Periodic Inspections; Emergency Situations - Arneg MPM 2 Manuel D'installation Et De Service

MPM2 - Medium Power Multisystem
English
- Pressure switch no. 7 delay for start up of compressor no. II after switch over = 60 mn.
- Pressure switch no. 8 delay for start up of compressor no. III after switch over = 90 mn.
- Pressure switch no. 9 delay for start up of compressor no. IV after switch over = 120 mn.
If you want to change these values, it is necessary to adjust the delay devices located inside the control
panel.
Calibration of the general high pressure and safety pressure switch (SRMCR) (Fig. 7)
Devices intended to protect systems under pressure from values that exceed the system's safety limits are
known as "safety accessories."
Directive 9723/EC (PED = European directive for pressurized devices) describes two safety devices:
- device for limiting pressure, such as a safety valve, bursting disc safety devices, buckling rods, controlled
safety pressure release systems (CSPRS);
- limiting devices, which either activate the adjustment system, which closes or closes and shuts down the
system, such as switches activated by pressure, temperature, or fluid level, or safety related measurement
control and regulation devices (SRMCR).
The pressure switches used by Arneg S.p.A. (SRMRC) are classified in Category IV of the PED directive.
The technical file indicates that the maximum allowable pressure (Ps) for the system is 28 bar.
From EN 378-2; Tab. 2, the calibration pressure of the safety pressure switch (without discharge device)
should be less than or equal to the maximum allowable pressure (Ps):
P < 1.0 x Ps
set
P < 0.9 x 28 = 25.2 bar
set
Hence, Pset=25.2 bar is the calibration pressure for the safety pressure switches on the high pressure side
of the system.
For calibration of the low pressure switch, refer to the values found in the table below:
LOW PRESSURE
TN R404a
BT R404a
Calibration of these pressure switches (SRMRC) must be performed by the manufacturer.
If the pressure switches are tripped due to high pressure, they must be manually reset using the reset
buttons.

17.Periodic inspections

Check for proper functioning of the unit every week, as follows;
- First check that the control panel is operating regularly and no indicator light is on;
- Open the door from a safe position (behind and to the side of the door), so as to avoid being struck by any
outflow of hot or cold gas or air;
- Wait a few minutes before looking into the room, in order to allow ventilation through the open door, if
appropriate, activate the forced ventilation system;
- Check for any unusual noises before entering;
- Put on protective ear coverings and enter using caution;
- If you see any stains, leakage, or anything else that indicates malfunctioning, STOP THE INSPECTION
IMMEDIATELY AND EXIT THE ROOM;
- If there are no malfunctions, continue with the inspection.
- Check that the evaporation and condensation temperatures correspond to the planned values
- Make sure that the oil present in the compressor cases is the correct amount and temperature
- Check the level of the coolant inside the liquid container using the indicators, and making sure that the
maximum amount is not reached
- Once the inspection is complete, leave the room in an orderly and clean state.

18.Emergency situations

In the case of unit malfunction, proceed as follows:
- Problem:Electronic control device off
What to do:The safety pressure switch is tripped and the emergency light on the control panel is on
Call technical assistance for restoration of normal operation
- Problem:Error messages on the control panel
What to do:Call technical assistance and report the error message
In all other cases, immediately contact technical assistance to restore normal operation.
34
STOP
Pressure Pe Temperature
(Dew Point) bar (Dew Point) °C
1,5
0,2
DIFF.
Pressure Pe
(Dew Point) bar
-25 0,7
-41,5 0,7
START
Pressure Pe Temperature
(Dew Point) bar (Dew Point) °C
2,2 -22
0,9 -32
05060107 00 03/02/2010