M02R40C8-00 29/07/08 page 21
8. CONTROL OF THE 3-WAY VALVE FOR DOMESTIC HOT WATER
8
1
CN2
121110987654321
gnd
CN1
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
35791113
2468101214
135791113
24681214
15
16
+5 V
Tx
Rx
DTR
GND
Domestic hot water can be produced in summer and winter, based on an
external request, by controlling a dedicated 3-way valve.
When the contact is closed, the valve switches to the domestic hot water
storage and the unit changes its working set point to the domestic hot water
set point (par 117).
The passage from DOMESTIC HOT WATER mode to COOLING (or vice
versa) is timed and occurs only when the temperature of the water has
dropped below the safety limit defined by parameter 108.
Similarly, in the passage from DOMESTIC HOT WATER to HEATING the
switching occurs when the temperature of the water has increased beyond
the safety limit defined by parameter 109.
This function requires the optional plug-in expansion module that must be
assembled by the customer (refer to the instructions in the kit ) and enabled
with the parameter 140 = 1.
To enable the DOMESTIC HOT WATER management in summer as well,
par. 119 must be = 1
If the DOMESTIC HOT WATER set point is satisfied but the external
request remains active, the INCONGRUENT THERMOSTAT C36
shutdown is signalled: the domestic hot water boiler thermostat must be
set to the same value as the domestic hot water set point of the machine.
If remote control will also be used for the SECOND SET POINT, it is
necessary to set par. 50 = 2. In this mode the inputs on the main card will
be configured as follows:
• CN1_10/11 domestic hot water request
• CN1_14/16 second set point
Refer to the wiring diagram to identify the corresponding terminals
PLUG IN module
262524
23
22 302928
27
CN3
1357911
2
4681012
par Description Meaning value
49 Comando2°Set Mode control 2° set point by parameter 0
50 EnH2OSanitaria Enabling domestic hot water valve management 0
108 TlimiteCool H2O input value below which the compressor is enabled in cool mode 21
109 TLimiteHeat H2O input value above which the compressor is enabled in heat mode 25
117 SetH2OSanitaria Set Point domestic hot water 35
119 ModeEnable Configure operation mode
140 PlugInEn Enables the PLUG-IN presence. 1=YES / 0=NO
With par. 50 = 1 the management becomes the following:
• CN1_10/11 unconfigured
• CN1_14/16 second set point / domestic hot water
MODE
INPUT
2° set point on the
main board
VALVE POS. SET POINT 2° SET POINT
HEATING ON to the installation set heat
2° set point heat *
DOMESTIC HOT
WATER
OFF to the boiler SetH2OSanitary Not manageable
COOLING ON to the installation set cool
second set point cool
*
In this mode the 2nd set point (ECO) cannot be enabled by remote consent; it can be enabled from the LED keypad with the
ECO key or by setting parameter 49 = 1
DOMESTIC HOT WATER: COMPENSATION OF THE SET POINT FOR EXTERNAL TEMPERATURE
The set point can be compensated according to the external temperature in 2 modes:
1) hot season thermal efficiency curve
when the external temperature is high, the domestic hot water set point is decreased; in this manner the thermal efficiency
is increased
curve A in the graph
the compensation is enabled in the standard configuration
2) compressor operation limit
when the external temperature is particularly cold, the domestic hot water set point is decreased in order to guarantee
operation of the compressor even near its operation limits
curve B in the graph
the compensation must be enabled during start-up
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