FISCHER [CF] EASY User Manual page 68

applicable in case pumpdown is realized by means of an additional low pressure switch.
Operation of the unit below the suction pressures shown in the table could result in tripping of
the compressor internal motor protector (Klixon, error code E28). The envelopes are in
accordance with Select software.
Unit family R134a
CFME -20°C = 0.3 bar rel
CFLE [-]
CFDE
* For CFME020 it is limited to -20°C (1.35 bar rel)
Table 15: Minimum cut-out value for pumpdown
NOTE: The values in Table 15 show the lowest suction temperatures / pressures in the
envelopes. Depending on the condensing temperature in the real system it might be
required to adjust / increase the cut-out value according to the approved envelope
published in Select.
2.12.1 Pumpdown with room thermostat
Configure parameter C05 "Compressor regulation probe selection" to 3 (Suction pressure switch
/ Room thermostat input). In addition change setting for G56 from "0" to "1". This is information
for the controller that a solenoid valve exists.
Change the functionality of Digital Input 3 (DI3) (Parameter R07) to setting 1 (Suction pressure
switch / Room thermostat input) and adjust the relais output configuration S07 to 7 (Liquid line
solenoid).
Parameter Factory settings
C05 1 = Suction pressure probe
G56 0 = No
R07 0 = Not used
S07 0 = Not used
G11 3 minutes
C02 2 bar relative
Table 16: Pumpdown 1
Room thermostat switch status
Close
Open
Table 17: Pumpdown 2
For example, if the room thermostat switch is closed, the liquid line solenoid valve will be
switched on, 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).
2.12.2 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 2.12.1
"Pumpdown with room thermostat".
C6.1.6/0513-0515/E
R404A/R507
-20°C = 2 bar rel -23°C* = 1.1 bar rel
-40°C = 0.3 bar rel -40°C = 0 bar rel
Not approved for pumpdown
Pumpdown settings
3 = Suction pressure switch / Room thermostat
1 = Yes
1 = Suction pressure switch / Room thermostat
7 =Liquid line solenoid
Maximum pumpdown time
Cut-out value for pumpdown, eg, 0.2 bar (rel.)
Liquid line solenoid valve status
Switch on
Switch off
R407A R407F
-25°C = 1 bar rel
-40°C = 0 bar rel
15