Startup And Adjustment - Arneg HPF Serie Guía De Instalación Y Manejo

13. Startup and adjustment

Putting the system under a vacuum
Use of a "High Vacuum" pump and a vacuummeter as indicated in the instructions ISQ006 is required.
Do not use the compressors of the refrigerator system to create the vacuum.
- Connect the "High Vacuum" pump to all the refrigerator systems on the high pressure side and on the low
pressure side.
- Make sure any mechanical parts (e.g. taps), electric parts (e.g. solenoid valves) are fully open and the air flow
is not obstructed in any way in the unit.
- When the vacuum meter indicates a pressure of 1 mbar, stop the vacuum pump.
- Control for at least 12 hours that the pressure does not increase beyond 2 mbar.
At this point, the system can be considered to have a perfect seal.
- 6 hours after stopping the pump (time necessary to stabilize the system) take note of the "pressure
developments" for at least 24 hours.
Important: If at the beginning the pressure rises in a regular way and stabilizes at a value
corresponding to the saturation tension of the residual water at room temperature it
means the system is sealed but still contains some water. If the pressure does not
stabilize but continues to rise, it means the system in addition to containing water, is not
sealed. In both cases, the operation has to be repeated taking care to eliminate the leaks.
- If over a period of 24 hours the pressure does not exceed 0.5 mbar the system can be considered dry
and perfectly sealed.
Note: This value is valid for any volume of system. It is a mistake to think that for high volumes values higher
than 0.5 mbar are acceptable.
Note: All these operations should be carried out by specialized technical personnel only.
Filling with coolant
This operation should be done after the system has been declared perfectly sealed.
- Connect the tank (create a vacuum also in the connecting pipeline) to the high pressure circuit using the
connector between the condenser and the liquid reserve.
- Fill through the connector with the contents of tank in the liquid stage.
- Fill, changing tanks when empty, until the pressures between the tank and the system are equal. With the
pressure balanced it will no longer be possible to fill through this connector.
- On tanks with two connectors do not overturn the tank.
- Connect the liquid stage of the tank to a connector on the intake line.
- Since it is impossible to create a vacuum in the section of pipeline of the tank, connect the pipeline and make
sure there is coolant in the pipe.
- Switch on a compressor so as to reduce the pressure in the intake circuit, open the tap on the tank and finish
filling.
Danger: This step is the most dangerous as an excess capacity of coolant may cause a backflow of
excessive liquid to the compressor and damage it.
Pay attention to the discharge temperature of the compressor (over 50°C) and the temperature
of the oil tank (10°K above the evaporation temperature).
To reduce this risk it is possible to fill the system through a connector installed downstream of
the liquid reserve after closing the tap on the reserve outlet.
In this way, with the compressor on, the section of pipeline downstream of the reserve will
reduce its pressure to enable the liquid in the tank to migrate towards the system.
This operation can trip the high pressure switch, so make sure to check the condensation
pressure value.
- Finish filling until the liquid level indicator on the reserve outlet is full.
Note: During the winter when the condensation temperature is particularly low it is possible to overload the
system.
- Make sure the undercooling of the liquid at the condenser outlet is 5°K.
During the summer, resume correct filling.
For the operations of startup and adjustment of the unit, consult the manual "Operation and Programming of the
Control Panel".
To start the unit, turn the main switch on the power panel and program the unit.
05060044 00 15/07/2004
HPF
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