Munters ComDry M190Y, Manual

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6.3. Humidity control
The ComDry dehumidifier is equipped with a sophisticated microprocessor based control system. This,
in combination with the built-in humidity/temperature sensor in the process air inlet, makes it possible to
set both the control and presentation of the humidity to either relative humidity (RH%), dew point (Dp
°C) or absolute humidity (X gr/kg).
The control system additionally checks the temperatures before and after the heater, as well as in the
wet air after the rotor.
A high safety level is obtained by various temperature sensors. Too high temperatures gives a reduction
of the heater power, while excessive temperatures will make the system issue an alarm and shut the
dehumidifier down in a controlled way. For further explanation, see the ComDry Control System Supple-
ment or Quick Guide.
NOTE
The dehumidifier always operates in automatic mode (moisture based operation). As
default it will use the built-in humidity/temperature sensor, as option an external sensor.
6.4. Process fan modes
There are three process fan modes:
Fan
mode
Description
Fan ON The dehumidifier will run the process fan continuously, regardless of if there is a dehumidification need or not.
This is the default mode.
Fan INT INTermittent mode. The fan will stop when the desired humidity (Set Value minus Hysteresis) is reached. If the
humidity reading stays below the Set Value, the process fan will anyhow start after 30 minutes to let the built-
in sensor more accurately sense the condition of the incoming process air. The fan will run for a minute to
produce a proper measurement. If the humidity is still below the Set Value, the fan will stop again. This is re-
peated until the humidity reaches the Set Value, which will make the dehumidification start again.
Fan
DEM DEMand mode. The fan will stop when the desired humidity (Set Value minus Hysteresis) is reached. It will
start again when the sensed humidity is equal to, or greater than the Set Value. This gives in practice a control
with greater hysteresis than “Fan INT”, depending on the following: When the dehumidifier has reached the
desired humidity level, it will shift to stand-by and stop the process fan. After a while, internal machine heat
will increase the temperature of the humidity sensor. This makes the sensor reading even lower, i.e. the sys-
tem functions as if there was a “negative hysteresis”. As a result, a greater humidity load will be necessary to
make the dehumidifier start compared with the “Fan INT” mode.
ComDry M190Y Dehumidifier
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