Startup And Adjustment - Arneg MPM 2 Manuel D'installation Et De Service

MPM2 - Medium Power Multisystem
English

15.Startup and adjustment

Putting the system under a vacuum
Use of a "High Vacuum" pump and a vacuum meter is required, as indicated in the instructions
ISQ006. Do not use the compressors of the refrigeration system to create the vacuum.
- For all the refrigeration systems, connect the "High Vacuum" pump on the high pressure side and the low
pressure side.
- Make sure that mechanical parts (e.g. taps) and electrical parts (e.g. solenoid valves) are completely open
and that air flow is not obstructed in any way in the unit.
- When the vacuum meter indicates a pressure of 1.5 mbar, stop the vacuum pump.
- Six hours after stopping the vacuum pump (the time necessary for the system to stabilize itself), take note
of any pressure developments for at least 24 hours.
ATTENTION!: If at the beginning the pressure rises regularly and then stabilizes at a value that
corresponds to the saturation tension of the residual water at room temperature, this
means that the system is sealed but still contains some water. If instead the pressure does
not stabilize but increases, this means the system not only contains water, but is also not
sealed. In both cases, the operation must be repeated, and the leaks must be eliminated.
If over the course of 12 hours pressure does not exceed 0.5 mbar, the system can be considered dry
and perfectly sealed.
Note:This value is valid for any system volume. It is a mistake to think that for large volumes values
that exceed 0.5 mbar are acceptable.
Note:All these operations should be performed by specialized technical personnel only.
Filling with coolant
Before beginning the filling process, it is important to be sure that:
- the system is perfectly sealed and that the pressure test and vacuum test have been carried out
- the safety devices are all operational and appropriately calibrated
- the oil level is as required
- the condenser is operating regularly
This operation must be carried out after the system has been tested to have a perfect seal.
- Connect the tank (creating a vacuum in the connection tubing as well) to the high pressure circuit, using the
connector found between the condenser and the liquid reserve.
- Fill using the connector with the contents of the tank in a liquid state.
- Fill, replacing the tank when empty, until the pressure between the tank and the system is equalized. When
the pressures are equalized, it will no longer be possible to fill from this connector.
- With tanks with two connectors, do not turn the tank upside down.
- Connect the liquid stage of the tank to a connector from the intake line to finish filling.
- As it is impossible to create a vacuum in the tank section of tubing, connect the tubing making sure that
there is coolant inside the tube.
- Turn on a compressor so as to reduce the pressure in the intake line, open the tank tap, and complete the
filling process.
Danger!:This step is the most dangerous, as excess coolant capacity could cause
backflow of excessive liquid to the compressor, damaging it.
Pay attention to the temperature of the compressor discharge (above 50°C) and the
temperature of the oil tank (10°K above evaporation temperature).
To reduce the risk, it is possible to fill the system using a connector located on the liquid
reserve, closing the tap on the reserve outlet.
In this way, with the compressor on, the section of tubing below the reserve will reduce its
pressure, allowing the liquid contained in the tank to move towards the system. This
operation may trip the high pressure switch -- pay attention to the condensation pressure
value.
- Continue the filling process until the liquid level indicator on the reserve outlet indicates that it is completely full.
- Before starting the system, consult the manual for installation and use of the electronic control device.
Operation
Unit operation is controlled by a microprocessor control unit that maintains evaporation and condensation
pressures within the desired values, based on the operation temperatures.
32 05060107 00 03/02/2010