Eliwell EWCM 4120, Manual, Page: 48 / 75

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Digital fans rotation
In the case of step fans, rotation of the fans can be controlled during activation and release by means of parameter
Fn11 . If Fn11=0 (fixed sequence), the activation sequence is fan 1, fan 2, ....fan n; The sequence is inverted during
deactivation, e.g. fan n..., fan 2, fan 1.
If Fn11=1 (operating hours), during activation the fan which worked the least is selected, while during deactivation
the fan which has worked the most is selected. The aim is to balance out the operating hours between all fans.
Maximum fans stop time
Parameter Fn18 indicates the maximum time for which the fans (continuous or digital) may remain off. Once this
time has elapsed, fan pick-up is forced for the time specified by Fn26 .
If, during the pick up time, the compressors are switched on, the minimum cut-off bypass will not be respected at the
end of the pick-up time, and in the absence of a request by the fan regulator the fans will immediately be switched
off.
If, during the pick up time, preventilation is activated due to the compressors being switched on, it will remain active
for any remaining time after the end of the pick up time.
The function is disabled if Fn18=0 or if Fn26=0.
The time the fans are off is reinitialised each time the device is switched on.
Fan operating hours
The operating time of the fans is stored every hour in EEPROM for the purpose of:

Managing the fan rotation function based on the operating duration.
 Enabling the signalling of an alarm if the fan operating hours exceed the maximum operating hours threshold.
Parameter Fn19 enables the maximum number of fan operating hours to be set.
The hours of use of each individual fan can be zeroed from the State menu.