Measurement Of Temperature And Humidity; Dew Point And Dehumidufucation Control - MAXA HI-T User's And Installer's Manual

Hi‐T
Centralized controller
Note: If in the chiller is configured the presence of a digital input to the management of the second set point (chiller parameter H44
= 26, terminals SE‐SE, ref. Chiller manual), the management of the humidity control is not done from the remote control.
The digital input is also possibly used for switch between the first and second set point during operation in winter mode.
With double set‐point function enabled, if the chiller works on the second set‐point (radiant panels side), the double set‐point icon
appears in the toolbar of the functions in the pages of chillers and fan coils and it remains transparent.
If, however, the chiller switch to thermoregulate on the first set‐point (fan coil side), the double set‐point icon appears colourful.
Similarly, the entry into dehumidification is marked in the function bar of chillers and fan coils by the transition from transparent
icon to colourful icon.
With parameters H82>1:
DOUBLE SET‐POINT ICON
ICON DEHUMIDIFICATION
In addition, in the home page, you will see a visual indication of activation of the fan coil dehumidification
dehumidification.
).
4.9.1 MEASUREMENT OF TEMPERATURE AND HUMIDITY
The ambient temperature and the relative humidity measured by the sensors built into the Hi‐T remote control, are available to the
chiller, which can then use these values measured for their regulators, where required.
4.9.2 DEW POINT AND DEHUMIDUFUCATION CONTROL
Given the environmental temperature and the humidity, the Hi‐T remote control calculates the dew point.
In operation of the plant in summer mode, with the double set‐point function active on chillers and thermoregulation normally
made with the radiant panels (second set of work), it activates a control to keep the dew point of at least a quantity defined by the
keyboard maintainer parameter Par42/44: " Dew‐point temp. margin "° C below the ambient temperature detected by the control
itself.
Instead, when ambient temperature < Dew Point + Margin temp. Point:
•
The fan coils for dehumidification turn on.
•
The chiller start working with the set‐point for the fan coils.
The permanence remains in this status until the temperature returns to:
Even in the case where the above condition is verified, it remains in the status of dehumidification for at least the time set by
maintainer parameter Par43/44: " Min. staying time in dehumidification", in order to avoid annoying oscillations.
If the above condition is not satisfied after a maximum time given by the maintainer parameter Par44/44: "Max Dehumidification
time ", the machine comes out from dehumidification. To avoid returning immediately, in this case it requires a minimum staying in
adjustment to the radiant panels, still given by Par43/44: " Max. staying time in dehumidification ".
FLOOR SIDE FUNCTION
(2° SET‐POINT)
Table 8. Double set‐point/dehumidification icon.
Ambient temperature ≥ Dew point + Dew temp. margin + 1°C.
FAN COIL SIDE FUNCTION
(1° SET‐POINT)
if dehumidification is active
(
see Figure 9. Fan coil
34