How long can a water pump run dry before burning out?

[JuliannaFitz]

Generally, a water pump should not run dry for more than 3 minutes. Below is relevant information about dry running of water pumps: Hazards of dry running: For plastic pumps or plastic-lined pumps, the allowable dry running time is even shorter. Otherwise, it may cause dry friction at the pump seal, damaging the pump seal and bearings. The pump impeller may also deform due to excessive temperature, and in severe cases, the motor may burn out. Centrifugal pumps won't sustain damage from brief dry running. Reasons for burnout during dry running: Whether using mechanical seals or packing seals, a dry-running pump lacks liquid lubrication, leading to dry friction and rapid damage. The rotating components and pump body of a dry-running pump will overheat. Without liquid cooling, thermal expansion can cause tight clearances (like seal rings) to seize. In multistage centrifugal pumps, the balance disc lacks water lubrication and will quickly burn out and fail.