6
REGULATION LOGIC
6.1 SUMMER/WINTER SWITCHOVER
Four different and alternative logics are pres-
ent to select the thermostat operating modes
according to the configuration set on the
controller:
Ū Local: chosen by the user with the MODE key
Ū Distance: depending on the DI1 Digital Input
status
Ū depending on water temperature
INFO:
In the case of water probe alarm, the
6.2 VENTILATION
6.2.1 General issues
The controller can perform two types of fan
control:
Ū step fan control, with a fixed number of se-
lectable speeds (3 or 4);
Ū modulating fan control, with speeds ranging
from 0% to 100%
Which type of control will be used clearly de-
pends on the type of fan (step or modulating)
installed in the unit. Step control in turn follows
two different logics depending on the type of
valve(s) (ON/OFF or modulating).
Summing up, the automatic control logics im-
plemented by the controller (and described in
detail below) are the following:
Ū 3-speed fan control with automatic step reg-
ulation and ON/OFF valve (or w/o valve), in
cooling and heating modes;
Ū 4-speed fan control with automatic step reg-
ulation and ON/OFF valve (or w/o valve), in
summer and winter modes;
Ū 3-speed fan control with automatic step reg-
ulation and modulating valve, in summer and
winter modes;
Ū 4-speed fan control with automatic step reg-
ulation and modulating valve, in summer and
winter modes;
mode controller returns to the Local mode
temporarily.
Ū depending on air temperature
Where:
Ū Set is the air temperature set using the arrows
Ū ZN is the neutral zone
The thermostat operating mode is indicated
on the display by the COOLING and HEATING
symbols
Ū modulating fan control with ON/OFF valve, in
summer and winter modes;
Ū modulating fan control with modulating
valve.
6.2.2 Natural convection
By enabling the parameter from the configu-
ration menu in units with valve, ventilation in
heating mode is shifted by 0.5°C to permit a nat-
ural convection phase.
6.2.3 Step ventilation
Using the UP/DOWN keys it is possible to select
the following speeds:
Ū AUTOMATIC speed: depending on the set
temperature and the room air temperature;
Ū EXTRA-LOW speed: can be selected only if
the hydronic indoor unit has 4 speeds;
Ū MINIMUM speed
Ū MEDIUM speed
Ū MAXIMUM speed
AUTOMATIC OPERATION FOR 3-SPEED HYDRON-
IC INDOOR UNITS AND ON/OFF VALVE(S) OR
W/O VALVE(S):
1. MINIMUM speed
2. MEDIUM speed
3. MAXIMUM speed
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FC66005977