How does a check valve work on sump pump? 

What is a check valve? 

A check valve refers to a valve whose opening and closing part is disc-shaped, and rely on its own weight and medium pressure to prevent the backflow of the medium. It is one kind of automatic valve. The check valve can also be called: one-way valve, cut-off valve, return valve and back pressure valve. 

How does a check valve work on sump pump: 

1. the purpose of installing the check valve at the pump outlet is to only allow the pump to delivery the water to the outside, but not to allow the water to flow back to the pump in the reverse direction, so as to prevent the pump from reversing caused by high pressure returning water, when the pump stop running suddenly; 
2. A check valve is installed at the outlet of the water pump, so that when the pump stops working, the water in the pipeline of the micro-resistance slowing closing check valve will not flow back. There is also a check valve on the head of the suction pipe of the water pump, which can guarantee the water can be pumped up next time when the pump starts working. 

For more articles about check valves, kindly visit:

1. What are the 5 types of check valves?
2. How to inspect a check valve?
3. What is a lift check valve(lift disc check valve)?
4. What is wafer type check valve(also called butterfly type check valve)?
5. What is ball type check valve?
6. What is the difference between gate valve and check valve?