GIW notes that “if you’ve ever seen the aftermath of a pump explosion, you know that such an event can be extremely destructive, costly, and even deadly. Preventing overheating of a centrifugal pump is crucial not just for pump operation, but also for safety at a very basic level. The essential problem is simple: If a suction or discharge valve is closed or blocked, the pump runs without any fluid. Under these conditions, as much as 40% of motor power is transferred to the fluid in the pump as heat. The pump temperature rises very quickly as the fluid turns to steam that can’t escape. In as little as 20-40 minutes, a pump can reach a high enough temperature to explode violently.
“To prevent pumps from overheating, it’s critical that you never run a pump with either the discharge or suction valve (or both) shut.
“What happens, though, if the valve is shut or blocked by mistake and you do experience a sharp temperature rise?
“DO NOT simply open the valve! The release of the built-up steam will be violent and can trigger an explosion. Instead, shut the pump down and wait until it has cooled completely before opening the shut or blocked valve.”