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30RA/30RH
GB - 9
ENGLISH
Electrical connections and refrigerant charge
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 mm
2
.
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
———————————————————————————-
Average voltage
Example:
Nominal supply: 400-3-50
AB = 404 V
BC = 399 V
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:
6 x 100 = 1,5 %
400
CAUTION:
The installer must install protection devices, as required by
the applicable legislation.
Motor
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.