Beretta POWER PLUS Installation Instruction page 50

3 T_out_correct
Outside temperature correction (parameter 39)
Normally the value displayed is the value read by the micro-controller, plus or minus a correction value
(T displayed = T read by the probe +/- correction).
The outside temperature value read can be corrected by changing the value of parameter 39, (the limit allowed for
the correction is +/- 30 °C). In this phase, the use of a reference thermometer is suggested.
Pre-set to 0.
4 T4_frost_protection
Frost protection (parameter 35)
The electronic controller features a frost protection function that is also active in standby. The frost protection function
has two levels, the first that starts the pump, and the second that starts the pump and the burner.
If the Manifold Temperature ≤5°C, the pump in the high temperature circuit and the loop pump are started, or, when
CH_type=1 and the outside probe is connected, if the Outside Temperature ≤3°C (par. 35), the pump in the high
temperature circuit and the loop pump are started.
If after 10 minutes the Manifold Temperature ≤5°C, a burner is started at maximum output, until
the Manifold Temperature ≥20°C.
If after 10 minutes the Manifold Temperature ≥5°C but, when CH_type=1 (Par. 14 or 22) and the outside probe is
connected, the Outside Temperature ≤3°C (par. 35), the pump continues operating until the Outside Temperature
≥3°C.
Pre-set to 3.
50
5 Power_control_mode
Cascading management (parameter 33)
To manage the output delivered by the system, two cascading strategies are available. In both cases, the Master
controller can only start a new burner when another is already on.
If the Master controller needs to increase the number of burners on, it first checks that the subsequent burner can
be started: no error is present and temperature of the boiler is less than the maximum.
Otherwise, it checks another burner. If no burner is available, the master decreases the number of burners to be
started.
MODE: MINIMUM NUMBER OF BURNERS ON (PAR. 33=0)
The output of the system is modulated by a PID control algorithm, where the value controlled is the temperature in
the manifold, and the set point refers to the active circuit (set point in the high or low temperature circuit, or DHW set
point). The PID control directly manages the last 2 burners started, while the previous burners operate at maximum
output.
If the Manifold Temperature < set point – 5°C, the next burner is started, and both are managed by the PID control
algorithm.
The Master controller waits 30 seconds, and then if the Manifold Temperature < set point - 5°C, another burner is
started.
The first burner works at maximum output, while the other two are managed by the PID control algorithm.
If the Manifold Temperature > set point + 2°C, the last burner is stopped, the other two most recently started burners
are managed by the PID control algorithm, while the others work at maximum output. The Master controller waits 30
seconds before checking the situation again.