Tank to Pump

Pump Operations

Hydrant Changeover

Hydrant changeover is the transition from running on tank water to running on a hydrant supply without interrupting the attack line. Done smoothly, the line never notices the source has changed underneath it.

A pump schematic fed by a booster tank (blue) and a fire hydrant (gold). Toggling tank-to-pump, the hydrant intake, and the hydrant connection walks the supply through three states — tank-only, changing over (both sources open), and hydrant-only after the tank valve is closed — with an indicator for when it is safe to close tank-to-pump.

Tank-to-hydrant changeover · interactive

TANK ONLYThe line is running on the onboard booster tank — your starting point. The tank is finite, so set up the hydrant before it runs low.

Not yet safe to close tank-to-pump — the hydrant is not supplying the pump.

Changeover controls

The order is the lesson: open the hydrant intake and confirm it's connected first, then close tank-to-pump. Close the tank before the hydrant is feeding the pump and the line drops — try it and watch the tank path flash. This is a training aid; follow your SOPs.

Start from the booster tank, then crack open the hydrant intake. Once the hydrant is supplying the pump, you can safely close tank-to-pump to complete the changeover without losing pressure to the attack line.

The goal is continuity: bring the hydrant water to the intake, open it, and back the tank out so the line stays charged the whole time. As flow comes on, the operator watches the hydrant's static pressure become a residual reading under load.

Rushing the changeover risks losing the line or air-binding the pump. The skill is sequencing the valves so the pump always has a source — tank water covering the gap until the hydrant is carrying the load.

Where this shows up

See also