Emergency Stop; Extended Machine Inactivity; Start-Up After Extended Machine Inactivity; First Diagnostics - Mitsubishi Electric w-MEXT 006 Installations, Bedienungs Und Wartungsanleitungen

w-MEXT
MICROPROCESSOR DISPLAY
Microprocessor: manages the operation process, with the possibility of setting parameters
and monitoring operating conditions.
The operating details of the machine and interfaces can be found in the User Manual.
5.3

EMERGENCY STOP

Considering that there are no directly accessible moving parts in the machine, there is no
need to install an emergency stop device.
In any case, if installed this device would not reduce the risk as the emergency stop would
be identical to the normal stop using the main switch.
5.4

EXTENDED MACHINE INACTIVITY

In case of extended machine inactivity (e.g. seasonal shutdown), the specialist Engineer
must:

carry out a leak test on the system

opening of the line circuit breaker

Closing of the chilled water shut-off valves

Draining of water from the hydraulic circuit pipes
5.5

START-UP AFTER EXTENDED MACHINE INACTIVITY

Before starting the machine, carry out all the maintenance activities. The specialist Engineer
must also carry out adequate checks, calibrations and the start-up procedure.
6

FIRST DIAGNOSTICS

6.1

WHAT TO DO IF ...

List of actions to be taken in case of unit fault.
Fault Cause
Setting Decrease the setpoint
Check that the machine is not
Incorrect unit
Ambient
undersized for the thermal load or
temperature selection
the air volume handled
too high
Check the probe reading
Fault
Check for alarms
Setting Increase the setpoint
Check that the machine is not
Incorrect unit
undersized for the thermal load or
selection
the air volume handled
Check the probe reading
Ambient Fault
Check for alarms
temperature
Check the power supply to the
too low
Hot heaters (if applicable)
Resources
Check the heater safety
thermostat
Cold Check the operation of the
Resources freecooling damper (if applicable)
Setting Decrease the humidity setpoint
Check that the machine is not
Incorrect unit
undersized based on the latent
selection
Ambient load
humidity too Fault Check the humidity probe reading
high
Check the operation of the
Humidifier
humidifier
Check that the thermal expansion
Cooling circuit
valve is working correctly
Setting Increase the humidity setpoint
Incorrect unit Check that the machine is not
Ambient
selection oversized based on the latent load
humidity too
Fault Check the humidity probe reading
low
Check the operation of the
Humidifier
humidifier
Check the speed settings of the
fans
Setting Check the air flow setpoint or the
delta P in case of variable
adjustments
Check the power supply to the fan
Check the analogue output of the
Low Air speed reference from the
Flow controller
Check the reading and positioning
Fan of the differential pressure
transducer in case of variable
adjustments
Check for system load losses
Check the cleanliness of the unit
filters
UM_w-MEXT_01_Z_10_20_ML
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7

MAINTENANCE

7.1

MAINTENANCE INSTRUCTIONS

OBLIGATION
Both regular and extraordinary maintenance activities must be
carried out by AUTHORISED TRAINED INDIVIDUALS equipped
with all the necessary personal protective equipment.
The machine site of installation must meet all the safety
requirements
The procedures set by the Manufacturer must be followed.
Before any kind of maintenance is carried out the following measures must be observed:

isolate the machine from the power supply using the yellow/red switch on the main
door, which can be padlocked in the "open" position;

hang a "Maintenance - do not switch on" sign on the main switch;

use appropriate personal protective equipment (for example: helmet, insulating gloves,
protective goggles, safety shoes, etc.);

use tools that are in good condition and be sure to be familiar with the instructions
before putting them into practice;
Whenever measurements must be taken or checks performed with the machine running, it is
necessary to:

make sure that any remote control systems are disconnected; be aware that the PLC
on the machine controls these and can enable and disable the components, posing a
degree of danger (for example, by powering and running the fans and their mechanical
systems, which can drag);

work on the open electrical panel for as short a time as possible;

close the electrical panel as soon as the single measurement or check has been
performed;
Furthermore, the following precautions must always be taken:

take measures to protect yourself from any leakage of fluids at dangerous
temperatures during bleeding;

when replacing electronic boards, always use suitable equipment (extractor, antistatic
bracelet, etc.);

if replacing a motor, coils or other heavy components, make sure that the lifting
equipment is suitable for the weight;

do not access the fan compartment without first isolating the machine by means of the
disconnecting switch on the electrical panel and clearly displaying a sign saying, "Do
not operate - maintenance in progress";

always use only original spare parts purchased directly from the Manufacturer or from
official dealers;

before closing and restarting the machine, make sure to remove all tools or foreign
bodies.
The list of scheduled maintenance operations is shown in the next paragraph of this manual.
For each intervention, both of ordinary and extraordinary maintenance, a special form must
be issued and kept by the user.
If a Scheduled Ordinary Maintenance notebook is available on the machine, all the operations
carried out must also be recorded on the same.
7.2

SCHEDULED MAINTENANCE

Carry out all the scheduled maintenance activities at the indicated intervals.
INFORMATION
Failure to carry out regular maintenance will make the warranty null
and void and relieve the manufacturer of all safety related
responsibilities
The scheduled maintenance activity intervals are indicated in the tables on the following
pages.
To "read" the hours of operation, they must be displayed on the microprocessor display.
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TRANSLATION OF THE ORIGINAL INSTRUCTIONS
English