What is the meaning of suction or discharge recirculation in centrifugal pumps?

Question

What is the meaning of suction or discharge recirculation in centrifugal pumps?

Answer 1

If you are using it in heating system it is calculated according the circulation discharge.This means one circle in the piping system,the water exits from the pump into the pipe when it comes back to the pump again this is one circle and when the water is circulating  starts to lose heat.In the system one type of pump pumps,the other type sucks.The first one is called discharge recirculation,the other is called suction.If the pipe line is too long you have to choose bigger circulation pumps because of friction of water in the piping system.Instead of that you use small suction pumps that helps for circulation.