Printing fluid delivery devices

A printing system comprising:

• a printing fluid supply;
• a fluid delivery device comprising a pressure-controlled mode in which a pump in fluidic communication with the printing fluid supply is to operate at a pressure sufficient to open a pressure relief valve in fluidic communication with an outlet of the pump, the device including a recirculation valve movable between an open position in which a recirculation path from the outlet of the pump towards a second supply port is established and a closed position in which a feeding path from the outlet of the pump to a printhead port is established;
• and
• a controller to operate the recirculation valve based on an operating mode of the fluid delivery device,
• wherein in the pressure-controlled mode, the recirculation valve is in the closed position.

A printing method comprising operating a fluid delivery device in a pressure-controlled mode or a recirculation mode, the fluid delivery device comprising:

• a printing fluid pump,
• a return fluid path including a pressure relief valve to receive printing fluid from an outlet of the pump, the return fluid path fluidly connected to a region upstream the pump, and
• a recirculation valve movable between:
• an open position in which a recirculation path from an outlet of the pump towards a supply port is established, and
• a closed position in which a feeding path from the outlet of the pump towards a printhead port is established,
• wherein operating the fluid delivery in the pressure-controlled mode comprises setting the recirculation valve in the closed position and moving printing fluid along the feeding path and the return fluid path.