Table 21: Pumpdown 2; Figure 11: Pumpdown Functionality With Temperature Sensor - Emerson Copeland EazyCool ZX Series Application Manuallines

Room thermostat switch status Liquid line solenoid valve status
Close Switch on / Energized
Open Switch off / De-energized

Table 21: Pumpdown 2

For example, if the room thermostat switch is closed, the liquid line solenoid valve is activated,
and the compressor will run when the suction pressure value is higher than the compressor cut-
in value C01.
The liquid line solenoid valve will be switched off if the room thermostat switch is open, then
pumpdown will start. The compressor will stop once the suction pressure value is lower than the
compressor cut-out value C02 or when the pumpdown time duration is longer than the maximum
pumpdown time G11 setting.
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 pumpdown time. G11 should be
adjusted in a way that, in all operating conditions, it allows pumpdown to compressor cut-out
value C02 plus a certain safety time, eg, 2 minutes).
2.12.3 Pumpdown with temperature sensor
It is also possible to use a temperature sensor for pumpdown functionality (not part of the
standard delivery). Parameters G56 and S07 have to be set up as described in Chapter 2.12.2
"Pumpdown with room thermostat".

Figure 11: Pumpdown 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).
20 C6.1.6/0613-0915/E