Alpha CD28C - Description and Boiler Specifications; Boiler Types and Capacities

2
Alpha CD25C/28C/35C
1. CENTRAL HEATING THERMOSTAT
This thermostat controls the temperature of the water leaving the boiler for the heating system. For maximum efficiency from
the boiler the thermostat should be left at number 6 as shown in Fig. 1. If lower heating temperatures are required, turn the
thermostat ant-clockwise. If higher temperatures are required, turn the thermostat clockwise.
2. DOMESTIC HOT WATER THERMOSTAT
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.
The Alpha CD range of high efficiency condensing combination boilers are wall mounted, fan assisted room-sealed boilers.
The CD25C, CD28C and CD35C are combination boilers providing both central heating and domestic hot water at mains pressure.
The CD25C boiler is suitable for central heating loads of between 5.5 and 19.5 kW (18 780 and 66 550 Btu/h).
The CD28C boiler is suitable for central heating loads of between 6.3 and 25.9 kw (21 500 and 88 400 Btu/h).
The CD35C boiler is suitable for central heating loads of between 7.8 and 30.3 kw (26 600 and 103 400 Btu/h).
The boilers will provide central heating (as required) during the 'on' times set on your clock (if fitted). Hot water is always
available from the boilers whenever a hot tap is opened and takes priority over the central heating.
The burner is lit electronically.
Fig. 1
3 BOILER CONTROLS
2 USER CONTROLS
1 DESCRIPTION
Pull the controls panel cover forward and down to gain access to the controls.
0
1
2
3
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
bar
04
3
2
1
RESET
A
D
B
C
SELECTOR THERMOSTAT THERMOSTAT
OFF
Clock (if fitted)
Indicator
Neons
Selector Switch
Domestic
Hot Water Thermostat
Central
Heating Thermostat
System
Pressure Gauge