C6.1.6/0613-0915/E 21
Pumpdown settings / Comments
2 = Thermostat temperature = TMT
Cut-out value for pumpdown, eg, 0.2 bar rel
1 = Suction pressure probe = SUP
2 = Case temperature probe = CST
4 = Thermostat temperature = TMT
Setpoint for temperature, eg, +2°C for meat
Positive differential defines upper cut-out
value
On time in case of probe failure
Off time in case of probe failure
7 = Liquid line solenoid = LLS
Table 22: Pumpdown 3
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.
The temperature value depends both on parameter G02 and parameter G11 (maximum
pumpdown time). It means that when the liquid line solenoid is off, the compressor will stop
because of suction pressure decrease within G11 time. If the running time of the compressor
exceeds G11 value, the compressor will be forced to shut down and the controller will generate a
pumpdown alarm.
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
set in a way that, in all operating conditions, it allows pumpdown to compressor cut-out value
C02 plus a defined safety time.
2.13 Reset to factory settings – Emerson "Hot Key"
2.13.1 How to save factory settings or user settings
There is no way to reset the XCM25D controller to factory settings other than with additional
equipment. Emerson Climate Technologies recommends to use the Emerson "Hot Key" to save
the factory settings at initial power up. The same hot key can also be used to save user settings.
By means of a special programming software (Emerson Wizmate) and corresponding hardware
(Emerson Prog-Tool), the user can:
preprogram hot keys
copy hot keys
change parameter levels
compare parameter lists
For further information please visit our website at www.emersonclimate.eu or contact your local
Application Engineering representative.
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