-
-
USER MANUAL
ENGLISH
FAN AND AIR FLOW CHECK (MBS MODELS)
If an ignition request is received, the system checks for the absence of air flow (contact open) of the flue gas pressure
switch, and if the test is passed the fan is activated. When air flow is detected (contact closed) the ignition sequence
is started.
If no air is detected for 15 seconds (e.g. fan failure) a fault is signalled and the system waits for the air detection signal.
Each time the burner is turned off, a post-ventilation cycle is run for 10 seconds.
If a new ignition request arrives during this period, the fan remains active, and if air flow is detected, the re-ignition
phase starts.
In the event of a lock with post-ventilation still in progress, a reset is permitted (the warning disappears), but the boiler can
only be restarted after the system reset time has elapsed.
At each power on/reset, the system automatically checks the type of boiler.
If there is a heat request and air is detected when the fan is off, a fault is signalled.
WATER CHECK
In the case of a boiler/water heater with switching valve, pump circulation is checked via a flow switch connected to the
same inlet as the water pressure switch and the following test cycle is activated. If there is a heat request, the circulator
is activated. If the circulation safety microswitch is switched, the ignition sequence is started. Otherwise, the circulator
continues operating for 6 minutes, after which it is alternately activated for 15s and deactivated for 45s in order to prevent
overheating the circulator. The circulator ON/OFF cycles continue until circulation is detected. If the circulator is inactive
for more than 30 minutes, the first ON cycle is extended to 6 minutes.
The failed circulation fault is displayed during the OFF periods of the circulator. It is not checked whether the circulation
safety microswitch is in short-circuit.
TEST FUNCTION
Activate the function by holding down the INFO button for 10 seconds or by acting on the parameter from the remote
control. While the function is active, the display shows the delivery temperature (blinking) and the symbol “t” while the
burner is driven at maximum power. The function is deactivated when the test function time has elapsed (15 minutes),
or by setting the boiler to OFF. A concurrent sanitary water request activates heat dissipation through the sanitary water
circuit activating the tap symbol on the display.
SENSOR FAULT
In the event of a delivery sensor fault (break or short-circuit), the burner is immediately turned off and the fault signalled.
In the case of operation in heating mode, if the burner was on, a post-circulation cycle is run.
A sensor short-circuit is detected when the resistance is less than about 200 Ohm
A sensor break is detected when the resistance values are Rntc >> 34 Kohm.
In the fast boiler model with plate exchanger, provision has been made for operation with one sensor in the event of a
fault due to failure or short-circuit of the sanitary water sensor. The fault is displayed but the boiler continues functioning
in sanitary water and heating mode.
