54
ENG
µchiller +0300053EN rel. 2.2 - 14.12.2021
Functions
Below is a diagram that represents operation for the confi guration with one pump only:
Thermoregulation
Enable Delay
Unit ON
Pump ON
Flow alarm
Flow alarm
delay from
pump start
Flow status check,
Pump status
possible
compressor
star up
AND
OK
OK
OK
Not OK
Not OK
Not OK
300053_014_R01
Fig. 5.e
Temperature control is enabled only after the fl ow alarm delay from pump on, so as to prevent the compressors from starting if
there is no fl uid fl ow.
Depending on the confi guration, up to two user pumps can be enabled. Chiller includes the following features:
• with two pumps, automatic rotation to ensure fl uid circulation and equalisation of operating hours. Rotation is performed:
– at the end of a period that can be set, in hours;
– when there is an overload alarm on the active pump.
• management of the pump overload alarm (if available, depending on the controller and confi guration). Fault signal and
immediate pump deactivation.
• Management of a fl ow switch that monitors fl uid circulation in the system.
• frost protection with unit off : the pump is started so as to activate fl uid circulation (when the unit is on, the function is di-
sabled).
• pump anti-blocking: if the pump is off for more than a week, it is activated for 3 seconds.
User Code Description Def Min Max UOM
S U049 User pump rotation time 12 0 999 h
5.2.1 Cyclical pump activation during standby
When the chiller serves a chilled water tank (for example, in winemaking applications), the pump does not need to keep
running, consequently energy can be saved by stopping the pump when the cooling demand is met. Control is only calculated
when the pump is on. A function can be activated to:
• switch the pump off after the compressors are stopped by the temperature controller;
• activate the pump periodically, in order to reactivate the compressors and satisfy demand from the units.
300053_200_R01
U048 U080 U079 U079U080
Off
On
Off
On
C
P
t
t
User Code Description Def Min Max UOM
S U078 Unit pump in standby:
enable On-Off cycles
001 -
S U079 Unit pump in standby: On time 3 1 15 min
S U080 Unit pump in standby: Off time 15 3 99 min
Fig. 5.f Tab. 5.e
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