Alpha CD50 User's Instructions

User's

Instructions

Alpha CD50

Wall Mounted, Fan Assisted, Room Sealed, Gas Fired,

High Efficiency, Condensing Combination Boiler with

Unvented Hot Water Storage

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 CD50 G.C. No. 47 532 24

For use with Natural Gas only

Leave these instructions with the User

1 DESCRIPTION

The Alpha CD50 is a wall mounted, high efficiency, fan assisted, room-sealed, condensing combination boiler - incorporating a
52 litre unvented hot water storage cylinder. It provides central heating and domestic hot water at mains pressure.

As supplied, the boiler is suitable for central heating systems requiring between 6.3 and 29.7 kW (21 500 and 101 430 Btu/h).
It will provide central heating (as required) during the 'on' times set on your clock (if fitted). Hot water is always available

whenever a hot tap is opened.

2 USER CONTROLS

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

System

Pressure Gauge

2

1

04

bar

Indicator

Neons

3

Selector Switch

Domestic

Hot Water Thermostat

OFF

0

A

B

C

D

1

2

RESET

3

SELECTOR THERMOSTAT THERMOSTAT

1

9

8

5

7

6

Central

Heating Thermostat

2

3

4

1

2

9

8

3

4

5

7

6

Clock (if fitted)

CD50

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 5 or 6 as shown in Fig. 1. If lower heating temperatures are required, turn the
thermostat anti-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. If lower temperatures are required, turn the thermostat anti-clockwise.
Note: It is recommended that the thermostat is always set between settings 7 and 9.

3. SELECTOR SWITCH

This control allows the boiler to provide central heating and hot water or hot water only. The '0' position will turn the boiler off.

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, ie red area, the system needs re-pressurising. Contact your Installer to have the
system checked and pressurised.

Alpha CD50

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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.
B Flashing on and off - Overheat thermostat has operated. Rotate selector switch to the reset position (3) to reset.
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.
A and B Flashing on and off alternately - 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 to 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 VALVES

If the central heating or hot water system overheats and steam or water is discharged from the pipe connected to the valve or from
the tundish, turn the boiler off and contact your Service Engineer. Your Installer should have told you where these pipes terminate.

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

(1) or (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 (flats on the spindle in line with the valves).
d. The gas and water supplies are on at the mains.
e. The heating system pressure is within the green band as shown on the pressure gauge.

2. Turn the heating and hot water thermostats fully anticlockwise to 0 and set the selector switch to 0.

3. Switch on the electrical supply to the boiler.

4. 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.

5. Set the selector switch to

6. Turn the hot water thermostat fully clockwise. The main burner will light and the hot water storage cylinder will be heated.
After approximately 7 minutes (from cold) the boiler will be ready to provide hot water and the burner will go out.

7. Set the selector switch to
burner will light and the boiler will provide central heating.

8. 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
To turn the boiler off for short periods:- Set the selector switch to

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:- Set the selector switch to 0. 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).

(central heating and hot water) and turn the heating thermostat fully clockwise. The main

(hot water only).

(hot water only).

Alpha CD50

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