Two different types of valves were installed in the pilot plant. The valves in the oil circuit (HTF) were globe valves with pneumatic actuator, and those in the molten salts circuit were globe valves with electrical actuator. Both types of salts did show operation problems. The pneumatic valve did have important leakeages, difficult to detect, giving bad operation and evaluation of the plant. The electrical valves did insert voltage signal in the system, damaging other equipment. Moreover, the electrical valves did leak through their caps. All these leakage problems show that commercial plants need to pay a lot of attention to the material selection of the valves gaskets, especially for those in the salts circuit.