A valve assembly of a fuel supply system includes a first body defining a first bore, an inlet port to receive fuel into the first bore, and an outlet port. The valve assembly further includes a pneumatic chamber disposed in fluid communication with the first bore. The valve assembly further includes a first piston to move between a first position and a second position. The first piston restricts and allows flow of fuel from the inlet port to the outlet port, in the first position and the second position, respectively. The valve assembly further includes a vent passage located upstream of the pneumatic chamber and configured to receive fuel leaked from a flow path defined between the inlet port and the outlet port. The valve assembly also includes a check valve disposed in the vent passage and configured to selectively vent the fuel entering the vent passage.