Dunham-Bush WCFX 10, Инструкция по установке, эксплуатации и обслуживанию

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4
.
0 ELECTRICAL
4.4.6.18 Sensor Alarm
If the controller measures an analog
value (temperature, pressure.) that is far
beyond normal operating values, the
associated compressors are shutdown.
The controller then stores the alarm
code corresponding to the sensor alarm.
A sensor alarm indicates a problem in
the analog measurement system.
4.4.6.19 No-Stop Alarm
If the controller turns off a compressor,
but the compressor digital input does
not turn off, a No-Stop alarm is
generated. The controller will turn off
the control power relay which disables
all compressor control circuits and will
turn on the alarm light. This alarm
indicates a wiring or hardware error.
4.4.6.20 Low Differential Pressure
Alarm
For proper lubrication, a compressor
requires a 30 psig [2.1BAR] differential
pressure between condenser and
evaporator pressures. If the differential
pressure is less than 30 psig [2.1BAR]
for 3 minutes while a compressor is
operating, all compressors will be shut
down. The controller will store the low
differential pressure alarm code and
turn on the alarm light. The ‘Reset
Alarm’ key must be pressed to clear the
alarm.
4.5 CALIBRATION OF
SCREW COMPRESSOR
CAPACITY AMPS AT
FULL LOAD & MINIMUM
LOAD PERCENTAGE
1. Check calibration of all sensors (pressure
sensors, current transducers, temp sensors and
etc.). All calibration on sensors shall be done
in this step.
2. Load the compressor to full load. If the amps
reading do not match with calculated FLA
value within 2-3A, do this calculation: Amps
– FLA
For example, FLA = 150A, however the max
amps at full load is 130A, so, do the
calculation
130 – 150 = -20
3. Key in this value into “
Max Percent Cal
” of
the compressor in “
COMPRESSOR FLA
CALIBRATION
” mask under technician key.
4. Therefore, the value of FLA will change.
Verify that amps and FLA now match closely.
5. Manually unload the compressor all the way.
6. Locate the minimum percentage of capacity
for the compressor. If this value is 25% ± 3%,
no change required. Else, enter this value into
“
Min Percent Cal
” in the same mask. The
default value of “
Min Percent Cal
” is 25%.
For example, the minimum percentage of
capacity for the compressor is 32.2%,
therefore, enter 32.2 at “
Min Percent Cal
”.
7. Repeat this procedure for each compressor.
4.6 Master/Slave Control
Sequence
The optional master/slave control sequence is
used to sequence multiple chillers in one
installation according to the building load demand.
It also controls the dedicated chilled water pump
or motorized valve.
Vision2020i Controller offers this feature with
minimized field wiring cost compare to
conventional method that involves lots of
hardware cost. It is carried out this control
function via the advanced DBLAN
communication bus to implement the network
management for multiple chillers lead/lag
communication, sequencing and monitoring.
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