Safety Valves and Inward Relief Valves

Safety Valves and Inward Relief Valves

Valves should be cleaned and installed in a similar manner to discharge valves. Where facilities allow, bellows-type safety valves should be subjected to a leak test before installation in the manner described in the Aircraft or Component Manufacturer’s Maintenance Manuals.

In some installations, safety valves are provided with electrical and manual override controls, in such cases functioning checks on the controls must be made after installation (e.g. limit switches of electrical actuators which may need to be adjusted to cut off the power supply when the valve is at the fully open and fully closed positions). Manual controls should be correctly rigged and checked to ensure that the controls and valve move in phase and operate freely over their full range of travel.

NOTES:

(1)    Limit Switch adjustment is normally carried out when the component is workshop tested.

(2)    After carrying out override control system checks, the appropriate controls should be reset to their normal positions.

Some valves incorporate an electrically-operated position transmitter which signals the valve position to an indicator in the crew compartment; checks should therefore also be made to ensure that the indicated positions correspond.