Safety Valve - Atlas Copco LT 2 Instruction Book

Instruction book
Reference
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4
Unload mechanism
The pilot valve is equipped with a hand-operated unload mechanism: by turning the red handle (1) 90 degrees,
the plunger of the valve will be lifted, releasing the spring force. The air pressure from the pulsation dampers
will force down unloader plunger (8) and the compressor will run unloaded. By turning handle (1) 90 degrees
further, the plunger returns to its original position so that the pilot valve will again unload and load the
compressor at the pre-set pressures.
Setting of the pilot valve
The maximum pressure is controlled by adjusting screw (2):
1. Loosen handle (1) and the two nuts (3)
2. Turn the adjusting screw (2) clockwise to increase the maximum pressure.
3. The pressure difference can be increased by removing one or more shims (4).
4. Fit the two nuts (3) and handle (1) in their original position.
6.7

Safety valve

Replace the valve if it does not open at the correct pressure. No adjustment is allowed.
Testing: Testing as described below shall only be carried out by competent personnel.
Testing
1. Close the air outlet valve, depressurize and disconnect the hose or pipe from the valve
2. Start the compressor and run it until it stops automatically.
3. Switch off the voltage.
Remove the cover from the air pressure switch and, with the air receiver now under pressure, turn the
adjusting screw one turn clockwise to increase the stopping pressure
switch and Adjustment of MRD3 pressure
4. Switch on the voltage, slightly open the outlet valve and start the compressor
5. Gradually close the outlet valve while checking the air pressure gauge. If the safety valve has not opened
at the pressure specified in
before the specified opening pressure is reached, repeat the procedure as mentioned from step 3.
6. Readjust the unloading pressure as described in sections
Adjustment of MRD3 pressure switch
7. Reconnect the hose or pipe to the closed air outlet valve
Testing on Trolley
1. Close the air outlet valves, depressurize and disconnect the hoses from the valves.
2. Loosen the red handle of the pilot valve (1) and the two nuts (3)
3. Open outlet valve (AV1) a fraction. Start the compressor.
2920 7089 90
Description
Unloading handle
Pressure adjusting screw
Nuts
Shims
Compressor
switch. Reinstall the cover.
data, it must be replaced by a new one. If the compressor unloads
Adjustment of MDR4S pressure switch
Adjustment of MDR4S pressure
and
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