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Checking the refrigerant level
•
After a few hours of operation, check whether the liquid level indicator has a green ring: a yellow color
indicates the presence of humidity in the circuit. In such a case the circuit must be dehumidified by
qualified personnel.
•
Large quantities of bubbles should not appear through the liquid level indicator. A constant passage of
numerous bubbles may indicate that the refrigerant level is low and needs to be topped up.
•
Make sure the overheating of the cooling fluid is limited to between 5 and 8 °C: to this end:
1 ) read the temperature indicated by a contact thermometer placed on the compressor intake
pipe;
2 ) read the temperature indicated on the scale of a pressure gauge likewise connected to the
intake side; refer to the pressure gauge scale for the refrigerant R410A.The degree of overheating
is given by the difference between the temperatures thus determined.
•
Make sure that the Sub-cooling of the cooling fluid is limited to between 3 and 5°C: to this end:
1 ) read the temperature indicated by a contact thermometer placed on the condenser outlet pipe;
2 ) read the temperature indicated on the scale of a pressure gauge connected to the liquid inlet at
the condenser outlet; refer to the pressure gauge scale for the refrigerant R410A, The degree of Sub-
cooling is given by the difference between the temperatures thus determined.
@DNOVA THN_R410A-IOM-1506-E
Warning: all THND/U units are charged with R410A. Any top-ups must be made
using the same type of refrigerant. This operation is to be considered extraordinary
maintenance work and must be performed by qualified personnel only.
Warning: the refrigerant R410A requires "POE" polyolester oil of the type and
viscosity indicated on the compressor rating plate. For no reason should oil of a
different type be introduced into the oil circuit.
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