How does a gas pump know when to shut off?



Thanks for signing up!

Watch for us in your inbox.

Daily News

( WHTM ) — Pumping gas is an act so routine, drivers can do it on autopilot, zoning out while the gallons add up. But have you ever stopped to wonder just how that pump works? Or why your tank doesn’t overflow while you’re daydreaming?

There are large gas tanks underneath all the service pumps at a gas station. Gas stations have two or three of these large tanks, which can hold several thousand gallons of gasoline.

In order for the gas to come up from these tanks into the actual pump, it has to defy gravity. To do this, according to , most gas stations use a pump to get the gas from the storage tanks into the dispenser

Woman gives birth at McDonald’s, and her baby girl is fittingly nicknamed

How does the dispenser know when to stop pumping gas? It starts when the customer removes the pump handle from the dispenser. This action activates a switch that starts the flow of gas.

As the gas level rises in the car’s gas tank, the distance between the dispenser nozzle and the fuel grows smaller. A small pipe called a venturi runs alongside the gas nozzle. When the end of the venturi pipe becomes submerged with the rising gas, it chokes off the air pressure that holds the nozzle handle open and shuts down the gas flow.

Video: Ohio ‘dine and dash’ incident nearly turns deadly for employee stuck on car

Sometimes, this shutdown can happen before the tank is full as the fast-flowing gas backs up on its way to the tank, causing the handle to spring back before the tank is full. Pausing for a few seconds will allow the gas to continue into the tank and the pump nozzle to start pouring gas again. If you try to keep pumping without pausing, you run the risk of causing the tank to overflow.

Calling all decorators: Miami Twp. holding annual holiday home contest

Knowing more about how gas pumps work won’t change the price, unfortunately. The national average was $3.56 per gallon Sunday.

Copyright 2022 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

For the latest news, weather, sports, and streaming video, head to

Comments / 0

Comments / 0