Control And Operation Devices - Baxi Luna 3+ Operating And Installation Instructions

20. CONTROL AND OPERATION DEVICES

The boiler has been designed in full compliance with European reference standards and in particular is equipped with the
following:
• Flue thermostat for natural draught
This device has a sensor positioned on the left section of the flue extraction hood and shuts off the gas flow to the
burner if the flue duct is obstructed or in the event of draught failure.
Under such conditions the boiler is blocked and the display shows E03 error (see section 9).
To relight the main burner immediately, see section 9.
It is forbidden to disenable this safety device
• Overheat safety thermostat
Thanks to a sensor placed on the heating flow, this thermostat interrupts the gas flow to the burner in case the water
contained in the primary circuit has overheated. Under such conditions the boiler is blocked and relighting will only be
possible after the cause of the anomaly has been removed.
It is forbidden to disenable this safety device
• Flame ionization detector
The flame sensing electrode, placed on the right of the burner, guarantees safety of operation in case of gas failure or
incomplete interlighting of the burner. The boiler is blocked after 3 relight attempt.
See section 9 to RESET normal operating conditions.
• Hydraulic pressure sensor
This device (2 - figure 16) enables the main burner only to be switched on if the system pressure is over 0.5 bars.
• Pump overrun for central heating circuit
The electronically-controlled supplementary running of the pump lasts 3 minutes (F17 - Section 19), when the boiler is
in the central heating mode, after the burner has switched off due to a room thermostat or intervention.
• Pump overrun for domestic hot water circuit
The electronic control system keeps the pump operating for 30 seconds in domestic hot water mode after the D.H.W.
sensor has switched off the burner.
• Frost protection device (central heating and domestic hot water systems)
Boilers electronic management includes a "frost protection" function in the central heating system which operates the
burner to reach a heating flow temperature of 30°C when the system heating flow temperature drops below 5 °C.
This function is enabled when the boiler is connected to electrical supply, the gas supply is on and the system pressure
is as required.
• Lack of water circulation (probable pump jammed)
If the water inside the primary circuit doesn't circulate, the display shows E25 error (see section 9).
• Anti-block pump function
In the event that no heat is required, the pump will automatically start up and operate for one minute during the following
24 hours.
This function is operative when the boiler is powered.
• Three-way anti-blockage valve
In the case of no heat is request for a period of 24 hours the three way valve carries out a complete commutation.
This function is operative when the boiler is powered.
• Hydraulic safety valve (heating circuit)
This device is set to 3 bar and is used for the heating circuit.
The safety valve should be connected to a siphoned drain. Use as a means of draining the heating circuit is strictly prohibited.
Note: domestic hot water is guaranteed even if the NTC sensor (4 - figure 16) is damaged. In this case, the temperature
control is carried out by the boiler flow temperature.
INSTRUCTIONS PERTAINING TO THE INSTALLER
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