Major System Components And Operation Data; Compressors; Lubricant; Evaporators And Condensers - Carrier Aquasnap 30RW Installation, Operation And Maintenance Instructions

14 - MAjOR SySTEM COMPONENTS AND
OPERATION DATA

14.1 - Compressors

30RW/30RWA units use hermetic scroll compressors. The
only refrigerant permitted for these compressors is R-407C.
30RWA split units operating with an air-cooled condenser,
are supplied with the refrigerant circuit and consequently
the compressor under nitrogen pressure between 0.3 and 1
bar.
The compressors are not certified for mobile applications
or use in explosive environments.
IMPORTANT: All compressor and system pressure tests
must be carried out by qualified personnel, taking the
greatest care with potential dangers resulting from the
pressures used, and respecting the maximum operating
pressure limit on the high and low-pressure side, shown
on the unit and compressor name plates.
• Maximum operating pressure, low-pressure side for
compressors DQ 12 CA 027 and DQ 12 CA 028: 20 bar
• Maximum operating pressure, low-pressure side for
compressors DQ 12 CA 025 - DQ 12 CA 001 - DQ
12 CA 002 - DQ 12 CA 031 - DQ 12 CA 032: 25 bar
• Maximum operating pressure, high-pressure side for
compressors DQ 12 CA 025 to DQ 12 CA 028: 32 bar.
For certain units incorporating compressors with different
maximum operating pressures on the low-pressure side in
the same refrigerant circuit, the lowest maximum pressure
should be taken into consideration.
Any modification or alteration such as soldering on the
compressor shell may invalidate the right to use the
equip-ment.
30RW/30RWA units using these compressors are installed in
areas where the temperature must be between 5°C minimum
and 40°C maximum. The temperature around the compres-
sors must not exceed 50°C during unit shutdown cycles.
Shock absorbers are installed under the compressor feet.
Tighten the rubber shock absorbers until there is contact
between the flat washer and the steel bar.
Scroll compressors are unidirectional, and refrigerant
com-pression is only ensured, when the phase order is
followed. Compressors DQ 12 CA 025 to DQ 12 CA 032
incorporate reverse rotation protection. If reverse rotation
is not cor-rected by reversing the phases, the compressor
will cut out via the internal motor protection.
For compressors DQ 12 CA 027 and DQ 12 CA 028 a phase
order control function is incorporated in the external motor
protection module.

14.2 - lubricant

The compressors have the following factory lubricant charge:
polyolester oil (reference: MAN-7754024_EE).
This lubricant must not be mixed with any other type of
lubricant.
When 30RWA units are connected to the remote air-cooled
condenser, opening the circuit to the atmosphere must be
minimised (less than half an hour). The connection of the
discharge piping must be fast to prevent contamination of
the lubricant with moisture.
Check that the oil level is between 1/4 and 3/4 in the sight
glass before start-up and after normal unit operation.
If an additional oil quantity is required to compensate the
initial low level in the compressors (due to the piping length
between chiller and air-cooled condenser), top up the charge,
using only the permitted lubricant shown on the compressor
name plate: polyolester oil (ref: MAN-7754024_EE).

14.3 - Evaporators and condensers

The evaporators and condensers are plate heat exchangers.
They are tested and stamped for a maximum operating
pressure of 3200 kPa on the refrigerant side and 1000 kPa
on the water side.
The heat exchanger sizing for the whole range ensures a
saturated evaporating temperature of 5.5°C and a conden-
sing temperature of around 45°C with actual subcooling of
around 8 K at the condenser leaving side, based on nominal
Eurovent conditions.
The evaporators and condensers are single-circuit for sizes
30RW/RWA 020 to 150 and interlaced dual-circuit for sizes
30RW 160 to 300.
The water connections between the heat exchangers and the
piping of the hydronic modules have quick-connect Victaulic
couplings to facilitate pump disassembly, if required.
The control thermistors can in some cases be included in
the heat exchangers themselves. This depends on the heat
exchanger type and the number of plates used.
A drain with a 1/4 turn valve is included in the leaving
water of all heat exchangers.
The evaporators have 19 mm thick polyurethane foam
thermal insulation. For option 150 (heat pump), the conden-
sers also have 19 mm thick polyurethane foam thermal
insulation.
The products that may be added for thermal insulation of the
containers during the water piping connection procedure
must be chemically neutral in relation to the materials and
coatings to which they are applied. This is also the case for
the products originally supplied by Carrier.
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