10.14 Checking the safety relief valve activating pressure
In order to check the relief valve's activating pressure, the machine's working pressure is raised
above the activating pressure of the valve.
Switch the controller to the safety relief valve checking mode to carry out this check. This checking
mode is intended for machines with maximum permissible working pressure less than 215 psig.
Safety relief valves in machines with permissible working pressures higher than 215 psig must be
removed from the machine and tested on a special rig.
➤ Safety relief valves on machines with maximum permissible working pressure of 215 psig
should be tested only by an authorized KAESER service representative.
Blowoff protection and air system pressure monitoring are switched off during the test.
The machine must be isolated from the compressed air network and completely vented be‐
fore undertaking any work on the pressure system.
➤ Never operate the machine without correctly functioning safety relief valves.
Material Service fittings with accessories
(fixed to the machine)
Precondition The machine is switched off.
The machine is completely vented to atmospheric pressure,
i.e. both pressure gauges
2
and
9
(see Fig 23) are showing 0 psig.
➤ Note the safety relief valve activating pressure.
(the activating pressure is usually to be found at the end of the part identification)
10.14.1 Checking the compressor safety relief valve
Fig. 28 Compressor: Checking the safety relief valve
1
Air pipe
2
Union nut
3
Air pipe connection
4
Service fitting
5
Union nut
1. Undo the union nut
2
and remove the air pipe
1
.
2. Seal the connection for the air pipe
3
with service fitting
4
and union nut
5
.
3. Carry out an inspection as described in section 10.14.3.
4. Switch the machine off and depressurize completely.
Both pressure gauges
2
and
9
10 Maintenance
10.14 Checking the safety relief valve activating pressure
74
Operator Manual Screw Compressor
AIRTOWER 3C–7.5C Tri-Voltage
9_6917 34 USE
