AERMEC Multichiller, Manual

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Sequential mode
Plant with variable flow on secondary circuit and independent pumps for every chiller, Set point chiller 5.0°C, COLD functioning.
Chiller 1 always On
Chiller 2 starts if SUW greater than 5.2°C
Chiller 3 starts if SUW greater than 5.2°C
Chiller 4 starts if SUW greater than 5.2°C
Chiller 5 starts if SUW greater than 5.2°C
Chiller 1 switches the compressors off on the basis of its own thermostat
Chiller 2 switched-off if SIW less than 7.8°C
Chiller 3 switched-off if SIW less than 8.8°C
Chiller 4 switched-off if SIW less than 9.3°C
Chiller 5 switched-off if SIW less than 9.6°C
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Load adjustment: TEMPERATURE
Probe position: the SUW probe (or probes) must be positioned on the
secondary circuit delivery, after the disconnecting device; the SIW
probe on the on the primary in the return input to the chillers after the
disconnecting device.
Plant features: management is optimised for plants where each chiller
controls its own pump (on/off together with the chiller) and with
secondaries with variable flow in the basis of the load
.
SUW
SIW
PRIMARY
SECONDARY Disconnect
This Adjustment directly controls the
delivery temperature to the secondary
circuit and it is possible to check up
to 3 branches of this circuit checking
up to 3 temperature probes SUW,
SUW2 and SUW3 (the latter only if the
pCOE expansion is used). The SUW,
SUW2,SUW3 delivery probes are consi-
dered for adjustment only if the relative
Flow meter contacts (respectively FL1,
FL2, FL3) are closed. In fact, the possi-
bility that every branch of the secondary
circuit is excluded due to stop of the
relative pump is also managed.
Conditions for switch-on of a new
chiller:
the switch-on of a new chiller is reque-
sted if one of the 3 delivery probes on
the secondary (SUW,SUW2 or SUW3)
reads a temperature greater than the
Leaving water temp. start chiller para-
meter (there is one for cold functioning
and one for hot functioning; the logic is
opposite for hot functioning)
SUW2 SUW3
Conditions for switch-off of a new
chiller:
the switch-on of the next chiller is
requested if the SIW probe reads a tem-
perature that is lower than the Return
water temp. stop chiller parameter. An
accurate calculation of the switch-off
temperature is requested, so that the
switch-off of a chiller sees to it that the
remaining chillers can guarantee a SUW
temperature that is less than the set
Leaving water temp. start chiller switch-
on set so as not to cause continuous
switch-on/switch-off of the chiller (there
is one for cold functioning and one for
hot functioning; the logic is opposite for
hot functioning)