65
ACTUAL LINE VOLTAGE >= OVERVOLTAGE THRESHOLD
(Not applicable for Rockwell UM VFDs)
Guide vane 1 has not been calibrated successfully
Guide vane 2 has not been calibrated successfully
* : If prestart Check condition is true, then resulting state is as indicated in the state number column.
Table 15 – Prestart check / alert – alarm conditions
The compressor RUN STATUS parameter on the default screen line now reads PRESTART. If one test is not
successful, the start-up is delayed or aborted. If all the tests are successful, the chilled water pump relay
energizes, and the main screen line now reads STARTUP.
4.2 Lubrication control
For the 19DV system, refrigerant is used to lubricate and cool the compressor bearings. The refrigerant lubrication
system includes refrigerant pump, pressure transducers, control valves, filters, liquid level switch See Fig. 37 for
the lube assembly schematic.
When the chiller is powered on, the controller will maintain liquid level in condenser float chamber. If liquid level is
low, refrigerant will be pumped from cooler to condenser high side float chamber until the liquid level switch is ON.
Once the operator pushes the start button, the system will go into prestart check process.
When Refrigerant Pump request is on for pre-lube and the bearing pressure difference is OK for start, if cooler
temperature minus leaving condenser water temperature is less than 5.6°C, pump refrigerant from Cooler to
Condenser until compressor is ON. Else, if cooler temperature plus leaving condenser water is equal or larger
than 5.6°C, pump refrigerant from condenser to bearing and drain to condenser until compressor is ON.
During pre-lubrication, if the bearing pressure difference is less than 55.2 kPa for 8 seconds continuously, the
chiller will shut down. To proceed to start-up, the bearing pressure difference needs to exceed 82.7 kPa during the
pressure verification time. The compressor will run after the pre-lubrication process. Refrigerant from the high side
condenser float chamber will be pumped to bearings and will drain to cooler. When chiller shuts down, the
condenser control valve will be opened and the refrigerant evaporator control valve will open (3-way valve will
connect evaporator to pump suction).
This position allows refrigerant to be pumped from cooler to condenser high side float chamber. When the chiller is
OFF, always open cooler control valve. During running, if compressor
is ON and the bearing pressure difference is less 68.9 kPa for 10 seconds continuously, the chiller will shut
down.
To Next Page
Loading...
Need help?
General
