13
DHW function
DHW Comfort functions (pre-heating, DHW recirculation)
The DHW cycle always takes priority over the heating cycle.
DEFAULT SETTING: fixed DHW set point (parameter t06=0)
When DHW cycle activation is requested, due to DHW tapping by the
user (detected by the domestic water flow meter), the regulator
modulates the valve opening in order to adjust the temperature
detected by the domestic water probe to the selected set point value.
When tapping ends, the modulating valve is fully closed.
The DHW cycle ON condition is indicated by the blinking
symbol.
OPTIONAL SETTING: primary return temperature limit
(technical parameter t06 = 1)
When DHW cycle activation is requested, due to DHW tapping by the
user (detected by the domestic water flow meter), the regulator
modulates the valve opening in order to adjust the temperature
detected by the domestic water probe to the DHW set point value if
the return temperature is less than or equal to the set limit. If this
condition is not met, the flow temperature is reduced (by a maximum
of 7°C down to a temperature that can be no less than 40°C), in order
to bring return temperature within the limit values.
Due to the activation of the return temperature limitation
function, DHW temperature can be lower than the set value.
DHW/primary return limit temperature setting
To set the DHW temperature press the <SET> key until the symbol in
the red circle appears; for the return temperature limit press the key
until the symbols in the green circle are displayed. Use the <R> knob
to change the value (*).
The range of possible DHW temperatures is 42–60°C, while the range
of possible return temperatures is 15–45°C.
(*) if these set points cannot be changed you must set parameter t07 to value 0 in the technical menu (see “access to technical menu” below).
Parameter t07 = 1 “freezes” the operating set points to prevent inadvertent modifications by the user.
The comfort function can be, alternatively, preheating of the DHW plate
heat exchanger or management of DHW recirculation. They are enabled
by setting to ON or PROG the comfort function (see page 11).
DEFAULT SETTING: DHW exchanger preheating function
(parameter t02 = 0)
During periods when the domestic water cycle is not used, if the DHW
probe detects a temperature 10°C below the SET value, the regulator
partially opens the domestic hot water modulating valve for the time
required (max. 5 min.) to bring the exchanger to the condition wherein it
can assure rapid DHW production.
The active pre-heating cycle is indicated by the blinking
symbol.
This function is of lower priority than any domestic water or heating
cycles.
OPTIONAL SETTING: management of DHW recirculation in the
apartment (parameter t02 = 1)
In alternative to the DHW comfort function it is possible to manage DHW
recirculation, using a similar logic. During periods when the domestic
water cycle is not used, if the DHW probe detects a temperature 10°C
below the SET value, by means of an auxiliary microswitch (see page
19), the regulator closes the circuit supplying the circulation pump (not
supplied) generating a DHW cycle lasting for a pre-set amount of time.
This amount of time is pre-set to 2 minutes. It can be changed by acting
on parameter t09 on the technical menu (1 unit = 10 seconds).
The circulator has to be fed through the auxilliary microswitch so
that the control of recirculation is carried out by the heat
interface unit. DHW recirculation (t02=1) disables the other
functions operating on the auxilliary microswitch described on
page 16. Refer to page 16 for the electrical characteristics of
the microswitch.
Both comfort functions can be enabled according to user defined
weekly time programming. Refer to the remote user interface manual.
N.B.: In the presence of a DHW recirculation system a suitably
sized expansion vessel must be installed.
