In a refrigeration seawater condensing system, keeping the condenser operating at a stable, safe pressure is crucial for efficient heat rejection and to protect components. A pressure reducing valve serves this role by dropping a higher incoming pressure to a controlled downstream pressure. This helps the condenser receive a steady pressure, even if seawater supply or pump conditions fluctuate, which keeps the refrigerant condensing process reliable and the system from overloading the compressor. Tubes are just passages for fluid, so they don’t regulate pressure. A seawater cooling pump provides the driving force for seawater flow but doesn’t regulate pressure itself. An expansion valve is part of the refrigerant circuit to control expansion into the evaporator, not to regulate pressure in the seawater condenser loop.