Internal Pumpdown With Temperature Sensor (Case Temperature); Figure 16: Pumpdown Functionality With Temperature Sensor - Emerson Copeland EazyCool ZX Series Application Manuallines

2.15.4 Internal pumpdown with temperature sensor (case temperature)

It is also possible to carry out pumpdown 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 2.15.3 "Pumpdown with room thermostat (not available with ZXDY units)".
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
with positive differential value G03.

Figure 16: Pumpdown functionality with temperature sensor

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
A19 0 = Not used = nu
C01 4 bar rel
C02 2 bar rel
C05 1 = Suction pressure probe = SuP
G01 0 = Not used = nu
G02 +2 °C
G03 +1 °C
G04 -10 °C
G05 +15 °C
G06 2 minutes
G07 1 minute
G11 3 minutes
G56 0 = Not used = nu
S07 0 = Not used = nu
Table 25: Internal pumpdown with temperature sensor
If temperature ≥ G02 + G03, switch on liquid line solenoid.
If temperature ≤ G02, switch off liquid line solenoid and the compressor will continue to operate until
most of the refrigerant on the low side boils off and is pumped through the compressor into the
condenser and receiver. As the suction pressure falls below the low-pressure cut-out value (C02),
the compressor will cycle off.
AGL_Unit_ZX_A2L_E_Rev00
Pumpdown settings / Comments
2 = Thermostat temperature = tnt
Cut-in value for pumpdown
Cut-out value for pumpdown, eg, 0.2 bar rel
2 = Case temperature probe = CSt
4 = Thermostat temperature = tnt
Setpoint for temperature, eg, +2 °C for meat
Positive differential defines upper cut-out value
Lower setpoint limit
Upper setpoint limit
On time in case of probe failure
Off time in case of probe failure
Maximum pumpdown time
1 = Yes
7 = Liquid line solenoid = LLS
25