➤ Relief valves on machines with maximum permissible working pressure of 217 psig should
be tested only by KAESER Service.
Blow off 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 before
undertaking any work on the pressure system.
➤ Never operate the machine without correctly functioning pressure relief valves.
Preparation for the test
Precondition The machine is switched off.
1. Close the user's shut-off valve between the machine and the air distribution network.
2. Read off the activating pressure on the valve.
(the activating pressure is usually to be found at the end of the part identification)
3. Scroll to parameter 3 "Pressure relief valve check mode" with the arrow keys and confirm by
depressing the «enter» key for at least three seconds.
4. Enter the password "BASIC" and confirm with the «enter» key.
5. Use the arrow keys to select parameter "on" and confirm.
Carrying out the check
The machine starts in IDLE as soon as it is switched on.
As long as the «ON» key is depressed and held, the machine switches to LOAD and pressure builds
up in the oil separator tank. When the «ON» key is released, the machine switches back to IDLE and
switches automatically to STANDSTILLwhen the idling period has elapsed.
Precondition The machine is switched off.
WARNING
The pressure relief valve may blow off at any time!
Excessive noise is caused when the pressure relief valve blows off!
There is danger of scalding from hot oil.
There is danger of injury from bursting components and compressed air!
➤ Close all access doors and replace and secure all removable panels.
➤ Wear ear and eye protection.
➤ Abort the test if the working pressure rises 10% above the activating pressure of the valve.
1. Press the «ON» key.
The machine starts in IDLE.
2. Observe the display of pressure on SIGMA CONTROL BASIC while depressing and holding the
«ON» key.
3. Stop the test as soon as the pressure relief valve blows off or working pressure rises to 10%
above the activating pressure of the pressure relief valve.
4. If necessary, vent the machine and replace the defective pressure relief valve.
Returning the machine to operational
1. Call up the edit mode again and enter the password "BASIC".
2. Use the arrow keys to set the parameter to "off" and confirm with the enter key.
3. Open the user's shut-off valve between the machine and the air distribution network.
10 Maintenance
10.9 Pressure relief valve checking
Number: 9_6945 01USE
Service manual Screw compressor
Aircenter SX 3/7.5 SIGMA CONTROL BASIC
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