C6.1.6/0117-1017/E
25
The functionality of parameter
G11
protects the cooled goods in case of component damage, eg, the
liquid line solenoid is mechanically blocked and not able to stop refrigerant mass flow. In that case
the compressor cut-out pressure will not be reached and the compressor will continue to run. The
only limitation to stop the compressor is the maximum pump-down time.
G11
should be adjusted in
a way that, at all operating conditions, it allows pump-down to compressor cut-out value
C02
plus a
defined safety time, eg, 2 minutes.
2.14.4 Internal pump-down with temperature sensor (case temperature)
It is also possible to carry out pump-down functionality in case a temperature sensor is used for
temperature control (not part of the standard delivery). Parameters
G56
and
S07
have to be set up
as described in Chapter 2.14.3 "Pump-down with room thermostat".
Figure 14: Pump-down functionality with temperature sensor
The control of a cold room or cooling cabinet can be realized with a temperature sensor (change
parameter
G01
according to the probe location). Parameter
A19
must be set up as thermostat
temperature. The temperature setpoint is defined by parameter
G02
. Adjust the temperature range
by means of positive differential value
G03
.
If the temperature increases and reaches setpoint plus differential, the liquid line solenoid output
relay will energize the coil to open the valve. The compressor will be controlled by suction pressure.
The temperature value is to be set between two parameters (
G04
and
G05
).
In case of fault in the thermostat probe the opening and the closing of the solenoid valve relay are
timed through limp along parameters (
G06
and
G07
).
Parameter Factory settings
Pump-down settings / Comments
A19
0 = Not used =
nu
2 = Thermostat temperature =
tnt
C01
4 bar rel
Cut-in value for pump-down
C02
2 bar rel
Cut-out value for pump-down, eg, 0.2 bar rel
C05
1 = Suction pressure probe =
SuP
2 = Case temperature probe =
CSt
G01
0 = Not used =
nu
4 = Thermostat temperature =
tnt
G02
+2°C
Setpoint for temperature, eg, +2°C for meat
G03
+1°C
Positive differential defines upper cut-out
value
G04
-10°C
Lower setpoint limit
G05
+15°C
Upper setpoint limit
G06
2 minutes
On time in case of probe failure
G07
1 minute
Off time in case of probe failure
G11
3 minutes
Maximum pump-down time
G56
0 = Not used =
nu
1 = Yes
S07
0 = Not used =
nu
7 = Liquid line solenoid =
LLS
Table 24: Internal pump-down with temperature sensor
S
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Inst
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Ma
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Dismant
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