Operation Between Power Failure And Power Recovery - Daikin EWWD440AAYNNO series Installation And Operation Manual

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.

Operation between power failure and power recovery

[A]
ON
Unit power
OFF
[A]
ON
Compressor
(magnetic switch)
ON
PLC
±30-100 msec
EWWD440~850AAYNNO**
Packaged water-cooled water chillers
4PW25558-1B
1
2
[B] [C]
[B] [C]
OFF
OFF
±500 msec
Table 4: Time from power failure to power recovery
ON-OFF limiting of the compressor (At
power recovery)
During on the unit ON-OFF
A normal
open contact
is used for
contact ON at
power
Automatic
recovery
start of
During
compressor
A normal
remote
after power
open contact
ON-OFF
recovery
is used for
contact OFF
at power
recovery
Pulse contact
is used
Table 4 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.
Compressor condition from power
failure to power recovery
[A] [B] [C]
Does not
perform
continuous Does not
operation Stops stop
No Yes Yes
— Yes No
— Yes Yes
— Yes No
— Yes No
Installation and operation manual
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