Issue: 01.05.2019
Page 10
Commissioning
Units with microchannel condenser coils
Care must be taken during charging a unit with refrigerant when a
microchannel condenser coil is fitted. Because the microchannel
coils hold less refrigerant than traditional fin/tube coils, it is easier
to overcharge, especially if the system is commissioned during
winter time when the ambient temperature is colder. If too much
refrigerant is added, this may cause tripping of the high pressure
switch in warmer weather. Always check that the amount of
condenser sub cooling is not excessive which may indicate
refrigerant overcharge.
System operation
Once the system is correctly charged with refrigerant and the
operating condition is stable, check that the compressor suction
superheat is between 10K and 20K and that the compressor
discharge temperature is between 50°C and 90°C. A suction
superheat that is too low may indicate liquid refrigerant return to
the compressor, whereas a suction superheat that is too high will
not provide enough cooling effect for the compressor and will also
cause high discharge temperatures. In either case, it is likely that
compressor damage/failure will occur.
For EVI Units Only:
Controller EXD-HP1
The controller EXD-HP1 used in the Series 4 EVI units operates as an
economizer control. The setting of controller is preset by the factory
and is password protected. Users are not allowed to change any
settings in the controller.
Safety Instructions:
Electrical Installation
•
Do not operate system before all cable connections are
completed.
•
Refer to wiring diagram for electrical connections.
•
Class II category transformer is required for 24VAC power
supply
•
Do not connect any EXD-HP1 input to main voltage as it will
permanently damage the controller.
•
When connecting wires of expansion valve and pressure
sensor, consider color coding as follow:
1.
EXM : BR: BROWN; BL: BLUE, OR: ORANGE; YE: YELLOW;
WH: WHITE
2.
PT5 : BN: BROWN; WH: WHITE
Display/ keypad unit (LEDs and button functions)
•
In standard
mode the superheat is shown at the display. In
case of liquid injection and economizer function this
changes to discharge temperature.
•
To display other data of EXD-HP1 press “SEL” button for 1
second until index number according to below table
appears. Release “SEL” button and the next variable data
will appears. By repeating the procedure variable data can
be displayed in sequence as measured superheat (K)
Measured suction pressure (bar) valve position (%)
Measured suction gas temperature (
°C) Calculated
saturated temperature (°C) Measured discharge temperature
(°C) REPEATING
Digital input Di1/Di2
•
The digital input Di1 is the interface between controller
EXD-HP1 and system controller if Modbus communication
has not been used.
•
The digital status is dependent to operation of system’s
compressor or demand.
Variable data
Controller EXD-HP1
Default Superheat, K
1 0
Suction pressure, bar
1 1
Valve position, %
1 2
Suction gas temperature, °C
1 3
Saturation temperature, °C
1 4
Discharge temperature, °C
1 5
Operating Condition
Digital input status
Compressor starts
Closed (Start)
Compressor stops
Open (Stop)
1. Read installation instruction carefully. Failure to
comply can result in device failure, system
damage or personal injury.
2. Only person having appropriate knowledge and
skill are allowed to manipulate the controller.
3. Disconnect all voltages from system before
installation.
