Why we close discharge valve of centrifugal pump before starting?

>The discharge valve of the pump has to be closed during startup. This is maintained so, inorder to prevent sudden load on the power system, if the valve is open. If you look at the characteristics of the pump, the power required ,increases with flow rate.

What are the precautions to be taken while starting and closing a centrifugal pump?

Do not operate the centrifugal pump below the minimum rated flows or with the suction or discharge valves closed. These conditions can quickly lead to centrifugal pump failure and physical injury. Always disconnect and lock out power to the driver before you perform any installation or maintenance tasks.

What is the effect when a shut off valve is closed downstream of a centrifugal circulator?

A dead-head is caused when a centrifugal pump operates with no flow through the pump due to a closed discharge valve or blockage in the line. The pump is forced to circulate the pumped medium, causing the temperature to continually rise. As the fluid churns inside the pump it heats into a vapor.

Can you running a centrifugal pump with discharge valve closed?

If the discharge valve is closed and there is no other flow path available to the pump, the impeller will churn the same volume of water as it rotates in the pump casing. If the pump is run in this condition for a significant amount of time, it will become damaged.

What should be the status of the suction and discharge valves when starting a centrifugal pump?

Every centrifugal pump must be primed, vented and full of liquid before it is started. The pump you are about to start must be properly vented and primed. The suction valve must be fully open.

What happens if discharge valve of centrifugal pump is closed?

If the discharge valve is closed and there is no other flow path available to the pump, the impeller will churn the same volume of water as it rotates in the pump casing. The vapor can interrupt the cooling flow to the pump’s packing and bearings, causing excessive wear and heat.

Can a centrifugal pump running with discharge valve closed?

When first starting a centrifugal pump delivery valve is kept?

The delivery valve connects the pump outlet and the delivery pipe. It remains closed before the pump is switched on. When the pump builds up its pressure, it is opened and can be used to control or vary the discharge.