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USER MANUAL – Release 1.2 of 01/01/2010
Page 116 of 191
Version: 02/03/2010
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Exceeding (upwards) the threshold set in parameter PD02 added to the hysterisis set in parameter
PD03 by the pressure detected by the circuit LP transducer.
•
Exceeding the maximum duration of the pump-down cycle defined at parameter PD04. In this case, a
pump-down alarm will be signalled on start-up
depending on the parameter settings and the analogue and digital inputs.
44.1
PUMP-DOWN FUNCTION WITH CIRCUIT LOW PRESSURE PRESSURE SWITCH
Once the pump-down function has been activated, on shutdown the solenoid valve closes and waits for the
intervention of the circuit LP pressure switch or expiry of the maximum time before switching the compressor
off.
If configured (parameter PD01=2 or 4), when the pump-down function is activated on start-up, the solenoid
valve is opened and the compressor/step is not activated while the LP pressure switch remains active or the
maximum time has expired.
44.2
PUMP-DOWN FUNCTION WITH DEDICATED PRESSURE SWITCH
Once the pump-down function has been activated, on shutdown the solenoid valve closes and waits for the
intervention of the circuit pump-down pressure switch or expiry of the maximum time before switching the
compressor off.
If configured (parameter PD01=2 or 4), when the pump-down function is activated on start-up, the solenoid
valve is opened and the compressor/step is not activated while the pump-down pressure switch remains
active or the maximum time has expired.
44.3
PUMP-DOWN FUNCTION FROM ANALOGUE INPUT
Once the pump-down function is activated on shutdown, the solenoid valve closes and waits for the pressure
detected by the low pressure transducer to fall below the value set in parameter PD02.
If configured (parameter PD01=2 or 4) when the pump-down function is activated on start-up, the solenoid
valve is opened and the compressor/step is not activated while the pressure detected by the low pressure
transducer exceeds the value set at parameter PD02 addition of the hysteresis set at parameter PD03.
44.4
PUMP-DOWN FUNCTION IN COOLING MODE ONLY (Configuration possible
only for reversible units with the enabling of the working of the compressors in
heating mode).
The function is active in cooling mode only. In heating mode, the solenoid valve is piloted in parallel to the
compressors.
WARNING, IF SWITCH-OFF WITH PUMP-DOWN IS ENABLED, IF THE UNIT IS PUT IN STAND-BY
(COOLING / HEATING) OR IN OFF REMOTE WITH ID, BEFORE THE COMPRESSORS ARE SWITCHED
OFF BOTH THE PRESSURE SWITCH AND THE TRANSDUCER WILL PERFORM THE SWITCH-OFF
PROCEDURE WITH PUMP DOWN.
44.5
LOW PRESSURE ALARM DURING THE PUMP-DOWN
The AL02 parameter defines the working of the low pressure alarm with pump-down enabled
Par.
AL02
= 0 the low pressure alarm is active in normal working mode.
Par.
AL02
= 1 the low pressure alarm is inhibited during compressor stopping in pump down mode and with
compressor at a standstill. On compressor re-start, if the LP alarm is active, opening of the solenoid valve is
allowed only to favour the balance of the pressure but no compressor start-up is allowed until the LP
pressure switch is deactivated. If the pressure switch does not deactivate within time AL01 the LP alarm is
signalled.
Par.
AL02
= 2 the low pressure alarm is inhibited during compressor stopping in pump down mode and with
compressor at a standstill and at compressor re-start. Any LP alarm will be detected after the start-up of the
compressor once the AL01 by-pass has expired.
