2.1. The deactivation pressure of the pump-down pressure switch is higher than the deactivation
pressure of the LP pressure switch: in this case, the rising pressure will deactivate the LP
pressure switch before the pump-down pressure switch, therefore there is no risk of LP alarms
on re-start. If the deactivation of the pup-down pressure switch takes place within time PD04,
from the opening of the solenoid valve, the compressor/step is activated. If this is not the case,
there will be a pump down alarm on start-up.
2.2. The deactivation pressure of the pump-down pressure switch is lower than the deactivation
pressure of the LP pressure switch: in this case the rising pressure will deactivate the pump-
down pressure switch before the LP pressure switch. From the time of deactivation of the
pump-down pressure switch, if the rising pressure deactivates the LP pressure switch within
time AL01, the compressor/step will be activated. If this is not the case, a LP alarm will be
signalled, managed with standard methods.
3. AL02=2: the compressor/step remains active and the pressure continues to decrease until dropping
below the activation threshold of the pump-down pressure switch (supposing that this occurs within
time PD04). The compressor/step is switched-off only at this point. On the successive activation
request of a compressor in the circuit in question, the circuit solenoid valve is activated to favour the
re-equilibrium of the pressure inside the circuit. The compressor/step is not enabled on working while
the pump-down pressure switch remains active. If the deactivation of the pup-down pressure switch
takes place within time PD04, from the opening of the solenoid valve, the compressor/step is
activated. If this is not the case, there will be a pump down alarm on start-up.
44.6.4 Pump-down active in shut-down and in re-start, based on the analogue input relative to the
evaporation pressure.
The behaviour is the same as described in the 2 previous examples depending on the thresholds set at
parameters PD02 and PD03.
44.7 TIMED PUMP DOWN FUNCTION
Timed pump down can be managed by setting parameters PD05 and PD06.
WARNING:
The enabling of the timed pump down function disables all other types of working inherent to this function.
Par. PD05 Pump down time in start-up
0 = function disabled
! 0 function enabled for the set time
Par. PD06 Pump down time in stop
0 = function disabled
! 0 function enabled for the set time
44.8 PUMP DOWN ALARM IN START-UP AND STOPPING
It is possible to manage the reset and memorisation in the historical alarms of the pump down alarms in
start-up and stopping by means of the Pd family parameters.
Par. Pd07 Maximum number of pump down alarm interventions/hour in stopping
exceeding which the alarm is recorded and signalled with code on the display and the alarm relay+ buzzer
are activated
Reset is always manual if Pd07 = 0
Reset is always automatic if Pd07 = 16
Reset passes from automatic to manual if Pd07 goes from 1 to 15
Par. Pd08 Maximum number of pump down alarm interventions/hour in start-up
exceeding which the alarm becomes with manual reset, it is recorded and the alarm + buzzer are activated
Reset is always manual if Pd08 = 0
Reset is always automatic if Pd08 = 16
The reset passes from automatic to manual if Pd08 goes from 1 to 15 and on the basis of the configuration
of Par. Pd09
Par. Pd09 Enabling of pump down alarm in start-up automatic or manual reset if the number of hourly
interventions is reached Pd08
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