Refrigerant Charge - CIAT DYNACIAT power LG Serie Manual De Instrucciones

- Select the operating mode using the
water operation)
- Enter the setpoints for:
Chilled water
Hot water
- Start the unit by pressing the on/off button
- The internal safety devices are now activated. If one of these
safety devices is triggered, trace the fault, reset the safety
device if necessary and press the RESET button on the
console to clear the fault.
- The unit can only be started after 2 minutes (time required to
scan and enable all the safety devices). The control stages
should operate in cascade mode based on the demand.
Use either of the following to turn off the unit in non-
emergency situations:
- The On/Off button on the console
- A dry contact on the automatic operation control.
Do not use the master switch as the electrical cabinet
must remain powered on (antifreeze protection, crankcase
heater).
NOTE:
DYNACIAT machines use R410A. It is essential that
power
technicians use equipment which is compatible with R410A
with an operating pressure which is approximately 1.5 times
higher than that of units using R407C.
17.2 Essential points that must be checked
Compressors:
Ensure that each compressor is rotating in the correct
direction, by checking that the discharge temperature rises
quickly, the HP increases and the LP drops. If it is rotating in
the wrong direction, the electric power supply is incorrectly
wired (reversed phases). To ensure rotation in the correct
direction, swap two power supply phases.
- Check the compressor discharge temperature using a
contact sensor.
- Check the input current; it should be normal.
- Check all safety devices to make sure they operate correctly.
Hydraulics:
As the exact total drop in system pressure is not known at
commissioning, adjust the flow of water with the control valve
until the desired nominal rate is obtained. By causing the
pressure in the water system to drop, this control valve aligns
the system pressure/flow curve with that of the pump so that the
nominal flow rate corresponding to the desired operating point
is obtained.
The pressure drop in the plate exchanger (read using the
pressure gauge placed on the exchanger inlet and outlet) is
the reference to be used to check and adjust the nominal flow
rate of the system.
Follow the procedure described below:
- Open the control valve completely.
- Let the pump run for 2 hours to flush out any solid particles
in the circuit.
- Read the pressure drop in the plate exchanger when the
pump is switched on and then 2 hours afterwards:
• If the pressure drop has decreased, this means that the
screen filter is clogged. It must be removed and cleaned
• Repeat until the filter is completely clean.
- Once the circuit has been flushed of all contaminants, read
the pressure drop in the plate exchanger and compare it to the
theoretical pressure drop selected.
If the reading is higher than the theoretical value, the flow rate
button (chilled or hot
is too high. In other words, the pump is delivering too much
flow for the system load drop. Close the control valve one
complete turn and read the load drop. Continue by gradually
closing the valve until the nominal flow rate for the desired
operating point is obtained.
However, if the system pressure drops far below the available
static pressure delivered by the pump, the resulting water flow
rate will be low and the difference in temperature between the
exchanger inlet and outlet will be higher. This is why pressure
drops must be minimised.

Refrigerant charge:

The LG and LGP units are shipped with an exact charge of
refrigerant. To make sure that the unit is filled with the correct
charge of refrigerant, perform the following checks circuit by
circuit with the system running at full capacity:
- Check the overheating value which must be between 6 and
9°C depending on the type of unit.
- Check the actual subcooling value at the condenser outlet. It
must be between 5 and 8°C, depending on the type of unit.
- Check there are no bubbles in the liquid sight glass.
If the charge is too low, large bubbles will appear in the liquid
sight glass, the suction pressure will drop and overheating on the
compressor inlets will be high. Locate the leak, completely drain
the refrigerant charge using a recovery machine, and fill the unit
with a new charge. Repair the leak, pressure test the unit (do not
exceed the maximum service pressure on the low-pressure end)
then refill the unit. The refrigerant must be liquid and charged via
the liquid charging valve. The amounts of refrigerant indicated on
the data plate must be added to each circuit in the unit. Repeat
these steps if the subcooling temperature is below the specified
values.
NOTE:
An excessively low suction pressure or an excessively
high condensation pressure may sometimes be read when
commissioning the unit. These problems may have numerous
causes. Refer to the "Troubleshooting operating problems"
section for more information.
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To guarantee operation of the unit, it is essential to:
- adjust the regulator's safety parameters for the operating
temperature.
- Adapt the settings of the thermostatic expansion valve to
have overheating at + 7 °C.
- adjust the refrigerant charge, checking that the subcooling
values are between 5 and 8°C.
EN - 16
Operation with negative temperatures