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User Guide | Optyma™ iCO2
1. Condensing unit control
1.1 Control
Following explanation refer to the overall control. Initial settings required at the test run are described on page 25, "5.1-Procedure and
caution for commissioning".
(1) Control items
This Condensing unit (CDU) has the following control functions.
Category
Control name
Start
Control at start
Ordinary
Calculation frequency control
operation
Fan control
control
Medium pressure control
Inching prevention control
Auxiliary control
Subcooling degree suppression
control
Protective
High pressure protective control
control
(1)
Overcurrent protective control
Discharge temperature overheat
prevention
Oil return control
Control valves
Electronic expansion valve for
middle pressure receiver inlet
Electronic expansion valve for
liquid bypass
Electronic expansion valve for
subcooling coil
At inverter error
Inverter error control
Demand control
Frequency changing speed change/
stop control
Note: Protective control initiates an extraordinary operation in order to protect the product when it is expected that it may run out the
allowable ranges for the refrigeration cycle devices and electro/electronic parts.
Once it reverts, as a result of control, to a state that it can operate within the allowable range, the control function is released and it returns to
ordinary operation.
(2) Explanation of control
States of operation on the condensing unit can be observed on the segment and LED on the "condensing unit control PCB". Method of
the segment display, display items, and control contents are as explained below.
(a) Display method
1. Each item is displayed on the 7-segment display of 3-digit x 2 on the condensing unit PCB.
2. To control the display, use SW7 to SW9 buttons.
SW9: Button to set the tens place of the code display.
SW8: Button to set the ones place of the code display.
SW7: Data delete/write button
3. Select the code No. of each item by pressing SW9 for the tens place or SW8 for the ones place.
There are following 2 types for the identifying alphabet at the code display section.
"C": "C00" to "C99"
"P": "P00" to "P99"
4. If SW9 (tens place) is pressed, it jumps to the leading code at each tens place. It passes over "C00" – "C99", and displays "P00".
5. SW8 (ones place) displays in the order of 0 → 1 → 2 ... 9 → 0. It displays in the order of "P00" → "P01" →"P02" ... " "P09" → "P00".
6. Adjust at the code to change, hold down SW7 (Data write/delete) for 3 seconds continuously.
7. Data at the data display section flickers at every 0.5 second. (Unless SW is pressed for 10 seconds in this state, the write mode terminates.)
8. Press SW9 (tens place) and SW8 (ones place) to change data.
9. If SW7 is pressed for 3 seconds or more continuously in the state of flicker, the date display section changes to the data lighting. By this
operation, data of each item is saved in E2PROM, and the operation is controlled with this content henceforth.
10. Contents which have been changed and saved are used for control even if the power supply is turned off and backed on again.
© Danfoss | Climate Solutions | 2023.01 | LCA012A030
Description
Bypasses the start step at the starting.
Changes the operation frequency of Condensing unit (CDU) based on the low pressure (LP).
Controls the gas cooler fan speed aiming to achieve the high pressure being determined by
ambient temperature.
Controls the aperture of medium pressure receiver inlet electronic expansion valve to make
constant the medium pressure being determined by ambient temperature and setting
evaporation temperature.
Operation immediately after a stop is inhibited to reduce the numbers of starts and stops.
Controls the aperture of subcooling electronic expansion valve, when it exceeds the upper
and lower limit values of subcooling degree.
Reduces the operation frequency when the high pressure (HP) is too higher.
Reduces the operation frequency when the current value is too higher.
It controls the liquid bypass electronic solenoid valve and reduces the operation frequency
further, when the discharge temperature (Td) is too higher.
Controls such that Condensing unit oil will return to the compressor.
Controls the aperture of electronic expansion valve to make constant the medium pressure.
Lowers the discharge temperature by controlling the aperture of electronic solenoid valve,
when the discharge temperature (Td) is too higher.
Controls the aperture of electronic expansion valve to maintain the subcooling coil
superheat degree constantly.
Control when the inverter PCB detects an error
Lowers the maximum speed of operation frequency.
BC408445719305en-000101 | 3
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