Method of operating a hydraulic system from an off-state in a cold environment

A method of operating a hydraulic system of a plant to resume operation from a minimum operating temperature of the plant, the hydraulic system comprising a plurality of hydraulic cylinder arrangements and a plurality of electronically operated valves, the method comprising

• controlling the valves in a first stage to cycle fluid from a tank through a bypass valve and directly back to the tank until the temperature of the fluid in the tank has reached a first interim level;
• and
• a second stage comprising
• controlling the valves in a first step to cycle fluid from the tank through the pressure lines of two or more hydraulic cylinder arrangements of the hydraulic system and back to the tank until the temperature of the fluid has reached a second interim level, and
• controlling the valves in a second step to cycle fluid from the tank through the pressure lines of a single hydraulic cylinder arrangement of the hydraulic system and back to the tank until the temperature of the fluid has reached a desired operating level.