Control And Operation Devices - Potterton WH 46 Installation, Operation And Maintenance Manual

17. CONTROL AND OPERATION DEVICES

The boiler has been designed in full compliance with European reference standards and in particular is equip-
ped with the following
• Overheat thermostat
This thermostat interrupts the gas flow to the main burner in case the water contained in the circuit has ove-
rheated. Under these conditions the boiler locks out and can only repeat the ignition procedure by pressing
of the reset button on the boiler after the cause of the trip has been rectified.
It is 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 con-
tinuously 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 reset button on the boiler.
It is forbidden to disable 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.
• Supplementary pump overrun
After the burner has switched off due to a room thermostat intervention the preset pump overrun of the
pump lasts 10 minutes, when the boiler is in the central heating mode.
• Frost protection device
The 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 supply 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.
• Gas pressure switch
This device enables the main burner only to be switched on if the gas pressure is over 12 mbar.
• Hydraulic pressure sensor
This device enables the main burner only to be switched on if the system pressure is over 0.5 bar.
INSTRUCTIONS PERTAINING TO THE INSTALLER
30
926.772.1 - GB/IE