Control And Operation Devices - Baxi PRIME HT 240 Installers And Users Instructions

18. CONTROL AND OPERATION DEVICES

The boiler has been designed in full compliance with European reference standards and in particular is equipped with the
following
• Safety thermostat
This device uses a sensor on the central heating delivery line to cut off the flow of gas to the burner if the water in the
primary circuit overheats.
If this occurs, the boiler blocks and can only be lit again after the cause of the fault has been eliminated. To relight the
boiler, turn selector (1) (figure 1) to "R" for at least one second.
It is strictly forbidden to disable this safety device.
• NTC Flue sensor
This device is located in the Primary Heat Exchanger.
The main board shuts off the burner when the displayed temperature on the boiler control panel, A5 parameter (see
paragraph 17), is > 110 °C.
To reset the normal operating conditions, turn selector (1 - figure 1) to "R" for at least 1 second.
Note - the reset operation is available if the displayed temperature on the boiler control panel, A5 parameter, is
< 90 °C.
It is strictly forbidden to disable this safety device.
• Flame detector
The flame detector electrode ensures safety in the event of a failure in the gas supply or incomplete ignition of the
main burner.
The boiler blocks in either of these conditions.
To reset normal operating conditions, turn selector (1) (figure 1) to "R" for at least 1 second.
• Water pressure switch
This device ensures that the main burner only ignites if water pressure in the system is above 0.5 bar.
• Pump overrun
The electronic control system keeps the pump operating for 3 minutes in central heating mode after the room tempe-
rature 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.
• 3-way antiblocking valve
If there is no heat demand for a period of 24 hours the 3-way valve switches completely.
• 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 prohi-
bited.
NOTE: Control and safety device functions are only active if the boiler is receiving electrical power and switch 1 (figure 1)
is NOT in position 0.
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INSTRUCTIONS FOR THE INSTALLER