Start-Up Operations; Preliminary Checks; Leakage Testing - Carrier SOPRANO 50 Operating Instructions Manual

motor protection
Electrical
These must be in conformity with the standards applicable and be set according to the nominal current (displayed) for the speed used.
Condensation control by fan cycling
All possible measures should be taken to prevent the motors short-cycling.
Number of cycles allowed: 20 start-ups per hour, allowing 30 seconds between 2 start-ups.

START-UP OPERATIONS

3-

PRELIMINARY CHECKS

At reception of material, make sure that material is under pressure with the help of a manometer.
Ensure that all the threads are fully tightened on fans (jolting during transportation could cause them to loosen), and the tightening of
fans connectors.
Check also if there are any breaks in the piping. (breaks could occur during transportation).

LEAKAGE TESTING

Pressurise the whole system, using a neutral gas (Nitrogen) with a (non-liquid, non-colorant) tracer at a minimum pressure of 10 bars and
at a maximum pressure below 20.5 bars, isolating the LP (low pressure) switches.
Important
: If the LP (low pressure) circuit is fitted with a safety valve (e.g.: on the suction accumulator) the test pressure on that part
of the circuit should be approx. 20% below the operating pressure of this valve.
Thorough leakage detection using a suitable detector should be carried out on the condenser unit.
DEHYDRATION OF CIRCUITS
This operation must be carried out with all valves open (including solenoid valves) with connection to a vacuum pump of the HP and LP
sides.
The quality of drying should not be judged by the speed at which the level of vacuum is reached but on the effective time it is
held (24 hours at 0.7 mbar is a good standard).
The total increase in pressure during that period should not be more than 2.6 mbar.
The residual moisture in the system should be less than 20ppm.
When the installation is under vacuum, an insulation check of the motor should not be carried out nor should the compressors be
started before at least 1 bar of fluid pressure is reintroduced. (To prevent motor windings damage).
FAN CHECKS
Check that the fans are rotating in the correct direction, i.e. drawing on the coil.
 Fan operation
When pressure regulated, the condenser fan closest to the collector starts in first, and reversely when shutting down.
START-UP
Currents
Please measure the current absorbed by each motor and compare with the nominal current (displayed), taking into account the network
current.
The current value is stabilized after 10 minutes.
If motors are working with frequency speed control, or if motors are brushless type, please contact us.
START-UP
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