Trane CGA Series, Установка, эксплуатация и обслуживание

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Refrigerant charge
Charge with unit stopped and in vacuum (refrigerant charge in the liquid phase)
Open the shut off valve as far as possible so that it closes the service coupling. Connect the refrigerant cylinder to the
service coupling without tightening the coupling. Half close the liquid shut off valve. If the circuit has been dehydrated
and is in vacuum, charge the liquid by turning the cylinder upside down. Weigh and charge the appropriate quantity.
Open the valve completely. Start up the unit and leave it running at full charge for some minutes. Check that the indicator
is clear with no bubbles. Make sure that the transparency condition without bubbles is due to the liquid and not to the
vapour. Correct functioning of the unit allows for overheating of 4 - 7° C and subcooling of 4 - 8°C. Values of overheating
which are too high may be caused by a lack of refrigerant, whereas high subcooling values may mean an excess of
charge.
After intervention on the charge, it is appropriate to check that the unit runs within the declared values: with unit steadily
running on a full charge, measure the temperature of the suction line downstream of the thermostatic valve bulb; read the
balance pressure to the evaporator on the low pressure manometer and the corresponding saturation temperature.
Overheating is equal to the difference between the temperatures measured in this way. Then measure the temperature
of the liquid line coming out of the condenser and read the balance pressure to the condenser on the high-pressure
manometer and the corresponding saturation temperature. The subcooling is the difference between these temperatures.
Charge in the liquid phase
Refrigerant charge addition with the unit running (refrigerant charge in the vapour phase)
WARNING! Charge vapour only. Do not charge liquid because it may damage the compressor.
Connect the refrigerant cylinder to the service valve without tightening the coupling. Drain the connection piping and
tighten the coupling. Charge each circuit until the indicator indicates liquid without bubbles. Now the unit has the required
charge. Make sure not to overcharge the circuit. Charging more than necessary leads to higher delivery pressure,
greater power consumption and possible damage to the compressor.