Maintenance Of The Integrated Dehumidifier; Temperature And Humidity Probe; Room T+H Probe; Remote T+H Probe - Mitsubishi Electric s-MEXT-G00 006 Technical Manual

TM_s-MEXT_ME28relC_00_12_19_EN
The Alarms and Signals relative to humidifier operation are detailed in the controller alarms section.
A crucial point of humidifier operation is excess current control. In fact, whenever voltage is applied to the boiler electrodes after a period of shutdown, short but very intense
current peaks can be observed.
In the initial period, if excess current occurs, the algorithm responds immediately by removing voltage from the electrodes and performing a forced discharge for
approximately 5/10 seconds, depending on whether a current peak occurs in the first 20 seconds after switch on, or after.
In particular, if there is no current peak in the first 20 seconds the next peak generates a 5 second discharge.
If there is a current peak during the first 20 seconds, a 10 second discharge is performed after the first peak and a 30 second discharge is performed if a subsequent peak
occurs.
If the excess current continues, the humidifier is disabled, a forced discharge is performed and a high current alarm is signalled.
The conductivity of the supply water is measured by the conductivity meter when the inlet electrovalve
is opened (max. measurable value 2000 μS/cm). The low conductivity alarm is generated by the EP-Low production alarm of the CPY module.
The humidifier detects the lack of inlet water (or low flow) and checks whether the current at the electrodes increases after the inlet electrovalve is opened. In this case the
controller displays the no water alarm.
The controller sets parameters b1 and b2 of the CPY to 0 and parameter b5 (conductivity pre-alarm threshold) to 1500 μS/cm and b6 (conductivity alarm threshold) to 2000
μS/cm. For details, consult the CPY controller driver manual.
8.2.9

Maintenance of the integrated dehumidifier

As well as the periodic inspections of the vapour distributor and the water inlet and outlet electrovalves, maintenance of these appliances normally involves cleaning or
replacing the vapour production cylinder. This is generally required for the following reasons:
•
Formation of solid lime scale deposits on the surface of the electrodes due to the temporary hardness of the water: As they are dielectric, these deposits prevent
current from passing through.
•
The storage boiler filling with large pieces of solid waste that occupy the space until they prevent the inlet and outlet water from flowing correctly.
•
Patina of non-conductive substances covering the electrodes due to the foam forming as a result of the possible presence of surface-active agents in the water.
•
Corrosion of the metal electrodes. This phenomenon occurs when the water, rich in aggressive chemicals such as chlorine, is excessively concentrated due to
outflow difficulties or insufficient drainage (softened water is rich in chlorides and should therefore be avoided). In the more significant cases electrical discharges
can take place between the electrodes which amplify the phenomenon as they produce metal particles that dissolve in the water and make it even more
conductive.
•
Possible damage to the boiler walls due to the current that allows the solid deposits to pass and create a short circuit between the electrodes.
To prevent this, the suitability of the water used in the humidifier should always be verified.
In any case, the storage boiler must be inspected once a month and maintenance performed when necessary. Depending on the conditions of the water, maintenance must
be performed after a maximum of 4000 operating hours, after which the "Life timer expired" alarm appears.
Maintenance can involve one of the following two operations:
•
Replacing the storage boiler.
•
Cleaning the storage boiler.
Though it is common practice remove the power from the humidifier and then perform maintenance, the programme still provides the pre-washing and forced draining
procedures under the "Manual" menu as described above.
9

TEMPERATURE AND HUMIDITY PROBE

9.1

ROOM T+H PROBE

This probe is available for all the units that require humidity control.
It permits enabling of the following functions:
•
Dehumidification function
•
Humidification function
It can measure the humidity and the temperature in the room.
The following alarms are associated with the probe:
•
T+H probe address 128 Offline.
• Room temperature probe faulty.
•
Room humidity probe faulty.
The probe is connected to Modbus pCO5+ at the address 128.
9.2

REMOTE T+H PROBE

This probe is available for all the units, but differently from the room T+H probe it is read-only.
It also allows the management of the setpoint offset function.
It permits only the viewing of the humidity and temperature.
The following alarms are associated with the probe:
•
T+H probe address 129 Offline
•
Additional temperature probe faulty
•
Additional humidity probe faulty
The probe is connected to Modbus pCO5+ at the address 129.
Technical manual
TRANSLATION OF THE ORIGINAL INSTRUCTIONS
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