Compressor Motor Protection; System Pressure Protection; High-Pressure Safety Switch; High Pressure: Pressure Relief Valve - Emerson Copeland EazyCool OM 501 Series Application Manuallines

2.15 Compressor motor protection

The electronic controller protects the compressor motor against the following:

phase loss

incorrect phase rotation

voltage imbalance

2.16 System pressure protection

2.16.1 High-pressure safety switch

A non-adjustable high pressure switch is protecting the system against too high pressures.
The device will open in the event of an abnormally high discharge pressure (above 28.8 bar).

The unit will stop then and restart automatically after a 5-minute delay and after unit
pressure has decreased to 24 bar.

2.16.2 High pressure: pressure relief valve

There is a connection port sideways on the top of the unit liquid receiver for a pressure relief valve.
It is a thread with 3/8"-NPT connection. The pressure relief valve is not factory-assembled.

2.16.3 Low-pressure safety switch

In a way similar to the high-pressure sensor, the electronic controller registers the switching action
of the adjustable low-pressure switch, which will open in the event of an abnormally low suction
pressure:

The unit will stop then restart automatically after a 3-minute delay (D28) and when the unit
reaches the cut-in pressure level.
The unit is always equipped with a suction pressure transmitter which also takes care for protection
against vacuum operation. In rare instances of controller breakdown the low-pressure switch
would allow to run the unit in emergency mode (rescue mode).

2.17 Other inputs of the XCM25D controller

2.17.1 Customer-supplied control – Heat recovery / On/Off / Room Thermostat
The electronic controller is equipped with a digital input (DI3) open/close signal (such as the
switching action of a normal commercial thermostat) and relays a similar action as an output to
the compressor contactor in the case of a thermostat-controlled (parameter "C05") system (see
wiring diagrams in Appendices 2 and 3). If the system is controlled by low-pressure cut-out for a
multiple evaporator system and/or pump-down system, the controller XCM25D accepts signals
directly from an adjustable low-pressure switch (optional).

2.17.2 Ambient temperature sensor

An ambient temperature sensor supplied by Emerson is connected to the electronic controller.
This temperature sensor has several functionalities like emergency mode control, lower fan speed
limitation and crankcase heater control. The sensor is located at the housing on the backside of
the compressor compartment.
2.18 Output of the XCM25D controller – Alarm output (DO5)
The digital output DO5 is pre-configured as an alarm contact. The relay (max. 5A, 250V AC) is
activated in case of alarms and lockouts. Warnings will be shown only on the controller display.
By help of parameter S01 this setting can be adjusted.
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