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13.1.2 Refrigerant replacement procedure with unit running (refrigerant charge in the vapour phase)
Caution: 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 the circuit until the indicator indicates liquid without bubbles. Now the unit has the required
charge. Make sure not to over charge the circuit. Charging more than necessary leads to a higher delivery pressure,
greater power consumption and possible damage to the compressor.
The symptoms of a low refrigerant charge are:
Low evaporation pressure.
High value of superheating.
Low value of subcooling.
In this case, add refrigerant R410A. The system is provided with a charging port between the expansion valve and the
evaporator. Charge refrigerant until conditions return to work normal. Remember to replace the cap closing the valve at the
end.
IMPORTANT!
If the unit has not been provided with integrated pump on board, do not turn off the external pump before 3 minutes have
elapsed after turning off the last compressor. The early shutdown of the pump causes a water flow alarm failure.
Liquid sight glass
HR port
LP port
HP gauge
LP gauge
Scale
Gauge manifold
Refrigerant charge in the vapour phase
Page 28
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