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Refrigerant charge
Charge with unit stopped and in vacuum (refrigerant charge in the liquid phase)
Completely open the valve for it to close the service connection. Connect the refrigerant cylinder to the service connection without tight-
ening the connection. Half close the liquid shut off valve. If the circuit has been dehydrated and vacuum, load liquid with the cylinder
upside down. Weigh and charge the appropriate amount. Open the valve completely. Start the unit and let it run at full load for several
minutes. Check that the indicator is clear and without bubbles. Be sure that the transparency condition without bubbles is due to the
liquid and not to the vapor. For correct unit operation overheating must be at 4 to 7 ° C and subcooling at 4 - 8 ° C. Too high values of
overheating can be caused by a lack of refrigerant, while high values of subcooling may indicate excess charge.
After changing the charge, you should check that the unit works within the declared values: in full load operation, by measuring the
temperature of the intake pipe downstream of the bulb of the thermostatic valve; read the equilibrium pressure on the evaporator on the
low pressure gauge and the corresponding saturation temperature.
Overheating is equal to the difference between the measured temperatures. Measure then the temperature of the pipe of liquid leaving
the condenser and detect on the high-pressure gauge the equilibrium pressure on the condenser and the corresponding saturation
temperature. Subcooling is the difference between these temperatures. Charge is in the liquid phase.
Refrigerant charge addition with the unit running (refrigerant charge in the vapor phase)
CAUTION! Charge only vapor. Do not charge liquid because it may damage the compressor.
Connect the cylinder to the service connection without tightening the connection. Drain the connecting pipe and tighten the connection.
Charge each circuit until the indicator shows liquid without bubbles. The unit now has an adequate charge. Be careful not to overload
the circuit. Loading more than necessary leads to higher outlet pressure, higher power consumption and possible damage to the com-
pressor. Charge is in the vapor phase.
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