Dehydrationofcircuits
This operation must be carried out with all valves open (including solenoid valves) with connection to a vacuum pump:
of the low pressure side and of the high pressure side.
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.
This is to prevent motor windings damage.
Oil Level Check
Afteraminimumof2hoursofoperation,check the oil compressor
levels.
☺
¾sightglassworking.
Levels should never exceed the manufacturers’ recommendations.
Oils
The compressor Manufacturer's recommendations should be followed according to the type of refrigerant.
The use of colorants or UV tracers as leak detectors in the oil, is not allowed.
Oil
Refrigerant
Mobil Arctic EAL 22 CC
ICI Emkarate RL32CF
R404A
This table is not exhaustive, but summarises the principal oils used. If any other oil is to be used, we would advise contacting
PROFROID or the compressor manufacturers.
RefrigerantFluidCharge
It is possible to charge in liquid phase when the installation is under vacuum through the charging valve provided on the liquid
receiver (depending on models).
The charging bottle must remain connected to this valve permanently during the whole start-up period to enable instant adjustment
while charging the installation.
Pre-SettingAndCheckingofSafetySystems
Pre-set the LP (Low Pressure) pressure switches (following application guideline from manufacturer of compressor) and test
manually. Do not set these below atmospheric pressure.
Pre-SettingAndCheckingofcontrolsystems
Pre-set the LP and HP pressure switches and test manually.
Start-up
of
compressors
-
Open all the valves (compressor suction and discharge in liquid bottle)
-
Place an ammeter on one phase of the compressor
-
Close the power circuit-breaker or the fan motor cut-outs.
-
Start up compressor by switching the on/off switch toon.
The current increases to maximum and must decrease very rapidly. If this does not happen, stop the compressor to check and
find the fault.
Repeat these operations for each compressor.
Remainder
of
charge
Fill up with the remainder very quickly.
An incomplete charge of fluid will cause considerable superheat and so abnormally high discharge temperatures.
Fan
checks
Direction of rotation
Check that the fans are rotating in the correct direction, i.e. drawing on the coil.
Fan operation
The fans cut in/out from the collectors towards the end of the coil.
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