An apparatus to detect fluid sealing of fuel tank includes a flow inlet and a flow outlet. The apparatus also includes a first flow path, fluidly connected between the flow inlet and the flow outlet, where the first flow path includes a fluid pump which pressurizes fluid from the flow inlet, the first flow path including an on-off valve to allow flow from the flow inlet to the flow outlet, the first flow path including a pressure sensor, and a flow control orifice located in the first flow path between the check valve and the flow outlet. The apparatus also includes a second flow path fluidly connected between the flow inlet and the flow outlet, the second flow path including an on/off valve located therein.