These pumps are bidirectional. The standard pump motor unit is set up for normal rotation (clockwise when viewing the pump from the shaft end). Reversing the motor rotation will reverse the "in" and "out" ports and also requires changing the relief valve location. C990RX2B1 is equipped with an integrated relief valve setup for internal bypassing. The relief valve must always be located on the discharge side of the pump. This relief valve is not intended to be a metering or flow control device. Its purpose is to function as a discharge pressure relief to guard against intermittent downstream system restrictions. Overheating can occur within 5 to 10 minutes if the discharge line is completely shut off. The relief valve is located on the discharge side of the pump. The pressure relief setting is not set at the factory. To increase pressure, turn the relief valve adjusting screw in a clockwise direction.