GEA Grasso - Page 6

OPERATING INSTRUCTIONS
CO
2
/NH
3
CASCADE UNIT
250 - 1000 KW
6 _551511_om_kas_gbr_1_.doc
3.1.1 Use ...............................................................................................................................34
3.1.2 Design ..........................................................................................................................34
3.2 Refrigerant circuit ....................................................................................................................35
3.2.1 CO
2
low temperature stage.........................................................................................35
3.2.2 NH
3
high temperature stage .......................................................................................36
3.3 Oil return system......................................................................................................................36
3.3.1 CO
2
circuit oil return system ........................................................................................36
3.3.2 NH
3
circuit oil return system........................................................................................36
3.4 Auxiliary refrigeration unit for CO
2
separator ........................................................................36
3.5 Safety devices...........................................................................................................................37
3.5.1 CO
2
circuit ....................................................................................................................37
3.5.2 NH
3
circuit ....................................................................................................................38
3.6 Monitoring devices ..................................................................................................................38
3.6.1 CO
2
circuit ....................................................................................................................39
3.6.2 NH
3
circuit ....................................................................................................................39
4 Maintenance Instruction.......................................................................................................................40
4.1 General Information ................................................................................................................40
4.2 Servicing/maintenance and safety ..........................................................................................41
4.3 Searching for leaks on refrigerant side / leak test .................................................................41
4.4 Vacuating, charging and draining refrigerant and oil............................................................42
4.4.1 Evacuating the refrigerant (see also initial start-up) ..................................................42
4.4.2 Charging with refrigerant (see also initial startup; initial charge with refrigerant)..42
4.4.3 Charging characteristics...............................................................................................43
4.4.4 Draining the refrigerant ..............................................................................................43
4.4.4.1 General notes on draining refrigerant.........................................................43
4.4.4.2 Charging refrigerant.....................................................................................43
4.4.4.3 Connections for draining refrigerant...........................................................44
4.4.5 Venting the refrigerant circuits...................................................................................44
4.5 Charging and draining oil (see also putting into service).......................................................44
4.5.1 General notes on handling refrigerator oil.................................................................44
4.5.2 Check oil level ..............................................................................................................44
4.5.3 Oil filling.......................................................................................................................44
4.5.4 Draining, changing, checking oil .................................................................................44
4.5.5 Used oil ........................................................................................................................45
4.6 Maintenance Work..................................................................................................................45
4.6.1 General notes...............................................................................................................45
4.6.2 Opening the compressor (see also compressor maintenance instructions)...............45
4.6.3 Dismantling the compressor suction filter (see the compressor maintenance
instructions) .............................................................................................................................46
4.6.4 Replacing the suction filter..........................................................................................46
4.6.5 Changing the suction filter before refrigerant pump - CO
2
circuit.............................46
4.6.6 Oil change....................................................................................................................46
4.6.6.1 Meaning........................................................................................................46
4.6.6.2 Maintenance Work.......................................................................................47
4.6.6.3 Changing the oil ...........................................................................................47
4.6.7 Replace oil filter ...........................................................................................................47
4.6.8 Changing the filter driers - CO
2
circuit ........................................................................48
4.6.9 Clutch maintenance.....................................................................................................48
4.6.10 Oil pump maintenance (for external oil pump)......................................................48
4.6.11 Checking the pull-in torques at fastener of fixing base ...........................................48
4.6.12 Changing the oil fine separation cartridges .............................................................48
4.6.13 Finding and fixing leaks.............................................................................................49
4.6.14 Cleaning the heat exchangers (heat-carrier / cooling agent sides) .........................49