Alpha CD25C, 28C, 35C User's Instructions

User's

Instructions

Alpha CD25C/28C/35C

Range of Wall Mounted, Fan Assisted, Room Sealed,

Gas Fired, High Efficiency Condensing Combination Boilers

For Technical help or for Service call ...

ALPHA HELPLINE Tel: [phone]

website:www.alpha-innovation.co.uk

Nepicar House, London Road,

Wrotham Heath, Sevenoaks,

Kent TN15 7RS

British Gas

Service Listed

Alpha CD25C G.C. No. 47 532 31

0051

Leave these instructions with the User

Alpha CD28C G.C. No. 47 532 33
Alpha CD35C G.C. No. 47 532 35

For use with Natural Gas only

1 DESCRIPTION

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.

2 USER CONTROLS

Pull the controls panel cover forward and down to gain access to the controls.

Clock (if fitted)

Indicator

Neons

Selector Switch

Domestic

Hot Water Thermostat

OFF

0

A

B

C

D

1

2

RESET

3

SELECTOR THERMOSTAT THERMOSTAT

1

2

3

9

4

8

5

7

6

Central

Heating Thermostat

1

2

3

9

4

8

5

7

6

System

Pressure Gauge

2

3

1

04

bar

Fig. 1

3 BOILER CONTROLS

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.

Alpha CD25C/28C/35C

2

5. INDICATOR NEONS

When neons A (red), B (red), C (yellow), D (green) are illuminated, the following conditions apply:-

Neon

D Illuminated continuously - Electricity supply to the boiler is on.
C Illuminated continuously - Burner is alight.
A Flashing on and off - Temperature sensor fault, contact your Service Engineer.
B Flashing on and off - Overheat thermostat has operated. Rotate selector switch to the reset position (3) to reset. If this continues

to happen, contact yor Service Engineer.

B 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 alternatively - System pressure is very low and re-pressurisation is required.
A Flashing and B Illuminated continuously - Pump fault or restricted flow.

Note: Do not hold the selector switch in the reset position (3) for more than 2 or 3 seconds.

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 (B) 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).

4 LIGHTING INSTRUCTIONS

Refer to Fig. 1 for boiler controls.

1. Ensure the following:­a. Electrical supply to the boiler is off.
b. All heating controls and thermostats are set to OFF or minimum position.

c. All isolation valves at the bottom of the boiler are in the open position (slot on the spindle in line with the valves i.e.
d. The gas and water supplies are on at the mains.

e. The heating system pressure is within the green band as shown by the pressure gauge.

2. Switch on the electrical supply to the boiler.

3. Set any room thermostats to maximum and ensure that any clock is in an 'on' position. Refer to section 8, if a clock is fitted
in the boiler control panel.

4. Set the selector switch to

5. Turn the hot water thermostat fully clockwise. Open a hot water tap, the main burner will light and the boiler will provide hot
water. Close the tap and the burner will go out.

6. Set the selector switch to position (2) and turn the heating thermostat fully clockwise. The main burner will light and the
boiler will provide central heating.

7. Set the boiler thermostats, clock, external controls i.e. room thermostat to your chosen settings and the boiler is ready to operate.

To turn the central heating off i.e. in Summer:- Set the selector switch to position (1).
To turn the boiler off for short periods:- Set the selector switch to position (1).

Note: In this position the pump will automatically operate for 5 minutes in every 24 hours. If the water temperature falls below

8°C the built-in frost thermostat will operate the boiler automatically until the temperature of the water in the heating system has
been raised.

To turn the boiler off for longer periods:- Switch off the electrical supply to the boiler. If required, all supplies i.e. gas, water
and electricity may be turned off at the mains. If there is any possibility of the boiler being left during frost conditions, then the
boiler and system should be drained and a label attached to the boiler drawing attention that the system has been drained. If
this is required, contact your Service Engineer.

(hot water only).

).

Alpha CD25C/28C/35C

3