Carel uAM, User Manual

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µAM +030220460 rel. 1.0 - 08.05.2007 19
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• (Ch01=3): “Based on the prevalent requirements of the e-drofan units ”
How it works
When the µAM is set in AUTO mode, all the e-drofan units are set to automatic mode, and the master e-
drofan units that are ON and without alarms are monitored to see which require heating and which require
cooling. The mode corresponding to the majority requirement is activated on the µC
2
SE. If the numbers are
equal, the µAM does not change status.
To avoid a rapid succession of changeovers, µAM changes mode only if the following condition is true:
a set time must have elapsed since the last changeover (modifiable, parameter Ch03); in any case, when
the changeover control signal is received from the µAM, µC
2 SE will make the changes following its own
set times.
Important: as in this case some e-drofan units may operate in a different mode from the mode set by the
µAM
for the µC
2
SE, each e-drofan (both masters and slaves) should read a coil temperature probe to prevent
the fans from being started when the water temperature is not suitable. The installation of a water on-off
valve is especially recommended, to prevent the fan coil from exchanging heat with the environment when
the fan is off (so-called radiator effect).
Note: Setting Ch01=3 or Ch01=4 has the following result:
The µAM in normal display mode shows the temperature measured by the built-in probe in field (6)
(symbol 8 “set” is not shown);
Other information
This mode sets HEATING or COOLING mode for the µC
2
SE based solely on the number of units, without
considering the extent of the deviations between the set point and the temperature measured.
Some zones may be heated only and others cooled only at different times.
Example of operation
master e-drofan #1: probe 16 °C, set point 22 °C, AUTOMATIC mode - heating
master e-drofan #2: probe 14 °C, set point 23 °C, AUTOMATIC mode - heating
master e-drofan #3: probe 21 °C, set point 18 °C, AUTOMATIC mode - cooling
Two units require heating, more than those that require cooling (one); µAM thus sets heating mode on the
µC
2
SE.
Note: master e-drofan #3, if not fitted with a coil temperature probe, will start the fans, as it is in cooling
mode and the temperature measured by the probe is greater than the set point, however the air delivered
will be hot rather than cold, as required.
• (Ch01=4) “Based on the average of differences between the e-drofan probe temperatures and the
corresponding set points”
How it works
When the µAM is set in AUTO mode, all the e-drofan units are set in automatic mode, and then the arithme-
tic average is calculated, with sign, of the differences between the probe readings and the set points of the
master e-drofan units that are ON and without alarms. The mode corresponding to the sign of the average
is activated on the µC
2
SE positive: COOLING, negative: HEATING.
To avoid a rapid succession of changeovers, µAM changes mode only if the following conditions are true:
the average calculated, considered without the sign, must be greater than or equal to a set value (modi-
fiable, parameter Ch02);
a set time must have elapsed since the last changeover (modifiable, parameter Ch03); in any case, when
the changeover control signal is received from the µAM, µC
2 SE will make the changes following its own
set times.
Important: as in this case some e-drofan units may operate in a different mode from the mode set by the
µAM for the external unit, each e-drofan (both masters and slaves) should read a coil temperature probe to
prevent the fans from being started when the water temperature is not suitable. The installation of a water
on-off valve is especially recommended, to prevent the fan coil from exchanging heat with the environment
when the fan is off (so-called radiator effect).
Other information
This mode sets HEATING or COOLING mode in a similar way to when Ch01=3, however also conside-
ring the extent of the differences between the set points and the temperatures measured; this gives more
importance to zones with greater thermal discomfort than those with moderate discomfort.
Some zones may be heated only and others cooled only at different times
Note: See notes for Ch01=3.
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Fig. 4.h
FIG 4.i
= total number e-drofan cooling
= total number e-drofan heating