Annual. Check links and pins for wear or binding. Use a new pin to check holes in links for wear and use
a new link with the proper sized mating hole to check condition of pins. Replace as required. Check
bearings in linkage, on shafts, and in the control panel for any roughness and replace as required.
Lubricate bearings as required. Check gears for wear and proper meshing.
12. Restoring Cable and Position Transducers
Annual. Lubricate restoring cable sheaves and rod ends at servomotor connection. Check calibration of
Linear Variable Differential Transformers (LVDT's) or other position transducers.
Not Scheduled. Disassemble sheaves and inspect sheaves and cable. Replace sheaves if pulley is worn or if
bearings are rough.
13. Hydraulic System
Daily. Check level of oil in sump and actuator tank and add oil or charge pressure tank with air as required.
Weekly. Switch lead pump to lag and vice versa.
Monthly. Switch strainers and clean or replace filter element. If pumps are equipped with hour meters,
note run time. Compare run time to previous months readings and investigate any large deviation.
Annual. - Prior to scheduled maintenance, send sample of governor oil to laboratory for analysis. If
analysis shows filtration is required, drain and filter oil.
When oil is drained, clean oil sump and actuator tank with lint free rags and squeegee, inspect, and repaint
as required. Check condition of float valve disk, seat, float, and float arm for any damage or wear. Check
condition of float, cable, and sheaves of level switches for wear and free operation.
After system is refilled, check operation of pump unloader valve. Check operation of pressure relief valves
on pumps and actuator tank. Relief valves on the actuator tank should be set to operate at 10 percent
higher than the working pressure. The pump relief valves should be set to operate at a slightly lower
pressure than the actuator tank relief valve. This is to prevent the pumps from continuing to fill the
actuator tank should a high pressure condition in the system occur.
Check calibration and operation of pressure and level switches and reset as required. Check
annunciation where applicable.
With wicket gates blocked, time pumping cycle for each pump, noting the length of time the pump is on, the
rise of the oil level in the actuator tank, and the length of time between pumping cycles. Compare to
previous readings. If pump is taking longer to reach operating pressure or is pumping more frequently,
check for leaks in the system.