INNOV@ ECFAN DHR -AGU-0912-E • 19 •
7.3 Checks during operations
Check the phase sequence relay (only DX versions) on the control board to verify whether the phases occur in
the correct sequence: if they do not, disconnect the unit from power supply and invert two phases of the incoming
three-pole cable.Never attempt to modify internal electrical connections: any undue modifications will immediately
invalidate the warranty.
7.4 Checking the refrigerant charge (DX versions)
· After a few hours of operation, check whether the liquid level indicator has a green ring: a yellow colour
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 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.
· 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.
Warning: TREF units are design for R410A refrigerant.
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.
Warning: The air cooled (split) unit are Factory pre-charge with Nitrogen
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