Airedale OptiChill FreeCool 500kW - 1365kW - Manual (Page 51)

Chillers OPTICHILL
Chillers
51
Installation & Maintenance : 6564868 02/2013
Commissioning Data
OPERATIONAL SEQUENCE
Refrigerant Charge Liquid refrigerant should be charged into the condenser before compressor starting to
ensure that refrigerant is present at compressor start-up.
Compressor Oil Heater The mains supply to the compressor oil heater should be switched on at least 8 hours
prior to compressor starting to avoid refrigerant migration.
CAUTION A separately fused, locally isolated, permanent single phase and neutral supply
MUST BE FITTED for the compressor oil heater, evaporator trace heating and
control circuits, FAILURE to do so could INVALIDATE WARRANTY.
To reduce down time, if possible support the above supply with a UPS.
Pre-Start-Up Check Before compressor start-up, make sure that an oil level is showing in the compressor
sight glass, and that all refrigerant ball valves are opened, including the liquid
injection line.
Checks at Compressor
Start-up As soon as the compressor starts, make sure that the solenoid valve for liquid injection
opens, and that the suction and liquid/discharge pressure gauges are showing low and
high pressures respectively.
CAUTION If there is no liquid present or no differential pressure occurs, isolate immediately.
Check phase rotation by connecting pressure gauges to the suction and
discharge ports.
Capacity Control 4 Stage capacity control
CONTROL RELAY 1 2 3 4
START / STOP    
25% CAPACITY    
50% CAPACITY    
75% CAPACITY    
100% CAPACITY    
 Solenoid Valve De-energized
 Solenoid Valve Energized
 Solenoid Valve intermittent (10 sec on / off)
Adding Refrigerant Additional refrigerant should be added to the system via 1/4” Schrader connection on the
expansion line.
Pump Down Never shut the liquid injection solenoid valve during or before pump down.
Never pump down without the low pressure trip and high discharge temperature switches
being operative.
UNLOADING PROTECTION
Head Pressure The microprocessor has inbuilt protection against nuisance trips. If the head pressure
rises above 13.2barg the compressor will unload to 75% and remain unloaded until the
head pressure drops below 11.2barg.
Low Pressure If low pressure drops below the microprocessor setting, the compressor will unload to
75%, if low pressure persists for 1 minute, the circuit will be switched off and sound
an alarm.