Control And Operation Devices - Baxi POWER HT 1.850 Manual De Uso Destinado Al Usuario Y Al Instalador

15. CONTROL AND OPERATION DEVICES

The boiler has been designed in full compliance with European reference standards and in particular is equipped with
the following:
• Overheat safety thermostat
Thanks to a sensor placed on the heating flow, this thermostat interrupts the gas flow to the main burner in case the
water contained in the circuit has overheated. Under these conditions the boiler locks out and you can only repeat
the ignition procedure by pressing the reset button on the boiler after you have remedied the cause of the trip.
It is strictly forbidden to disable this safety device.
• Boiler circuit circulation test
The boiler electronic management unit is fitted with a "boiler circulation test" function which involves continuously
checking the primary circuit delivery and return temperatures. In case of an irregular increase in the delivery and
return temperature or a temperature reversal, the boiler stops and signals the error on the display (see error table).
• Flue thermostat
This device, positioned on the flue inside the boiler, interrupts the flow of gas to the burner if the temperature exceeds
90 °C. After verifying the cause of the trip, press the reset button positioned on the thermostat itself, then press the
release button on the boiler.
It is forbidden to disenable this safety device
• Exchanger flange thermostat (260°C)
This device is located on the exchanger flange and interrupts the flow of gas to the burner if the front insulation
yields and overheats the exchanger or the flange gasket develops a fault. Press the reset button on the thermostat,
eliminate the fault and then press the reset button on the boiler control panel.
It is forbidden to disenable this safety device
• Thermal fuse
This device is located at the rear of the exchanger and interrupts the flow of gas to the burner if the rear insulation
yields and overheats the exchanger. If this device cuts in, dismount the exchanger and replace the thermal fuse
(see paragraph "THERMAL FUSE REPLACEMENT OF HEAT EXCHANGER").
It is forbidden to disenable this safety device
• Flame ionization detector
The flame sensing electrode guarantees safety of operation in case of gas failure or incomplete interlighting of the
main burner.
Under such conditions the boiler is locked out.
You must press the reset button on the boiler to restore the normal operating conditions.
• Pump overrun
The electronic control system keeps the pump operating for 3 minutes in central heating mode after the room
temperature thermostat has switched off the main burner.
• Frost protection device
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 as long as the boiler is connected to the a.c. power and gas supplies and the pressure in
the system is as specified.
• Pump-blocking prevention
In case there is no call for heat either from the central heating system or from the DHW system for 24 hours on end
the pump will automatically switch on for 10 seconds.
• Hydraulic pressure sensor
This device enables the main burner only to be switched on if the system pressure is over 0.5 bar.
ISTRUCTIONS PERTAINING TO THE INSTALLER
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