A pressure fryer comprising: a cooking chamber ; a valve that selectively vents the cooking chamber ; a filtration system including a filter pump that draws cooking medium out of a drain pan and through a filter assembly ; a pressure assist system that includes an air pump for selectively supplying a gas into the cooking chamber ; and a controller in communication with the valve and the pressure assist system , the controller being configured to: detect a closure of the valve ; determine a pressure in the cooking chamber ; compare the pressure in the cooking chamber to a predetermined pressure to determine whether the pressure in the cooking chamber is less than the predetermined pressure; in response to the pressure in the cooking chamber being less than the predetermined pressure and the valve being closed, applying power to the air pump to activate the pressure assist system to supply the gas into the cooking chamber to further pressurize the cooking chamber ; compare an amount of time the pressure assist system has been active to a maximum allowable time to determine if the amount of time exceeds the maximum allowable time; and in response to the amount of time exceeding the maximum allowable time, deactivate the pressure assist system . a cooking chamber ; a valve that selectively vents the cooking chamber ; a filtration system including a filter pump that draws cooking medium out of a drain pan and through a filter assembly ; a pressure assist system that includes an air pump for selectively supplying a gas into the cooking chamber ; and a controller in communication with the valve and the pressure assist system , the controller being configured to: detect a closure of the valve ; determine a pressure in the cooking chamber ; compare the pressure in the cooking chamber to a predetermined pressure to determine whether the pressure in the cooking chamber is less than the predetermined pressure; in response to the pressure in the cooking chamber being less than the predetermined pressure and the valve being closed, applying power to the air pump to activate the pressure assist system to supply the gas into the cooking chamber to further pressurize the cooking chamber ; compare an amount of time the pressure assist system has been active to a maximum allowable time to determine if the amount of time exceeds the maximum allowable time; and in response to the amount of time exceeding the maximum allowable time, deactivate the pressure assist system . detect a closure of the valve ; determine a pressure in the cooking chamber ; compare the pressure in the cooking chamber to a predetermined pressure to determine whether the pressure in the cooking chamber is less than the predetermined pressure; in response to the pressure in the cooking chamber being less than the predetermined pressure and the valve being closed, applying power to the air pump to activate the pressure assist system to supply the gas into the cooking chamber to further pressurize the cooking chamber ; compare an amount of time the pressure assist system has been active to a maximum allowable time to determine if the amount of time exceeds the maximum allowable time; and in response to the amount of time exceeding the maximum allowable time, deactivate the pressure assist system . <EOS>