EWWD440~850AAYNNO**
Packaged water-cooled water chillers
4PW25558-1B
Installation and operation manual
25
Operation between power failure and power recovery
Table 4: Time from power failure to power recovery
■
shows the standard specification.
■
Magnetic switch and PLC have a little individual time difference.
■
In case of "Does not stop" in the column of "Automatic start of
compressor after power recovery", you are requested to input
the operation command to the unit.
■
ON-OFF limiting time when the time from power failure to power
recovery is [B] depends on normal ON-OFF limiting flow.
■
ON-OFF limiting time when the time from power failure to power
recovery is [C] becomes the minimum ON-OFF value (180
seconds).
■
When input of pump interlock at power recovery stays OFF, the
unit may get an abnormal stop.
1
When cooling mode is selected, the setpoint in “SET TEMP. IN
NORMAL COOLING” is the target temperature for chilled water.
2
When thermal storage mode is selected, the setpoint in “SET
TEMP. IN HEAT STORAGE COOLING” is the target temperature
for chilled water.
NOTE
■
Mode change is not available while the unit is
operating (nor during thermo OFF operation).
■
It takes maximum 1 second from the time when
the unit accepts the operation mode to the time
when the mode is confirmed. Set the operation
signal and mode signal with a time difference.
NOTE
Touching any of the items will display a brief
explanation on the item.
1
2
[A]
[A]
[B]
[B]
[C]
[C]
ON
OFF
OFF
OFF
ON
ON
±
30-100 msec
±
500 msec
Unit power
Compressor
(magnetic switch)
PLC
Compressor condition from power
failure to power recovery
[A]
[B]
[C]
Does not
perform
continuous
operation
Stops
Does not
stop
ON-OFF limiting of the compressor (At
power recovery)
No
Yes
Yes
Automatic
start of
compressor
after power
recovery
During on the unit ON-OFF
—
Yes
No
During
remote
ON-OFF
A normal
open contact
is used for
contact ON at
power
recovery
—
Yes
Yes
A normal
open contact
is used for
contact OFF
at power
recovery
—
Yes
No
Pulse contact
is used
—
Yes
No