How to Prime a Water Truck Pump

Priming a water truck or water cart pump before use is vital to preventing breakdowns and down time, particularly in relation to centrifugal pumps.

Why is it necessary to prime a pump?

Water truck pumps are only capable of pumping liquid, not gasses or vapors. For this reason the pump needs to be filled with water before operation to prevent damage to the seals and impeller. (Self-priming pumps need to be partially filled.)

A properly primed pump looks like this:

When there is air in the pump it looks like this:

This air needs to be replaced with water for pump to operate.

 

Priming a self-priming pump

If there is still water in the tank remove the priming plug on the top of the pump. Open the valve to tank outlet on suction system to allow water to flow through from the tank. Ensure the water level is at least up to the top of the suction inlet before closing the hand-valve. If filling from a dam/river ensure suction hose is also filled with water. Once the pump is started the impeller will mix the air with the water until the air is expelled. The tank will then begin to fill.

If there is no water in the tank, close the valve at the tank outlet. Use a bucket or hose to fill the pump and suction system with water. Once the pump is started the impeller will mix  the air with the water until the air is expelled. The tank will then begin to fill.

 

Priming a non self-priming pump

If there is still water in the tank open a valve on the pressure side of the pump to allow water to flow through. Open the hand valve at tank outlet on suction system to allow water to flow through from the tank. Once the pump is full, replace the plug. The pump is now primed. If filling from a dam/river with pump, the suction hose should be connected when priming so as to fill the hose as well as the pump.

If there is no water in the tank, close the valve at the tank outlet. Use a bucket or hose to pour water into the top of the pump until pump and suction system are full. Once the pump is full, replace plug and start the pump. The tank will begin to fill.

2 February 2017

Images courtesy of pumpstoreusa.com