Instructions
24 | AN405821998738en-000102 - 118A5495A
© Danfoss | Climate Solutions | 2023.02 | LCA012A024
9 – Setting the electronic controller
Following explanation refer to the overall control. Initial settings required at the test run are described on Page 35, 10.1 Checking before turning on the
power supply".
9.1 Control items
This condensing unit has the following control functions.
Category
Control name
Description
Start
Control at start
Bypasses the start step at the starting.
Ordinary
operation control
Calculation frequency control
Changes the operation frequency of condensing unit based on the low pressure (LP).
Fan control
Controls the gas cooler fan speed aiming to achieve the high pressure being
determined by ambient temperature.
Medium pressure control
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.
Inching prevention control
Operation immediately after a stop is inhibited to reduce the numbers of starts and
stops.
Auxiliary control
Subcooling degree suppression control
Controls the aperture of subcooling electronic expansion valve, when it exceeds the
upper and lower limit values of subcooling degree.
Protective control
(*)
High pressure protective control
Reduces the operation frequency when the high pressure (HP) is too higher.
Overcurrent protective control
Reduces the operation frequency when the current value is too higher.
Discharge temperature overheat prevention
It controls the liquid bypass electronic solenoid valve and reduces the operation
frequency further, when the discharge temperature (Td) is too higher.
Oil return control
Controls such that condensing unit oil will return to the compressor.
Control valves
Electronic expansion valve for middle pressure
receiver inlet
Controls the aperture of electronic expansion valve to make constant the medium
pressure.
Electronic expansion valve for liquid bypass
Lowers the discharge temperature by controlling the aperture of electronic solenoid
valve, when the discharge temperature (Td) is too higher.
Electronic expansion valve for subcooling coil
Controls the aperture of electronic expansion valve to maintain the supercool coil
overheat degree constantly.
At inverter error
Inverter error control
Control when the inverter PCB detects an error
Demand control
Frequency changing speed change/stop
control
Lowers the maximum speed of operation frequency.
(*) 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.
