Mitsubishi Electric w-MEXT, Instructions For Installation, Use And Maintenance Manual

Page: 29 / 242

w-MEXT English
UM_w-MEXT_01_Z_10_20_ML
TRANSLATION OF THE ORIGINAL INSTRUCTIONS
29
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 Solution
Intervention
level
Ambient
temperature
too high
Setting Decrease the setpoint Service
Incorrect unit
selection
Check that the machine is not
undersized for the thermal load or
the air volume handled
Service
Fault
Check the probe reading Service
Check for alarms User
Ambient
temperature
too low
Setting Increase the setpoint User
Incorrect unit
selection
Check that the machine is not
undersized for the thermal load or
the air volume handled
Service
Fault
Check the probe reading User
Check for alarms User
Hot
Resources
Check the power supply to the
heaters (if applicable)
Service
Check the heater safety
thermostat
Service
Cold
Resources Check the operation of the
freecooling damper (if applicable)
User
Ambient
humidity too
high
Setting Decrease the humidity setpoint User
Incorrect unit
selection
Check that the machine is not
undersized based on the latent
load
Service
Fault Check the humidity probe reading User
Humidifier
Check the operation of the
humidifier
Service
Cooling circuit
Check that the thermal expansion
valve is working correctly
Service
Ambient
humidity too
low
Setting Increase the humidity setpoint User
Incorrect unit
selection Check that the machine is not
oversized based on the latent load
Service
Fault Check the humidity probe reading User
Humidifier
Check the operation of the
humidifier
Service
Low Air
Flow
Setting
Check the speed settings of the
fans
Service
Check the air flow setpoint or the
delta P in case of variable
adjustments
User
Fan
Check the power supply to the fan Service
Check the analogue output of the
speed reference from the
controller
Service
Check the reading and positioning
of the differential pressure
transducer in case of variable
adjustments
Service
Check for system load losses Service
Check the cleanliness of the unit
filters
User
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.
MICROPROCESSOR DISPLAY