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Alpha HE CB/SY
1. CENTRAL HEATING THERMOSTAT
This thermostat controls the temperature of the water leaving the boiler for the heating system. For maximum output from the
radiators the thermostat should be turned fully clockwise i.e. maximum output. If lower heating temperatures are required, turn the
thermostat anti-clockwise.
2. DOMESTIC HOT WATER THERMOSTAT - HE CB25/33 only
This thermostat controls the temperature of the domestic hot water leaving the boiler. For maximum hot water temperatures the
thermostat should be left at maximum i.e. fully clockwise. If lower temperatures are required, turn the thermostat anti-clockwise.
3. SELECTOR SWITCH
This control allows the boiler to provide central heating and hot water or hot water only.
Note: The internal clock and frost thermostat will not operate when the switch is in the vertical position, i.e. 'Off' position (0).
4. PRESSURE GAUGE
This indicates the central heating system pressure. It should always be within the green band when cold, increasing slightly
when hot.
If the pressure falls below the green band, i.e. lower red area, refer to the label on the inside of the hinged control panel cover
for guidance on re-pressurising the system. Or contact your Installer to have the system checked and pressurised.
Note: The bleeding of radiators will cause the pressure to fall and the system will require re-pressurising after doing so.
5. INDICATOR NEONS
When neon A (red) and neon B (yellow) are illuminated, the following conditions apply:-
Neon
B Flashing very slowly (every 5 seconds) - Electricity supply to the boiler is on.
B Illuminated continuously - Burner is alight.
B Flashing on and off - Temperature sensor fault, contact your Service Engineer.
A Flashing on and off - Overheat or flue thermostat has operated. Rotate selector switch to the reset position (3) to reset. If this
continues to happen, contact your Service Engineer.
A Illuminated continuously - Burner has failed to light. Rotate selector switch to the reset position (3) and the ignition
sequence will restart after a delay of about 30 seconds.
A and B Flashing on and off at the same time - Blocked flue or fan fault, contact your Service Engineer.
A and B Flashing on and off alternately - System pressure is very low and re-pressurisation is required.
A Illuminated continuously and B flashing - Pump fault or restricted flow.
6. OVERHEAT THERMOSTAT
This thermostat automatically switches the boiler off in the unlikely event of the boiler overheating. When the thermostat operates,
the red neon (A) flashes on and off. Rotate the selector switch to the reset position (3) and the boiler will relight.
If this continually happens, contact your Service Engineer.
7. PRESSURE RELIEF VALVE
If the central heating system overheats and steam or water is discharged from the pipe connected to this valve, turn the boiler off
and contact your Service Engineer. Your Installer should have shown you where this pipe terminates, usually outside your dwelling.
8. FROST THERMOSTAT
The boiler has a built-in frost thermostat, which automatically operates the boiler if the water temperature falls below 8°C,
providing the electrical supply is on and the selector switch is set to position (1) or position (2).
3 BOILER CONTROLS