Additional Features For Customization - Emerson Copeland EazyCool ZX Series Application Manuallines

Automatic liquid injection on ZXMY: The electronic controller automatically instructs liquid
refrigerant to be injected into the suction line of the scroll compressor to reduce discharge
temperatures generated when the unit operates at increasing compression ratios. The electronic
controller reacts automatically to a thermistor which is attached to the discharge line on all ZXMY
units. The controller converts this signal for the linear stepper motor driving the liquid injection valve
to a position that enables the compressor to continue operating within its safe envelope.
Compressor phase reversal: Ensures that the compressor keeps running in one direction only
(clockwise = right rotation) – necessary for a compliant scroll compressor to compress and pump
refrigerant. Reset is automatic once the phase rotation is correct for the compressor.
Motor current overload protection: This feature eliminates the need for external current protection
for the compressor motor.
Fixed high-pressure switch: This is a non-adjustable protection device designed to prevent the
compressor from operating outside of its safe high-pressure range. Reset is automatic for a set
number of trips (7) then the unit will lock out and require manual restart. This feature is important to
prevent the ZX unit from cycling under these controls for a long period of time.
▪ ZXMY units:
31 bar cut-out / 22 bar cut-in.
▪ ZXDY units:
31 bar cut-out / 22 bar cut-in.
Adjustable high-pressure limitation: The unit controller provides the possibility to stop the unit at
a required discharge pressure which is lower than the cut-out value of the fixed high-pressure switch.
Detailed instructions can be found in chapter 2.10.5 "Additional features for customization"
hereunder.
Discharge temperature protection: Each unit is equipped with a discharge line sensor (NTC). The
information from the NTC sensor is used to activate liquid injection when required. The XCM25D
controller will stop the compressor if discharge temperatures reach unacceptable levels.
Adjustable low-pressure alarm: The unit controller features an adjustable low-pressure alarm
managed by the suction pressure sensor. The factory setting of this alarm is the lowest permitted
pressure of the refrigerant with the lowest pressure-vapour properties. If needed the user can modify
this value according to the required application.
▪ ZXMY units:
0.5 bar rel
▪ ZXDY units:
0.5 bar rel
A crankcase heater is directly connected to the controller. The crankcase heater will be energized
when the ambient sensor is below a given value (10 °C) and the compressor has been off for a
defined period of time (5 minutes). The minimum off time does not apply at initial power up.
In addition to the above, the ZX condensing unit has the following features:
▪ Liquid line assembly (filter drier and sight glass/moisture indicator)
▪ Anti-corrosion treatment to the condenser fins
The electronic controller is also the base controller for the connection of many optional and customer-
supplied functions such as:
▪ Main load controller (or thermostat)
▪ Evaporator electric defrost heater contactor
▪ Evaporator fan contactor
▪ Superheat controller for one electronic expansion device

2.10.5 Additional features for customization

A lot of additional features are provided by the XCM25D controller. In the European design of the
electrical panel a few of the additional functionalities are prearranged and can easily be installed by
connecting additional hardware to the electrical terminals. The tables in Appendix 6 show the
parameters that have to be changed in case a special feature of the controller should be activated.
The tables do not show the required settings which have to be done by the system operator, eg,
choosing correct setpoints for different components and different applications.
NOTE: After programming an additional function, the system will have to be restarted. To
engage system restart, switch off the main power supply, wait for 5 seconds and switch it on
again.
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