumps the selection of a stainless hinge pin type valve is a better choice.


SPING ASSIST “QUIET” CLOSING TYPE - The Selection of a spring assist “Q” series QUIET Sump Pump check valve is highly recommended. They do cost a little more, however they are worth every penny. A silent swing check valve is manufactured with a S.S. mechanical hinge pin, this hinge system is much more robust and will have a longer life expectancy. The spring closes the flapper as the pump stops eliminating all flow reversal and water hammer, and therefore their closing is silent. The reduction in wear and tear on the valve and piping will extending the life expectancy of the system. You cannot go wrong selecting a valve with a mechanical hinge system they will preform well on all applications regardless of whether the pumps horsepower (HP) or capacity (GPM) is low or high.