Riello ALU PRO power Series Instructions For The Installer And The Technical Assistance Centre page 23

Fuel check valve
The control of the ALU PRO power boiler allows you to
control an external fuel shut-off valve. The function is
activated through parameter C613. When all the modules
are off, if C613 = 1 the fuel shut-off valve is not powered
while if C613 = 0 the valve is always powered.
PROTECTION FUNCTIONS
1 - Boiler temperature limit
If the boiler's outlet temperature reaches the limit value
in parameter C515 all the modules are switched off and
the system pump is started, if the heat request that came
from the heating circuit or the domestic hot water pump,
if the heat request came from the domestic hot water
circuit. The post-circulation remains until the delivery tem-
perature drops 5°C below the value in parameter C515.
2 - Safety temperature
If the delivery temperature reaches the safety value
in parameter C518, the boiler goes into a non-volatile
lockout. All the modules are switched off and there is no
overtemperature dispersal.
3 - Flue gases temperature
If the temperature of the flue gases goes above the value
set in parameter C593 all the modules that are on go to
the output specified in parameter C612.
If, after this, the flue gases temperature goes back below
parameter C593-5°C the modules go back to operating
normally (the boiler restarts from the output in parameter
C612).
If the temperature of the flue gases rises above the
value set in parameter C592 all the modules switch off
and there is a temporary fault. When this fault occurs,
post-purging is activated for 10 minutes (all the active
modules). If after this the temperature of the flue gases
drops 5°C below the threshold specified in parameter
C592 the cascades resumes normal operations.
4 - Control of delivery and return temperature
If the return water temperature exceeds the delivery tem-
perature a temporary error signal occurs; the modules
are switched off and the pumps keep working.
If the return temperature does not drop below the deliv-
ery temperature within 10 minutes, there is a non-volatile
lockout and the pumps are switched off.
5 - Pump anti-block function
If the system pump does not operate for 24h, it is started
for 10s (system pump anti-block).
If the domestic hot water pump does not operate for 24h,
it is started for 10s (domestic hot water pump anti-block).
6 - Module anti-freeze protection
When the delivery temperature drops below the anti-
freeze activation temperature in parameter H511 a heat
request is made to all the modules until the temperature
goes above the anti-freeze deactivation temperature set
in parameter H512. This function is always active.
7 - System anti-freeze protection
The system's anti-freeze protection is active if the param-
eter H556 is set to 1 and there is an outdoor temperature
probe. The control logic is as follows:
- If the outdoor temperature is between -5°C and 1.5°C,
the system pump is switched on for 10 minutes every 6
hours;
- If the outdoor temperature is lower than -5°C, the sys-
tem pump stays on in continuous mode.
8 - Pump test function
The pump test function checks the match between
system pump's operating status and input of the FLOW
SWITCH. The function is active when the parameter
C807 = 1.
- If the primary pump is active and the flow switch input
is closed, then there is no signal (normal behaviour).
- If the primary pump is off and the flow switch input is
open, then there is no signal (normal behaviour).
- If the primary pump is active and the flow switch input
is open,10 seconds from the start of the fault state the
error status is signalled (error code E118), and the
burners are prevented from starting.
- if the primary pump is off and the flow switch input is
closed, 10 seconds from the start of the fault state the
error status is signalled (error code E117), and the
burners are prevented from starting.
When the domestic hot water pump is upstream of the
water equalisation device (parameter C805 = 0), then
the consistency test of the status of the pump is carried
out on both pumps, both the heating circuit one and the
domestic hot water one.
In other cases (parameter C805 ≠ 0), the test is carried
out only for the heating pump.
23
GENERAL