Engineering manual - SAB 193-233-283 S A-frame (including ATEX)
008831 en 2020.10
133/168
Maintenance instructions
11.3 Stopping routine
Comprehensive maintenance often requires the compressor to be stopped for a certain period of
time.
Stopping and starting up compressor during a short period of standstill
Before stopping the compressor, capacity must be reduced to the lowest capacity stage for a few
minutes.
During short periods of standstill, it is not necessary to shut off the suction stop valve and the dis-
charge stop valve. The heating rod must be energised.
If the compressor is cooled with cooling water, the water flow must always be stopped during
standstill periods. This is normally done by means of a solenoid valve in the water inlet line to the
compressor.
Connect the solenoid valve to the start/stop relay of the compressor motor.
Always start up the compressor at the lowest capacity stage. After start-up, capacity should be in-
creased stepwise at suitable intervals to avoid that a sudden excessive pressure reduction in the
evaporation system causes liquid hammering in the compressor and oil foaming in the crankcase.
Shutting down for a long standstill period (2-3 months or more)
If the plant is stopped for a long period of time, follow this procedure:
1. Close the main shut-off valve after the receiver.
2. Pump down evaporators. It might be necessary to adjust low pressure cut-out to a lower
suction pressure during pump down. Continue pump down until the suction pressure has
been reduced to a little above atmospheric pressure.
3. Close the suction and discharge stop valves and the stop valve in the oil return line.
4. Follow the plant instructions which indicate how to stop and close down the plant
correctly.
5. Shut off main and control power supply.
6. Remember to write down all actions in the log book.
11.4 Long-term storage
Long-term storage (6 months to 5 years) provisions are required, regardless of the storage envi-
ronment, if start-up and/or useful operation does not take place within six (6) months of equip-
ment shipment. Special provisions may be required for storage of less than six (6) months if the
storage area is subject to unusual environments such as high humidity, large temperature
changes or dusty atmosphere.
Long-term storage of equipment may lead to the deterioration of components over the period of
time. Synthetic components in the compressor may deteriorate over time even if they are kept
flooded with oil. A warm and dry environment is essential to minimise environmental and corro-
sive damage.
For further information, please contact your local sales representative.
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