Alpha CD25X, CD28X Installation and Servicing Instructions
Installation and Servicing
Instructions
Alpha CD25X/28X
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: 0870 3001964
Nepicar House, London Road,
Wrotham Heath, Sevenoaks,
Kent TN15 7RS
British Gas
Service Listed
Alpha CD25X G.C. No. 47 532 39
0051
Leave these instructions with the User
Alpha CD28X G.C. No. 47 532 37
For use with Natural Gas only
CONTENTS
1 Introduction ....................................... 2
2 Technical data................................... 3
3 General boiler information..................7
4 Installation......................................... 13
5 Commissioning ................................. 19
6 Boiler operation ................................. 22
8 Component replacement ................... 25
9 Wiring diagrams ................................ 31
10 Fault finding ...................................... 33
11 Short parts list ................................... 37
12 Benchmark Checklist ........................ 38
13 Service record ................................... 39
7 Routine servicing............................... 23
1 INTRODUCTION
The Alpha CD range of high efficiency condensing boilers are wall mounted, fan assisted room-sealed combination boilers.
The burner is lit electronically and the heat output is controlled by a modulating fan and gas valve.
These are combination boilers providing both central heating and domestic hot water at mains pressure.
The boilers are supplied with a pump, pressure relief valve, expansion vessel and pressure gauge fully assembled and tested.
They are designed for use with a fully pumped, sealed and pressurised central heating system using only Natural gas.
The CD25X boiler is suitable for central heating loads of between 5.6 and 19.5kW (19 100 and 66 530 Btu/h).
The CD28X boiler is suitable for central heating loads of between 4.9 and 25.8 kw (16 720 and 88 030 Btu/h).
The maximum output available for domestic hot water is 24.0 kW (81 900 Btu/h), capable of providing 9.6 litres/min for the Alpha
CD25X boiler, 28.7 kW (97 900 Btu/h), providing 11.4 itres/min and for the Alpha CD28X boiler, all with a temperature rise of 35°C.
IMPORTANT
It is the law that all gas appliances are installed by a competent person, ie CORGI registered personnel, in accordance with
the following recommendations:-
Current Gas Safety (Installation and Use) Regulations
All current Building Regulations issued by the Department of the Environment, i.e. Approved Document L1.
Building Standards (Scotland) (Consolidation) Regulations issued by the Scottish Development Department
UK Water Regulations/Byelaws (Scotland)
Health & Safety Document No. 635 (The Electricity At Work Regulations 1989)
The installation should also be in accordance with the following British Standard Codes of Practice:BS 5440:1:2000 Flues
BS 5449:1990 Forced circulation hot water systems
BS 5546:2000 Installation of hot water supplies for domestic purposes
BS 6700:1997 Design, installation, testing and maintenance of services supplying water
BS 6798:2000 Installation of gas fired hot water boilers
BS 6891:1998 Gas installation
BS 7593:1992 Code of Practice for treatment of water in heating systems
BS 7671:2001 Requirements for electrical installations, IEE Wiring Regulations
Reference should be made to DEFRA document 'Guide to condensing boiler installation assessment procedures for dwellings'.
If installation is in a timber framed building, refer to the Institute of Gas Engineers document IGE/UP/7.
This appliance meets the requirements of IPX4D, ie degree of protection against moisture.
This appliance contains no asbestos and no substances have been used in the construction process that contravene the
COSHH Regulations (Control of Substances Hazardous to Health).
Failure to install this appliance correctly could lead to prosecution. It is in your own interest and that of safety to ensure that the
law is complied with.
Manufacturer's instructions must NOT be taken in anyway as over-riding statutory obligations.
Notes: 1. Ensure that the Benchmark Checklist has been completed after the boiler has been installed and commissioned.
2. It is the law that all boiler installations are registered by the installer through the CORGI Gas Work Notification
Scheme.
3. The boiler must only be used with Alpha CD condensing flue components.
Alpha CD25X/28X - Contents/Introduction
2
2 TECHNICAL DA T A
2.1 PERFORMANCE - NATURAL GAS (CAT: I2H 2H - G20 - 20 mbar)
Alpha CD25X
Central Heating
Heat Input (H
)kW
s
(Gross) Btu/h
Heat Input (Hi)kW
(Net) Btu/h
Heat Output (Hs condensing) kW
(50°C/30°C) Btu/h
Heat Output (Hi non-condensing) kW
(80°C/60°C) Btu/h
Differential Burner mbar
Pressure in wg
Room sealed
chamber panel
fitted
Gas Rate m³/h
ft³/h
MAX.
20.4
69 600
18.4
62 780
19.5
66 530
18.0
61 420
3.32
1.33
1.95
68.8
MIN.
5.2
17 740
4.7
16 040
4.8
16 400
4.5
15 350
0.4
0.16
0.6
21.2
Alpha CD28X
Central Heating
Heat Input (H
)kW
s
(Gross) Btu/h
Heat Input (Hi)kW
(Net) Btu/h
Heat Output (Hs condensing) kW
(50°C/30°C) Btu/h
Heat Output (Hi non-condensing) kW
(80°C/60°C) Btu/h
Differential Burner mbar
Pressure in wg
Room sealed
chamber panel
fitted
Gas Rate m³/h
ft³/h
Note: The above appliances are fully modulating and are not range rated.
MAX.
27.3
93 150
24.6
83 930
25.8
88 030
24.0
81 900
6.6
2.64
2.61
92.1
MIN.
5.5
18 760
5.0
17 060
5.1
17 400
4.9
16 720
0.24
0.10
0.53
18.7
Alpha CD25X
Domestic Hot Water
Heat Input (H
)kW
s
(Gross) Btu/h
Heat Input (Hi)kW
(Net) Btu/h
Output to Water (Hs)kW
(modulating) Btu/h
Differential Burner mbar
Pressure in wg
Room sealed
chamber panel
fitted
Gas Rate m³/h
ft³/h
Flow Rate at 35°C Rise L/min
gal/min
Specific Flow Rate (D) at 30°C Rise L/min
(Flow rate @ 30K to EN625) gal/min
MAX.
26.6
90 760
24.0
81 900
24.0
81 900
5.20
2.08
2.54
89.7
9.6
2.2
11.2
2.5
Alpha CD28X
Domestic Hot Water
Heat Input (H
)kW
s
(Gross) Btu/h
Heat Input (Hi)kW
(Net) Btu/h
Output to Water (Hs)kW
(modulating) Btu/h
Differential Burner mbar
Pressure in wg
Room sealed
chamber panel
fitted
Gas Rate m³/h
ft³/h
Flow Rate at 35°C Rise L/min
gal/min
Specific Flow Rate (D) at 30°C Rise L/min
(Flow rate @ 30K to EN625) gal/min
MAX.
31.8
108 500
28.7
97 900
28.7
97 900
8.83
3.53
3.03
106.9
11.4
2.5
13.3
2.9
MIN.
5.2
17 740
4.7
16 040
4.5
15 350
0.4
0.16
0.6
21.2
MIN.
5.5
18 760
5.0
17 060
4.9
16 720
0.24
0.10
0.53
18.7
Alpha CD25X/28X - Technical Data
3
2.2 SYSTEM
Central Heating (Sealed System)
Max. Working System Pressure
Min. System Pressure
Max. System temperature
Pressure Relief Valve Setting
Expansion Vessel Size (pre-charge press.)
Flow Connection
Return Connection
Relief Valve Connection
Recommended System Pressure (cold)
CH Water Temp. (Approx. max.)
2.5 bar
0.5 bar
82°C
3 bar (44 PSI)
8 L at 0.8 bar
22 mm
22 mm
15 mm
1.0 bar
82°C (180°F)
Domestic Hot Water
Max. Mains Inlet Water Pressure
Min. Mains Water Pressure
Min. DHW Flow Rate
Mains Inlet Connection
DHW Outlet Connection
DHW Water Content CD25X
Outlet Water Temp. (Approx. max.)
Flow Regulator Fitted CD25X
2.3 COMPONENTS 2.4 ELECTRICAL
Burner
Main Heat exchanger
DHW Heat Exchanger
Main Burner Injector CD25X
CD28X
Flue - Outer Duct
Flue - Inner Duct
Stainless steel
Stainless steel
Stainless Steel
5.2 mm
5.4 mm
White
Plastic
Supply
External Fuse
Power Consumption
Internal Fuse - Main Terminal
PCB Fuse F1
PCB Fuse F2 and F3
Electrode Spark Gap
Electrical Enclosure Degree of Moisture Protection
CD28X
CD28X
8 bar
0.2 bar
2.5 l/min
15 mm
15 mm
0.2 L
0.26 L
62°C (144°F)
10 l/min
12 l/min
230/240 V ~ 50 Hz
3 A
120 W
F2 A
315 mAT
2.5 AF
3 - 4 mm
IPX4D
2.5 INSTALLATION
Min. Clearances for Servicing Top
(from casing) Bottom
Sides
Front
Flue Terminal Size
Flue Terminal Protruding
Hole Size Required For Flue Assy.
Lift Weight CD25X
CD28X
2.7 PERFORMANCE DATA
%CO2 content (± 0.2%) Sedbuk rating
Boiler model
CD25X
CD28X
Min
9.0
8.9
Natural Gas Efficiency
CH Max
9.4
9.4
235 mm
250 mm
5 mm
450 mm
100 mm Dia.
100 mm
110 mm Dia.
41 kg
42 kg
DHW max
9.4
9.4
2.6 GENERAL
Case Dimensions Height
Gas Connection
Primary Water Content CD25X
Air Duct Diameter
Flue Duct Diameter
SAP efficiency
band
A
A
(%)
90.1
90.0
Width
Depth
Depth (with Jig)
CD28X
NOx class
5
5
720 mm
440 mm
300 mm
340 mm
22 mm
2.5 L
2.8 L
100 mm
60 mm
Alpha CD25X/28X - Technical Data
4
2.8 FLUE LENGTHS
CD Easy-Flue 500 mm with terminal and 90° bend. A CD Easy-Flue 1000 mm with terminal and 90° bend is also available.
CD 750 mm and 1000 mm flue extensions are available.
Length of Flue Required:-
Rear Flue = wall thickness + 140 mm (includes terminal). This is without back frame, add 40 mm if the wall jig is used.
Side Flue = wall thickness + distance between wall and side of boiler + 225 mm (includes terminal)
Vertical Flue = distance from top of boiler side panel to required roof position minus 1000 mm for vertical terminal assembly
Maximum horizontal flue length = 12 m.
Maximum vertical flue length including terminal is 15 m.
Each additional CD 90° Bend is equivalent to 1.3 m of flue length.
Each CD 45° Bend is equivalent to 0.9 m of flue length.
The CD Vertical Flue terminal assembly is equivalent to 1 m of flue length.
2.9 AVAILABLE PUMP HEAD FOR CENTRAL HEATING
Output (50/30°C) Available pump head
kW
25.40
18.70
15.60
12.35
5.30
Btu/h
86 700
64 000
53 000
42 200
18 100
20°C 20°C
metres
2.3
3.5
3.8
4.0
4.6
feet
7.6
11.6
12.6
13.2
15.2
Flow rate
litre/min
16.6
12.6
10.5
8.3
3.2
gal/min
3.7
2.8
2.3
1.8
0.7
This information is based on 20°C system design temperature difference.
Note: For outputs upto 28 kW refer to Section 3.7.
2.10 ELECTRICAL CONNECTIONS
Note: This Appliance Must Be Earthed
An optional integral single channel Clock kit is available if required.
Note: Only use the Alpha single channel clock. Do not fit any two channel clocks.
Blue
Not
Used
Red
Wire
Red
Wire
Brown
Wire
Wire
Internal Clock Terminals
12345
WARNING
1. Ensure wires are connected
correctly
2. Only fit the Alpha recommended
single channel clock. Other
clocks could cause damage.
Clock connections
Fig. 1
Boiler terminal block
Alpha CD25X/28X - Technical Data
5
2.11 BOILER SCHEMATIC
12
34
31
10
19
9
1
23
+
-
8
7
+
11
5
13
20
21
-
14
32
30
33
6
15
16
4
3
35
29
24
Gas
Condensate
discharge
1 - Heat exchanger thermal fuse
2 - DHW flow switch, filter and flow regulator
3 - Diverter valve
4 - Gas valve
5 - Primary temperature sensor
6 - DHW heat exchanger
7 - Main burner
8 - Primary/condensing heat exchanger
9 - Room sealed chamber
10 - Fan
11 - Pressure differential test points
12 - Flue hood
2
22
25
Domestic
hot water
outlet
Cold mains
water inlet
13 - Overheat thermostat
14 - Expansion vessel
15 - Automatic air vent
16 - Pump
17 - Drain point
18 - Pressure relief valve
19 - Primary pressure switch
20 - Ignition electrodes
21 - Flame sensing electrode
22 - DHW temperature sensor
23 - Flue sampling point
24 - Gas service cock
Primary
Heating
return
17
18
27
28
26
Primary
Heating
flow
25 - Mains inlet on/off valve
26 - On/off valve (2 off)
27 - Automatic by-pass
28 - Cyclone separator (if applicable)
29 - Condensate trap
30 - Injector
31 - Venturi
32 - Venturi negative point
33 - Venturi positive point
34 - Flue temperature sensor
35 - Diverter valve motor
Alpha CD25X/28X - Technical Data
6
Fig. 2
3 GENERAL BOILER INFORMATION
3.1 GAS SUPPLY
The Alpha CD25X boiler requires a gas rate of 2.54 m³/h (89.7 ft³/h).
The Alpha CD28X boiler requires a gas rate of 3.03 m³/h (106.9 ft³/h).
The meter and supply pipes must be capable of delivering this quantity of gas in addition to the demand from any other
appliances in the house. The boiler requires at least a 22 mm gas supply pipe.
The complete installation, including the meter, must be tested for gas tightness and purged as described in BS 6891.
3.2 ELECTRICAL SUPPLY
The boiler requires a 230/240 V ~ 50 Hz mains supply, fused at 3 A
The boiler must be earthed.
There must only be one common isolator, providing complete electrical isolation, for the boiler and any external controls.
This boiler has been fitted with a supply cable, however, if it is necessary to fit a cable use PVC insulated cable not less than
0.75 mm² (24 x 0.2 mm) to BS 6500 Table 16. The boiler should be connected to a fused three pin plug and unswitched
shuttered socket outlet (both complying with BS 1363), or a fused double pole switch with a contact separation of at least 3 mm
in both poles.
Wiring external to the boiler must be in accordance with the current IEE Wiring Regulations (BS 7671).
Note: If a room thermostat is fitted, it must be suitable for 230/240 V switching.
3.3 AIR SUPPLY
The boiler does not require any air vents for cooling in the room in which it is installed or when installed in a cupboard or
compartment. The minimum clearances for servicing must always be maintained.
Note: A cupboard or compartment used to enclose the boiler must be designed and constructed specifically for the purpose,
i.e. comply with the Building Regulations.
3.4 FLUE SYSTEM - Fig. 3
The flue system must be installed in accordance with BS 5440:1.
For horizontal flues ensure the Easy Flue assembly is horizontal and the inner duct is sloping downwards towards the boiler.
When additional flue extensions are used, ensure the flue slopes downwards towards the boiler by a minimum of 25 - 30 mm
per metre of flue.
It is recommended that horizontal flue assemblies should be supported approximately every 1.5 m with access provided to the joints.
Flue components are available as follows:CD Easy-Flue 500 mm (includes 90° bend and terminal) - Part No. 6.2000510 (this inludes plume management facility).
CD Easy-Flue 1000 mm (includes 90° bend and terminal) - Part No. 6.2001010 (this inludes plume management facility).
CD 750 mm flue extension - Part No. 6.2000750.
CD 1000 mm flue extension - Part No. 6.2001050.
CD 90° bend - Part No. 6.2000590.
CD 45° bend - Part No. 6.2000545.
CD Vertical flue terminal assembly. Refer to the separate installation instructions supplied with the assembly.
CD Ridge flue terminal assembly. Refer to the separate installation instructions supplied with the assembly.
The following methods determine the correct length of flue required.
For rear exit flue (including terminal) L = B + 140 mm (180 mm if wall jig is used)
For side exit flue (including terminal) L = B + C + 225 mm (min. side clearance required is 5 mm)
For vertical flue L = H - 1000 mm for vertical terminal assembly
Where L = Required flue length
B = Finished wall thickness
C = Distance from the inside wall to the side of the boiler
H = Distance from top of boiler side panel to roof position
Note: 1. If an extra 90° bend is used, this reduces the maximum flue length by 1.3 m. Each 45° bend used reduces the maximum
flue length by 0.9 m.
2. Under no circumstances must the flue length (including allowances for extra bends) exceed 12 metres horizontally and
15 metres vertically.
3. Failure to use Alpha CD flue components with the boiler will invalidate the boilers CE approval, guarantee and may be
unsafe.
4. Further plume management flue accessories are available - refer to the Easy-Flue installation instructions.
Alpha CD25X/28X - General Boiler Information
7
HORIZONTAL FLUE OPTIONS - Lmax = 12 metres
L = B + C + 225 mm
C
B
B
F
E
L = B + E + F + 225 mm + (90° bend = 1.3 metre)
(add 40 mm to 'F' if a jig is used)
L = B + C + E + 225 mm
C
B
E
C
B
VERTICAL FLUE OPTIONS
Not less than
300 mm
H
L = B + C + 225 mm + (2 x 45° bends = 1.8 metre)
Not less than
300 mm
Not less than
300 mm
Not less than
300 mm
H
Hmax=15m
Alpha CD25X/28X - General Boiler Information
8
Hmax = 13.2 m
Fig. 3
3.5 FLUE TERMINAL LOCATION - Fig. 4
J
D
G
HI
Q
Boundary
O
P
N
Fig. 4
Notes: 1.In addition, the terminal should not be nearer
than 150 mm to the framework of an
opening into the buiding, i.e. a window
surround or door surround.
2.This clearance may be reduced to 25 mm
without effecting the performance of the
boiler. However, to ensure the condensate
plume does not affect adjacent surfaces a
clearance of 300 mm is preferable.
3.These clearances may be reduced to 25 mm
without effecting the performance of the boiler.
However, to ensure the condensate plume
does not affect adjacent surfaces the terminal
can be extended beyond gutters, pipes, eaves,
balconies etc. by upto 500 mm. If the flue is
extended more than 500 mm outside, it should
be boxed and insulated.
4.To reduce the possibility of nuisance to
neighbouring buildings etc. it is
recommended the terminal shouild not be
less than 2500 mm from car parking spaces,
building boundary walls, fences etc.
A Directly below an opening, air brick, windows, etc.
B Below gutters, soil pipes or drain pipes
C Below eaves
D Below balconies
E From a vertical drain pipe or soil pipe
F From an internal or external corner
G Above ground, roof or balcony level
H From a surface or boundary facing the terminal
I From a terminal facing the terminal
J Above an opening, air brick, window etc.
K Vertically from a terminal on the same wall
L Horizontally from a terminal on the same wall
M Horizontally from an opening, air brick, window etc.
N Minimum protrusion through a roof
O From a vertical obstruction
P From an openable window
Q From an adjacent vertical terminal
Min. distance (mm)Terminal position
300 (See Note 1)
75 (See Note 3)
200 (See Note 3)
200 (See Note 3)
150 (See Note 3)
300 (See Note 2)
300
600 (See Note 4)
1200 mm
300 (See Note 1)
1500 mm
300 mm
300 mm (See Note 1)
300 mm
300 mm
600 mm
600 mm
Note: A terminal must not be sited under a car port roof
Note: In certain weather conditions the terminal will emit a plume of steam. If possible avoid positioning the terminal where this may
cause a nuisance, i.e. positions A, D, G, H, J or M.
The flue terminal must be exposed to the external air and the position must allow the free passage of air across it at all times.
A terminal must not be sited below 2.1 m where people have access to, such as public footpaths, access routes, patios etc.
However, If the terminal is fitted less than 2.1 m above a surface where there is no public access, the terminal must be
protected by a terminal guard. A suitable guard is available from Alpha Therm Ltd.
3.6 BOILER LOCATION
The boiler is not suitable for external installation unless it is installed within a purpose designed weatherproof building.
The boiler must be installed on a flat vertical wall which is capable of supporting the weight of the boiler. The boiler can be fitted
to or adjacent to a wall comprising of a combustible material without the need for a special thermal insulation barrier.
If the boiler is to be fitted in a timber framed building, it should be fitted in accordance with the Institute of Gas Engineers 'Guide
for Gas Installations in Timber Frame Housing', reference IGE/UP/7.
The boiler may be installed in any room or internal space, although particular attention is drawn to the requirements of the
current IEE Wiring (BS7671) Regulations, and in Scotland, the electrical provisions of the Building Regulations applicable in
Scotland, with respect to the installation of the boiler in a room or internal space containing a bath or shower. Where a roomsealed boiler is installed in a room containing a bath or shower, it must not be possible for a person using the bath or shower
to touch any electrical switch or boiler control utilising mains electricity.
The boiler may be installed in a cupboard or compartment, provided it is correctly designed for that purpose, i.e. complies with
the Building Regulations and the requirements of BS 6798.
Alpha CD25X/28X - General Boiler Information
9
3.7 CENTRAL HEATING SYSTEM - Fig. 5
The boiler is designed for use in a sealed central heating system in accordance with the requirements of BS 5449 and BS 6798.
The system should be designed to operate with flow temperatures of up to 82°C. When designing the system, the pump head, expansion
vessel size, mean radiator temperature, etc. must all be taken into account. Refer to the pump performance table for guidelines.
System volume - The expansion vessel incorporated into the boiler is suitable for a sealed heating system with a maximum
water content of 80 litres (18 gal). Above 80 litres, consideration should be given to fitting an additional expansion vessel fitted
in the position shown in Fig. 5. To check correct operation of the expansion vessel(s) the system pressure should not be more
than 2.5 bar when the system is at maximum operating temperature (for further guidance refer to BS 7074:1).
The boiler is supplied with the following components built in:Pressure relief valve - complying with BS 6759 and set to operate at 3 bar. The discharge pipe must be routed clear of the
boiler and terminated in such a manner that it can be seen, but cannot cause injury to persons or property.
Pressure gauge - To indicate the system pressure to be maintained.
Expansion vessel - Conforming to BS 4814 with a capacity of 8 litres and pre-charged to a pressure of 0.8 bar.
By-pass - The boiler incorporates an automatic by-pass, therefore an automatic by-pass is not required for the system.
Cyclone - This is a device fitted in the heating return within the optional Premier Pack wall jig to remove any foreign or solid
matter etc. from the system.
Make up vessel
Static head of system
Boiler
casing
Automatic
air vent
Additional expansion
vessel (if required)
Double check valve assy.
Filling point
Heating flow
DHW outlet
Mains water inlet
Note: If the mains is fitted with water
meter, check valves or loose jumper stop
cock, then a DHW expansion device must
be fitted.
Note: A drain tap should be installed at the lowest
point of the heating circuit and beneath the appliance.
Heating return
System
drain tap
Fig. 5
3.8 FILLING THE CENTRAL HEATING SYSTEM - Figs. 6, 7
The system design pressure (cold) should be set to 1.0 bar. This pressure is equivalent to a static head (see Fig. 5) of 10.2 metres of water.
Provision should be made to replace water lost from the system. This can be by manual or automatic means, as shown in Figs.
6 and 7. The position for connecting an automatic make-up vessel is indicated in Fig. 5. A double check valve assembly must
be used, as shown in Fig. 7.
Filling of the system must be carried out in a manner approved by the local Water Undertaking. Where allowed, the system
may be filled via a temporary connection as shown in Fig. 6. After filling, always disconnect the flexible hose of the filling loop.
All fittings used in the system must be able to withstand pressures up to 3 bar.
Drain taps (to BS 2879) must be used to allow the system to be completely drained.
Mains
water
supply
Feed cistern to be
located above highest
point in the system
Heating circuit
return
Stop
valve
temporarily connected
Hose
unions
Filling loop
Double check
valve assembly
Test cock
Stop
valve
Mains
water
supply
Heating circuit
return
Double check
valve assembly
Test cock
Overflow
Stop
valve
Fig. 6 Fig. 7
Alpha CD25X/28X - General Boiler Information
10
3.9 FLUSHING THE HEATING SYSTEM
It is essential that the central heating system is thoroughly cleaned and flushed when fitting an Alpha CD boiler. Failure to do so
will invalidate the warranty.
The primary condensing heat exchanger is constructed in stainless steel and therefore is compatible with most materials used
in a heating system.
If a cleaning agent and inhibitor are used, they must be applied in accordance with their manufacturers instructions. Only
products from Fernox and Sentinel are acceptable for use with the Alpha CD boilers. Further information can be obtained from
Fernox (Tel: 0179 9521133) or Sentinel (Tel: 0151 4209563).
If the Cyclone is fitted in the heating return on the jig, the heating system should still be thoroughly flushed as detailed below.
The Cyclone collection point should be emptied via the drain point (see Fig. 13b) after flushing has been completed.
The system should be flushed in accordance with BS 7593 and BS 5449. The following procedures are recommended:
1. Installing onto a new system:a.Fill the system, vent at high points, at pump and radiators.
b.Check for leaks.
c.Rapidly drain the system.
d.If required, chemically clean the system as instructed by the recommended cleaner manufacturer.
Note: Ensure that the system is flushed to remove any remains of the cleaner.
e.If chemical cleaner is not used to clean the system:-
i) Refill the system.
ii) Switch on the boiler and allow the system to heat up to the normal operating temperature.
iii) Rapidly drain the system while the water is still hot.
iv) Refill the system.
f. As required, add the recommended inhibitor to the system as instructed by the inhibitor manufacturer.
g.Recheck for leaks.
2. Installing onto an existing system, clean the system before fitting the new boiler:a.If the old boiler is still working:-
i) Switch on the boiler and allow the system to heat up to the normal operating temperature.
ii) Rapidly drain the system while the water is still hot.
iii) Refill and chemically clean the system as instructed by the recommended cleaner manufacturer.
iv) Ensure the system is flushed to remove any remains of the cleaner.
v) Fit the new boiler.
b.If the old boiler is not working:-
i) Rapidly drain the system.
ii) Remove the old boiler.
iii) Flush the system through.
iv) Fit the new boiler.
v) Refill and chemically clean the system as instructed by the recommended cleaner manufacturer.
vi) Ensure the system is flushed to remove any remains of the cleaner.
c.As required, add the recommended inhibitor to the system as instructed by the inhibitor manufacturer.
d.Check for leaks.
3.10 DISPOSAL OF CONDENSATE
Provision must be made for the safe disposal of condensate produced by the flue gases of the Alpha CD boilers and reference
should be made to BS 6798: 2000 for the requirements on the disposal of condensate.
The boilers incorporate a condensate trap which has a seal of 75 mm, therefore no additional trap is required.
The condensate should ideally be discharged internally into an internal waste pipe (washing machine/sink waste) or soil pipe to
avoid the possible risk of freezing. The pipework must be in 22 mm pipe.
External pipe runs should be avoided, but if it is necessary, the pipework should be at least 32 mm and protected from the risk
of freezing with a waterproof insulation and the length should be kept to a maximum of 3 m. Termination should be into an
external gulley or soakaway as shown in Figs. 8 and 9.
Note: All pipework must have a continuous fall (see Figs. 8 and 9) from the boiler and must be of an acid resistant material
such as plastic waste pipe. (copper or steel is not suitable).
It should be noted that the connection of a condensate pipe to a drain may be subject to local building control requirements.
Alpha CD25X/28X - General Boiler Information
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Fig. 8 - External gully
22mm termination
from boiler
500 mm min.
100mm plastic tube
Cement mortar
sealing
O
2½ fall
25mm
Ground level (either/or)
300mm
Bottom of tube sealed
Soakaway depth 400mm
filled with limestone chippings
Two rows of 3 x 12mm
holes at 25mm centres,
50mm from the bottom
of the tube. Holes to face
away from house.
Fig. 9 - External soakaway
3.11 DOMESTIC HOT WATER SYSTEM
The minimum flow rate needed for the flow switch and burner to operate is 2.5 litres/min.
The incoming mains water pressure should be between 0.2 and 8 bar to ensure efficient operation. If the pressure is above 7 bar
a pressure reducing valve must be fitted.
To ensure economic use, the pipe runs between the boiler and taps should be in 15 mm copper pipe and be as short as
possible. Where possible the pipework should be insulated to reduce heat loss.
All taps and mixing valves used with the hot water system must be suitable for operating at a mains pressure of up to 8 bar.
Showers - A shower may be used with the boiler if required.
If a loose or flexible head type shower is used it may require the fitting of a double check valve, to comply with Water Bye Law 17.
Bidets - No anti-syphonage arrangements are necessary, provided the outlets are shrouded and it is not possible to attach a
temporary hand held spray. A supply of direct mains fed hot and cold water is permitted provided the appliance is of the overrim flushing type.
Before the mains water supply pipe is connected to the boiler, it should be thoroughly flushed out to avoid the danger of dirt or
foreign matter entering the boiler.
Alpha CD25X/28X - General Boiler Information
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