76
ENG
µchiller +0300053EN rel. 2.2 - 14.12.2021
Functions
Waiting after cycle reversal (case with comp. ON) (8)
After reversing the cycle, there is a waiting time to ensure the correct fl ow of refrigerant; in this phase too, the ExV remains in
the 100% open position.
User Code Description Def Min Max UOM
S S045 Operation time at min capacity after cycle reversing 30 0 999 s
Dripping (case with comp. OFF) (9)
In this phase, the compressors, the electronic expansion valve and the fans are stopped, waiting for the coil to complete defro-
sting due to thermal inertia and stop dripping. The duration of the dripping phase can be set.
User Code Description Def Min Max UOM
S S048 Dripping: duration - 0=Dripping not performed 90 0 999 s
Post-dripping phase (case with comp. OFF) (10)
During this phase, the fans are started at 100% speed to completely expel any water still on the coil. The duration of the post-
dripping phase can be set. At the end of the post- dripping phase, the circuit is reactivated in normal heat pump operation.
User Code Description Def Min Max UOM
S S049 Post-dripping: duration - 0=Post-dripping not performed 30 0 999 s
Quick start phase (case with comp. OFF) (11)
The compressor restarts based on the control request and the unit returns to normal operation. The start- up time is reduced so
as to quickly bring compressor speed in line with the request.
User Code Description Def Min Max UOM
S S056 BLDC smart start: duration (*) 20 0 999 s
(*) Shortened compressor start-up after defrost
This action assumes that the compressor has been off for a very short time, and therefore does not require complete preheating
as is the case during normal start-up.
During the defrost phase (when the unit is in chiller mode), the fans are started if the condensing pressure exceeds the high
condensing pressure alarm threshold - 5K.
User Code Description Def Min Max UOM
M C017 Max high pressure threshold (HP) 65.0 0.0 999.9 °C
5.17.2 Defrost with fans
When the outside temperature allows (outside temperature > 6- 7°C), the fans alone can be used to defrost the coil, without
operating the compressors, so as to improve system energy effi ciency. When the outside temperature is greater than or equal
to the value of S069, the function is activated: in this condition, the waiting time S041 before the defrost request is halved (to
facilitate defrosting with fans only).
Note: if parameter S069 is set to 0.0°C (32°F), the function is disabled.
User Code Description Def Min Max UOM
S S069 Defrost with fans: outside temperature threshold
0.0=Function disabled
0.0 0.0 99.9 °C
The defrost phases are as follows.
300053_202_R01
EE
t (s)
Fan
CP
4WV
Defrost
1 5 9
102
Fig. 5.ad
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