Carrier 30RA Electrical connections and refrigerant charge, Liquid refrigerant charge, Example

30RA/30RH

Electrical connections and refrigerant charge

E N G L I S H

Electrical connections

WARNING:

To prevent electrical shock or equipment damage, make sure disconnects are open before electrical connections are made. If this action is not taken, personal injury may occur.

Power supply cable size and external connection must be made by the installer according to the unit installation characteristics and the applicable standards. The power supply and earthing multicore cable of the unit must be connected to the main disconnecting switch by passing it through the grommet on the front pedestal after removing the lateral access panel. The maximum section allowable for flexible copper cable is 25 mm2.

Before connection, check that phase sequence L1 – L2 – L3 is correct.

Take special care when making the earth connection.

The maximum permitted voltage and current imbalance is 10% of the values indicated in Table II.

Contact your local power company for correction of an incorrect line voltage.

Before selecting the power supply line fuses - which must be of the type "gG" - check the voltage and the size indicated on the unit name plate is.

WARNING:

Operation of the unit on improper line voltage constitutes abuse and is not covered by the Carrier warranty.

IMPORTANT:

To ensure the correct unit power supply (cable entry, conductor cross section, protection devices etc.), consult the electrical data table, the wiring diagram supplied with the unit and the applicable standards concerning the installation of air conditioning equipment.

Never operate a unit if the voltage imbalance exceeds 2%.

The following formula must be used to determine the percentage of voltage imbalance.

Voltage imbalance (%) =

Largest deviation from average voltage x 100

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Average voltage

Example:

Nominal supply: 400-3-50

AB =	404 V
BC =	399 V	Motor
AC =	394 V

Average voltage = 404 + 399 + 394 = 399 ≈ 400 V 3

Determine maximum deviation from average voltage

AB = 404 - 400 = 4

BC = 400 - 399 = 1

AC = 400 - 394 = 6

Largest deviation is 6 volts. Percentage voltage imbalance is therefore:

6x 100 = 1,5 %

400

CAUTION:

The installer must install protection devices, as required by the applicable legislation.

Liquid refrigerant charge

Checking the charge

WARNING:

When adjusting the refrigerant charge always ensure that water is circulating in the heat exchanger to prevent any possibility of freezing up. Damage caused by freezing is not covered by the product warranty.

30RA-RH units are shipped with a full operating charge of refrigerant. Refer to Table I.

If it is nevertheless necessary to add more refrigerant, run the unit for some time in cooling mode and then slowly add liquid refrigerant into the suction side until there are no bubbles in the sight glass.

WARNING:

To ensure proper operation of 30RA-RH units there must be at least 5 K of subcooling as the liquid refrigerant enters the expansion valve.

30RA-RH units use a HFC-407C refrigerant charge. For your information, we are reproducing here some extracts from the official publication dealing with the design, installation, operation and maintenance of air conditioning and refrigeration systems and the training of people involved in these activities, agreed by the air conditioning and refrigeration industry.

Refrigerant guidelines

Refrigeration installations must be inspected and maintained regularly and rigorously by specialists. Their activities must be overseen and checked by properly trained people.

To minimise discharge to the atmosphere, refrigerants and lubricating oil must be transferred using methods which reduce leaks and losses to a minimum.

•Leaks must be repaired immediately.

•Service valves fitted to the flow and return lines permit charge transfer to a suitably arranged external container.

•It is indispensable to use a dedicated transfer station.

•Compressor lubricating oil contains refrigerant. Any oil drained from a system during maintenance must therefore be handled and stored accordingly.

•Refrigerant under pressure must never be discharged to the atmosphere.

Recharging liquid refrigerant

CAUTION:

30RA-RH units are charged with liquid HFC-407C refrigerant.

This non-azeotropic refrigerant blend consists of 23% R-32, 25% of R-125 and 52% R-134a, and is characterised by the fact that at the time of the change in state the temperature of the liquid/vapour mixture is not constant, as with azeotropic refrigerants.

All checks must be pressure tests, and the appropriate pressure/ temperature ratio table must be used for the interpretation of the values.

Leak detection is especially important for units charged with refrigerant R-407C.

Depending on whether the leak occurs in the liquid or in the vapour phase, the proportion of the different components in the remaining fluid is not the same.

NOTE:

Regularly carry out leak checks and immediately repair any leak found.

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