Alpha CD25X, CD28X Installation and Servicing Instructions

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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		Alpha CD28X	G.C. No. 47 532 37

For use with Natural Gas only

Leave these instructions with the User

CONTENTS


1	.......................................Introduction	2	8	...................Component replacement	25
2	Technical data ...................................	3	9	Wiring diagrams ................................	31
3	General boiler information ..................	7	10	Fault finding ......................................	33
4	Installation .........................................	13	11	Short parts list ...................................	37
5	Commissioning .................................	19	12	Benchmark Checklist ........................	38
6	Boiler operation .................................	22	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.

2	Alpha CD25X/28X - Contents/Introduction

2TECHNICAL DATA

2.1PERFORMANCE - NATURAL GAS (CAT: I2H 2H - G20 - 20 mbar)

Alpha CD25X

Central Heating			MAX.	MIN.
Heat Input (Hs)		kW	20.4	5.2
(Gross)		Btu/h	69 600	17 740
Heat Input (Hi)		kW	18.4	4.7
(Net)		Btu/h	62 780	16 040
Heat Output (Hs condensing)		kW	19.5	4.8
(50°C/30°C)		Btu/h	66 530	16 400
Heat Output (Hi non-condensing) kW			18.0	4.5
(80°C/60°C)		Btu/h	61 420	15 350

Differential Burner	Room sealed	mbar	3.32	0.4
	chamber panel
Pressure	chamber panel	in wg	1.33	0.16
Pressure	fitted	in wg	1.33	0.16

Gas Rate		m³/h	1.95	0.6

		ft³/h	68.8	21.2

Alpha CD25X

Domestic Hot Water			MAX.	MIN.
Heat Input (Hs)		kW	26.6	5.2
(Gross)		Btu/h	90 760	17 740
Heat Input (Hi)		kW	24.0	4.7
(Net)		Btu/h	81 900	16 040
Output to Water (Hs)		kW	24.0	4.5
(modulating)		Btu/h	81 900	15 350
Differential Burner	Room sealed	mbar	5.20	0.4
Pressure	chamber panel	in wg
	chamber panel		2.08	0.16
	fitted		2.08	0.16
Gas Rate		m³/h	2.54	0.6
		ft³/h
		ft³/h	89.7	21.2
Flow Rate at 35°C Rise		L/min	9.6
		gal/min
		gal/min	2.2

Specific Flow Rate (D) at 30°C Rise		L/min	11.2
(Flow rate @ 30K to EN625)		gal/min	2.5

Alpha CD28X

Central Heating			MAX.	MIN.
Heat Input (Hs)		kW	27.3	5.5
(Gross)		Btu/h	93 150	18 760
Heat Input (Hi)		kW	24.6	5.0
(Net)		Btu/h	83 930	17 060

Heat Output (Hs condensing)		kW	25.8	5.1
(50°C/30°C)		Btu/h	88 030	17 400
Heat Output (Hi non-condensing) kW			24.0	4.9
(80°C/60°C)		Btu/h	81 900	16 720

Differential Burner	Room sealed	mbar	6.6	0.24
	chamber panel
Pressure	chamber panel	in wg	2.64	0.10
Pressure	fitted	in wg	2.64	0.10

Gas Rate		m³/h	2.61	0.53

		ft³/h	92.1	18.7

Note: The above appliances are fully modulating and are not range rated.

Alpha CD28X

Domestic Hot Water			MAX.	MIN.
Heat Input (Hs)		kW	31.8	5.5
(Gross)		Btu/h	108 500	18 760
Heat Input (Hi)		kW	28.7	5.0
(Net)		Btu/h	97 900	17 060

Output to Water (Hs)		kW	28.7	4.9
(modulating)		Btu/h	97 900	16 720

Differential Burner	Room sealed	mbar	8.83	0.24
Pressure	chamber panel	in wg
	chamber panel		3.53	0.10
	fitted		3.53	0.10

Gas Rate		m³/h	3.03	0.53
		ft³/h
		ft³/h	106.9	18.7

Flow Rate at 35°C Rise		L/min	11.4
		gal/min
		gal/min	2.5

Specific Flow Rate (D) at 30°C Rise		L/min	13.3
(Flow rate @ 30K to EN625)		gal/min	2.9

Alpha CD25X/28X - Technical Data

2.2 SYSTEM

Central Heating (Sealed System)

Max. Working System Pressure	2.5 bar
Min. System Pressure	0.5 bar

Max. System temperature	82°C

Pressure Relief Valve Setting	3 bar (44 PSI)

Expansion Vessel Size (pre-charge press.)	8 L at 0.8 bar

Flow Connection	22 mm

Return Connection	22 mm
Relief Valve Connection	15 mm
Recommended System Pressure (cold)	1.0 bar

CH Water Temp. (Approx. max.)	82°C (180°F)

2.3COMPONENTS

Burner		Stainless steel

Main Heat exchanger		Stainless steel
DHW Heat Exchanger		Stainless Steel

Main Burner Injector	CD25X	5.2 mm

	CD28X	5.4 mm

Flue - Outer Duct		White
Flue - Inner Duct		Plastic

Domestic Hot Water

Max. Mains Inlet Water Pressure		8 bar

Min. Mains Water Pressure		0.2 bar

Min. DHW Flow Rate		2.5 l/min

Mains Inlet Connection		15 mm
DHW Outlet Connection		15 mm

DHW Water Content	CD25X	0.2 L

	CD28X	0.26 L

Outlet Water Temp. (Approx. max.)		62°C (144°F)

Flow Regulator Fitted	CD25X	10 l/min
	CD28X	12 l/min

2.4 ELECTRICAL

Supply	230/240 V ~ 50 Hz

External Fuse	3 A
Power Consumption	120 W
Internal Fuse - Main Terminal	F2 A

PCB Fuse F1	315 mAT

PCB Fuse F2 and F3	2.5 AF

Electrode Spark Gap	3 - 4 mm

Electrical Enclosure Degree of Moisture Protection	IPX4D

2.5 INSTALLATION

Min. Clearances for Servicing	Top	235 mm

(from casing)	Bottom	250 mm

	Sides	5 mm
	Front	450 mm
Flue Terminal Size		100 mm Dia.
Flue Terminal Protruding		100 mm

Hole Size Required For Flue Assy.		110 mm Dia.

Lift Weight	CD25X	41 kg

	CD28X	42 kg

2.6 GENERAL

Case Dimensions	Height	720 mm
	Width	440 mm
	Depth	300 mm

	Depth (with Jig)	340 mm

Gas Connection		22 mm

Primary Water Content	CD25X	2.5 L

	CD28X	2.8 L

Air Duct Diameter		100 mm

Flue Duct Diameter		60 mm

2.7PERFORMANCE DATA

	%CO2 content (± 0.2%)			Sedbuk rating
Boiler model		Natural Gas		Efficiency	SAP efficiency	NOx class

	Min	CH Max	DHW max	band	(%)

CD25X	9.0	9.4	9.4	A	90.1	5
CD28X	8.9	9.4	9.4	A	90.0	5

4	Alpha CD25X/28X - Technical Data

2.8FLUE 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.

2.9AVAILABLE PUMP HEAD FOR CENTRAL HEATING

Output (50/30°C)		Available pump head			Flow rate

kW	Btu/h		20°C		20°C

		metres		feet	litre/min	gal/min

25.40	86 700	2.3		7.6	16.6	3.7

18.70	64 000	3.5		11.6	12.6	2.8

15.60	53 000	3.8		12.6	10.5	2.3

12.35	42 200	4.0		13.2	8.3	1.8

5.30	18 100	4.6		15.2	3.2	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.

Not	Red	Red	Brown	Blue
Used	Wire	Wire	Wire	Wire

5	4	3	2	1
	Internal Clock Terminals

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

Alpha CD25X, CD28X Installation and Servicing Instructions

2.11 BOILER SCHEMATIC

1	9	23	11	5
12		- +
		- +		13
34
8				20
7				21
				21
			-	14
31
		+		32
10				30
				33
6
				15
19
				16

														17




		4												18



		3
		3
		35												27
														27
		2
		29												28
							22							26



		24
						25



								Domestic
			Gas					Domestic			Primary
								hot water			Heating
				Condensate					outlet		Heating
				Condensate					outlet		return	Primary
					discharge						return	Primary
					discharge					Cold mains		Heating
										Cold mains		Heating
										water inlet		flow
1	-	Heat exchanger thermal fuse				13	-	Overheat thermostat				25	- Mains inlet on/off valve
2	-	DHW flow switch, filter and flow regulator				14	-	Expansion vessel				26	- On/off valve (2 off)
3	-	Diverter valve				15	-	Automatic air vent				27	-	Automatic by-pass
4	-	Gas valve				16	-	Pump				28	- Cyclone separator (if applicable)
5	-	Primary temperature sensor				17	-	Drain point				29	-	Condensate trap
6	-	DHW heat exchanger				18	-	Pressure relief valve				30	-	Injector
7	-	Main burner				19	-	Primary pressure switch				31 -		Venturi
8	-	Primary/condensing heat exchanger				20	-	Ignition electrodes				32	-	Venturi negative point
9	-	Room sealed chamber				21	-	Flame sensing electrode				33	-	Venturi positive point
10 -		Fan				22 -		DHW temperature sensor				34 -		Flue temperature sensor
11 -		Pressure differential test points				23	-	Flue sampling point				35	-	Diverter valve motor
12 -		Flue hood				24	-	Gas service cock

Fig. 2

6	Alpha CD25X/28X - Technical Data

3GENERAL BOILER INFORMATION

3.1GAS 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.

3.2ELECTRICAL 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.

3.3AIR 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.

3.4FLUE 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)

For side exit flue (including terminal)

L = B + 140 mm (180 mm if wall jig is used)

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

HORIZONTAL FLUE OPTIONS - Lmax = 12 metres

L = B + C + 225 mm

L = B + E + F + 225 mm + (90° bend = 1.3 metre) (add 40 mm to 'F' if a jig is used)

VERTICAL FLUE OPTIONS

L = B + C + E + 225 mm

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
	H
H

Not less than 300 mm

Hmax = 15 m

Hmax = 13.2 m

Fig. 3

8	Alpha CD25X/28X - General Boiler Information

3.5FLUE TERMINAL LOCATION - Fig. 4

O P G

Boundary

H I

	Terminal position	Min. distance (mm)

A	Directly below an opening, air brick, windows, etc.	300 (See Note 1)

B	Below gutters, soil pipes or drain pipes	75 (See Note 3)

C	Below eaves	200 (See Note 3)

D	Below balconies	200 (See Note 3)

E	From a vertical drain pipe or soil pipe	150 (See Note 3)
F	From an internal or external corner	300 (See Note 2)

G	Above ground, roof or balcony level	300

H	From a surface or boundary facing the terminal	600 (See Note 4)

I	From a terminal facing the terminal	1200 mm

J	Above an opening, air brick, window etc.	300 (See Note 1)
K	Vertically from a terminal on the same wall	1500 mm

L	Horizontally from a terminal on the same wall	300 mm

M	Horizontally from an opening, air brick, window etc.	300 mm (See Note 1)

N	Minimum protrusion through a roof	300 mm

O	From a vertical obstruction	300 mm
P	From an openable window	600 mm
Q	From an adjacent vertical terminal	600 mm

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.

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.

3.6BOILER 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

3.7CENTRAL 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

Boiler casing

Heating flow

Heating return

System Note: A drain tap should be installed at the lowest drain tap point of the heating circuit and beneath the appliance.

Static head of system

Automatic air vent

Additional expansion vessel (if required)

Double check valve assy.

Filling point

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.

Fig. 5

3.8FILLING 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.

					Overflow
Hose
unions	Double check				Double check
Heating circuit	valve assembly		Mains		Double check
Heating circuit					valve assembly
return				Heating circuit
			water
			water
Stop		Stop	supply	return
valve		valve			Stop
					Stop

	Test cock	valve
Filling loop		Test cock
Filling loop
temporarily connected

Mains water supply

Feed cistern to be located above highest point in the system

Fig. 6

Fig. 7

10 Alpha CD25X/28X - General Boiler Information

3.9FLUSHING 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 11

Fig. 8 - External gully

22mm termination

from boiler Cement mortar sealing

500 mm min.

Ground level (either/or)

2½O fall

25mm

100mm plastic tube

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.

12	Alpha CD25X/28X - General Boiler Information

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