Carel uAM, User Manual

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µAM +030220460 rel. 1.0 - 08.05.2007 18
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How it works
Once the function has been enabled, when setting AUTO, µAM will analyse the control signals (heating/coo-
ling) from the master e-drofan units that are ON and have no alarms and:
will stop the unit for the production of cold water (chiller) if all the units require hot water;
will restart the unit for the production of cold water (chiller) if at least one unit requires cold water;
will stop the unit for the production of hot water (boiler) if all the units require cold water;
will restart the unit for the production of hot water (boiler) if at least one unit requires hot water;
An active unit in any case requires a certain amount of energy to keep the water at the desired temperatu-
re, regardless of use. Stopping the unit in question does not necessarily mean energy saving.
To avoid a series of starts / stops that are too close together, µAM will analyse the situation again after
the time set for parameter Ch03 (default 20 minutes); 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.
Other information
This mode is only effective in systems with a high number of master e-drofan units. For systems with just
one or two master units, the Energy Saving function is not recommended, as it may lead to excessive
stops / starts.
4.2.5 Enabling the Automatic changeover function
Enabling this function allows the MODE button to be used to set AUTO mode and activate automatic
changeover. Three types of operating logic are available.
Once the function has been enabled, when setting AUTO, µAM will automatically manage the change in
mode (cooling / heating) on the µC
2 SE and, if Ch01=2, also on all the e-drofan units.
Information
Auto changeover is only available for installations with the following characteristics at the sametime:
- 2-pipe system
- chiller with heat pump controlled by µC
2 SE or chiller and boiler controlled by µC 2 SE
In the instant after a changeover, the water temperature, and consequently the air temperature leaving
the operating fan coils, will not be optimum; it is recommended to fit coil temperature probes on the fan
coils to prevent the e-drofan from activating the outlet of air when the water temperature is not suitable;
The function can be enabled and the behaviour set using parameters Ch01 (enable and type of logic
- see further on: “Operating logic”), Ch02 (minimum temperature delta), Ch03 (minimum time between
two changeovers).
Procedure
To enable the function set parameter Ch01 (to access the parameters see the chapter on “Parameters”),
choosing one of the three possible operating logics (see further on: Operating logic);
Set parameter Ch02 (unless Ch01=3) and parameter Ch03 (for the meanings see further on).
To disable the function, set parameter Ch01 to 0.
OPERATING LOGIC (Ch01= 2, 3, 4)
• (Ch01=2): “Based on the difference between the temperature measured by the µAM probe and the
set point”
How it works
When the µAM is set in AUTO mode, if the temperature measured by the µAM probe is less than the corre-
sponding set point, heating mode is set for the µC
2
SE all the e-drofan units; vice-versa, cooling mode is set.
To avoid a rapid succession of changeovers, µAM changes mode only if both the following conditions are
true:
the ambient temperature must be at least a certain value from the set point (modifiable, 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.
Information
Setting Ch01=2 has the following result:
The ambient temperature set point becomes the same all the e-drofan units and equal to the µAM set
point, which will be shown, in normal display mode, in field 6 on the display (symbol 8 “set” remains
on), see Table 4.c;
any changes made to the set point on a master e-drofan from the acqua or e-droset terminal are igno-
red: every minute µAMets the set point on all the e-drofan units to the same value as its own set point.
Other information
This mode centralises the set point and the heating / cooling mode for all the e-drofan units on the µAM.
The individual master e-drofan units can still be switched OFF using the acqua or e-droset terminal.
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Fig. 4.g