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Installation, Operation and Maintenance Manual
MAN 564 Rev. 6
June 2020
Operation and Use
Section 3: Operation and Use
The system allows 'fail safe' operation when the pressure in the gas supply line drops
below a set value. The diagram shows the actuator in the 'fail safe' condition. When the
gas supply pressure drops below the pressure switch (5) set point, the pneumatic supply
to the solenoid valve (6) pilot is exhausted and the actuator moves to the 'fail safe' position
by using the gas stored in the tank (4).The tank is connected to the gas supply through the
check valve (3).
Pressurized air
Pressurized air (low pressure)
Atmospheric pressure air
Figure 19
ON-OFF service: air fail safe system
1
6
5
4
3
2
