Various embodiments of the present disclosure provide a random case sealer including a pneumatically-controlled top-head-actuating assembly configured to vary the speed of the top-head assembly when ascending (to make room for the case beneath the top-head assembly) and when descending onto the case (to engage the top surface of the case during sealing). The case sealer includes a pressure sensor that monitors the pressure of gas incoming from a gas source delivered to the top-head-actuating assembly via one or more valves. A controller controls the open level and/or the open time of the valves based on the pressure of the incoming gas to ensure the top-head-actuating assembly operates as desired regardless of whether the pressure of the incoming gas is equal to, below, or above a desired pressure. These features result in increased throughput compared to prior art random case sealers without requiring stronger cases or more protective dunnage.