49
COMMISSIONING AND MAINTENANCE
4.2.7
Heat request priority
Priority setting
The parameter 2042 defines the priority between domestic and
heating circuit.
Four modes are envisaged:
0:
Time priority between the two circuits. In case of
simultaneous request, the first priority is assigned to the
domestic circuit for a time period defined in parameter
2043. Once this time period has elapsed, the priority is
assigned to the heating circuit (for the same time period)
and so on, alternately, until the request of one or both
circuits stops;
1:
Priority assigned to the heating circuit;
2:
Priority assigned to the domestic circuit (factory setting).
3:
Parallel. Both circuits operate simultaneously, with the
proviso that the delivery temperature requested by the
DHW circuit must be lower than or equal to the setpoint
requested by the heating circuit. When the temperature
requested by the DHW circuit is higher than the heating
setpoint, the heating circuit pump is turned off and priority
is switched to the DHW circuit.
4.2.8
Special functions
When a special function is active, a specific message is shown
on the display of the device control interface.
Pump activation protection during a Domestic Water request
If during a domestic water request the delivery temperature of
the burner is lower than that of the heater the pump will not be
activated.
Frost protection
The anti-freeze protection function protects the system against
freezing.
When the anti-freeze function is active, the message “AFro” is
displayed.
The intervention modes are the following:
−
Boiler anti-freeze protection (Par. 2074):
If the temper-
ature of the delivery probe of the device drops below 5°C
the burner turns on and stays on until the delivery tem-
perature exceeds 10°C (with the external probe connect-
ed the protection activates only with external tempera-
ture values < 10°C).
−
Heating circuit anti-freeze protection (Par. 2075):
If the
burner stays off for 6 consecutive hours the circulator and
the 3-way diverting valve of the device will activate for 5
minutes. If the temperature of the delivery probe of the
device drops below 5°C the burner turns on and stays on
until the delivery temperature exceeds 10°C (with the ex-
ternal probe connected the protection activates only with
external temperature values < 10°C).
−
Domestic circuit heater anti-freeze protection (Par.
2076):
If the temperature of the heater probe drops be-
low 5°C the burner turns on and the circulator and 3-way
diverting valve will activate. The burner stays on until
the temperature of the heater probe exceeds 10°C and
the circulator carries on working for the post-circulation
time (Par. 2044). With the external probe connected the
protection activates only with the external temperature
values < 10°C.
Venting (Par. 2090)
The function is automatically enabled at the first start-up and at
each reset of the power supply.
When the function is active, the message “Air” is displayed.
During the venting, the circulator is enabled, so that the air
which may be present inside the system circuit can exit through
the automatic drain valve of the device.
The status of the light guide changes to flashing green.
During venting it is possible to deactivate the function by setting
the parameter 2090 = 0
In the event of a low pressure error (40 and 41) or error of the
pressure transducer (42), the bleed cycle is interrupted.
Protection against temperatures that are too high
This function prevents a possible safety thermostat triggering.
If the boiler temperature exceeds the value set in this parameter,
the burner turns off and the circulator continues its operation to
discharge the excessive heat (post-circulation).
Circulator and 3-way valve activation every 24 hours
Every 24 hours the circulator and 3-way diverting valve are acti-
vated for 30 seconds (only in heating mode 0,1,4).
This function prevents the circulator and valve from getting stuck
in a determined position.
Test mode (chimney sweeper)
When this function is enabled (Par. 200 = 1) the equipment works
at maximum power and the 3-way diverting valve switches on
the domestic circuit for a time (which cannot be changed) of 15
minutes, then it goes back to its normal operation.
It is possible to interrupt at any moment the operation in test
mode (Par. 200 = 0). If the delivery probe of the device reaches
82°C (maximum operating temperature) the burner turns off.
When using this function, it is recommended to leave one of the
domestic hot water valves open, in order to discharge excessive
heat.
9
Attention! Hot water runs through the system. Danger of
scalding with hot water!
Anti-legionella function (Par. 2080) - With Heater Probe only
The function is automatically enabled when the heater sensor
is connected, at each power supply reset or daily, if necessary
(factory setting Par. 2080 = 2).
When the function is on, the message “ALE9” is shown next to
the storage tank temperature.
The function increases the water temperature inside the heater
up to 60°C and keeps it for 30 minutes.
Once this time has elapsed, the control box normal operation is
restored.
4.2.9
Flow switch configuration
After connecting the flow switch to terminals 28-29 of terminal
board MO1, set parameter 2027 = 2 (heating flow switch).
