Please leave these instructions with the user

Baxi Combi 80Eco

Gas Fired Wall Mounted Combination Boiler

Installation and

Servicing Instructions

Natural Gas

Baxi Combi 80Eco

G.C.N

o 47 075 05

Baxi UK Limited is one of the leading manufacturers of domestic heating products in the UK.

Our first priority is to give a high quality service to our customers. Quality is designed into every Baxi product

- products which fulfil the demands and needs of customers, offering choice, efficiency and reliability.

To keep ahead of changing trends, we have made a commitment to develop new ideas using the latest technology - with the aim of continuing to make the products that customers want to buy.

Everyone who works at Baxi has a commitment to quality because we know that satisfied customers mean continued success.

We hope you get a satisfactory service from Baxi. If not, please let us know.

The boiler meets the requirements of Statutory Instrument

“ The Boiler (Efficiency) Regulations 1993 N o 3083” and is deemed to meet the requirements of Directive 92/42/EEC on the energy efficiency requirements for new hot water boilers fired with liquid or gaseous fuels:-

Type test for purpose of Regulation 5 certified by:

Notified Body 0051.

Product/Production certified by:

Notified Body 0051.

For GB/IE only.

2

Baxi is a BS-EN ISO 9001

Accredited Company

Contents

Section

1.0

Introduction

2.0

General Layout

3.0

Appliance Operation

4.0

Technical Data

5.0

Dimensions and Fixings

6.0

System Details

7.0

Site Requirements

8.0

Installation

9.0

Commissioning the Boiler

10.0 Completion

11.0 Servicing the Boiler

12.0 Changing Components

13.0 Illustrated Wiring Diagram

14.0 Fault Finding

15.0 Short Parts List

37

42

27

36

24

25

17

22

9

12

7

8

Page

4

5

6

3

4

Control Box

Fig. 1

Case Front Panel

Data Badge

NOTE: This appliance must be installed in accordance with the manufacturer’s instructions and the regulations in force. Read the instructions fully before installing or using the appliance.

“Benchmark” Log Book

As part of the industry-wide “Benchmark” initiative all Baxi boilers now include an Installation, Commissioning and Service Record Log Book.

Please read the Log Book carefully and complete all sections relevant to the appliance and installation. These include sections on the type of controls employed, flushing the system, burner operating pressure etc.

The details of the Log Book will be required in the event of any warranty work. Also, there is a section to be completed at each subsequent regular service visit. The Log Book must be left with the user.

1.0 Introduction

Baxi UK Limited declare that no substances harmful to health are contained in the appliance or used during appliance manufacture.

1.1

Description

1. The Baxi Combi 80Eco is a fully automatic gas fired wall mounted combination boiler. It is room sealed and fan assisted, and will serve central heating and mains fed domestic hot water.

2. The boiler is set to give a maximum output of

24.0 kW.

3. It is designed for use on Natural Gas (G20) and can be converted to use Propane or Butane.

4. The boiler is suitable for use only on fully pumped sealed heating systems. Priority is given to domestic hot water.

5. The boiler data badge gives details of the model, serial number and Gas Council number and is situated on the control box. It is visible when the case front panel is removed (Fig. 1).

6. The boiler is intended to be installed in residential

/ commercial / light industrial E.M.C. environments on a governed meter supply only.

7. The boiler must be installed with one of the purpose designed flues such as the standard horizontal flue kit, part no. 247719.

8. All systems must be thoroughly flushed and

treated with inhibitor (see section 6.2).

1.2

Installation

1. The appliance is suitable for installation only in G.B. and I.E.

and should be installed in accordance with the rules in force.

For Ireland install in accordance with I.S.813 “I

NSTALLATION OF

G

AS

A

PPLIANCES

”. The installation must be carried out by a

CORGI Registered Installer or other competent person and be in accordance with the relevant requirements of G

AS

S

AFETY

(Installation and Use) R

EGULATIONS

, the B

UILDING

R

EGULATIONS

(Scotland) (Consolidation), the L

OCAL

B

UILDING

R

EGULATIONS

, the C

URRENT

I.E.E. W

IRING

R

EGULATIONS and the bye laws of the

Local Water Undertaking. Where no specific instructions are given, reference should be made to the relevant BRITISH

STANDARD CODES OF PRACTICE.

1.3

Optional Extras

Various flue extensions, bends, vertical flue kits, control accessories etc. are available as optional extras. These are detailed in a separate publication.

19

18

17

16

15

14

13

12

11

10

9

8

7

Fig. 2

3

4

5

6

1

2

2.0 General Layout

2.1

Layout

13.

14.

15.

16.

9.

10.

11.

12.

5.

6.

7.

8.

1.

2.

3.

4.

21.

22.

23.

24.

25.

17.

18.

19.

20.

Air Pressure Switch

Expansion Vessel

Burner Manifold

Automatic Air Vent

DHW Plate Heat Exchanger

Circulation Pump

Drain Off Point

Pressure Relief Valve

Optional Integral Timer Position

Central Heating System Pressure Gauge

Control PCB

Control Box

3-Way Valve Assembly

Spark Generator

Flame Sensing Electrode

Spark Electrode

Burner

Primary Heat Exchanger

Fan Assembly

On / Off / Reset Selector Switch

Burner On Neon

Power On Neon

Flame Failure Neon

Central Heating Temperature Control

Hot Water Temperature Control

20 21 22 23 24 25

2

1

0 bar

4

3

10 9

Fig. 3

5

3.0 Appliance Operation

1

Central Heating Circuit

2

NOTE: All delay timers mentioned in 3.1 and

3.2 are overridden by domestic hot water demand.

3.1

Central Heating Mode

(Fig. 4)

3 4

23

22

21

25

24

26

17

9

8

10

11

7

5 6

1. With a demand for heating, the pump circulates water through the primary circuit. At a predetermined flow rate the central heating flow switch operates, initiating the ignition sequence.

2. The main burner ignites at low rate, then the gas valve controls the gas rate to maintain the heating temperature measured by the temperature sensor.

3. When the flow temperature exceeds the setting temperature, a 3 minute delay occurs before the burner relights automatically (anti-cycling). The pump continues to run during this period.

Fig. 4 16

20

19

18

15 14 13 12

3.2

Domestic Hot Water Mode

(Fig. 5)

Key

1 Primary Heat Exchanger

2 Burner

3 Ignition Electrode

4 Flame Sensing Electrode

5 Gas Valve

6 Pump

7 Automatic Air Vent

8 Plate Heat Exchanger

9 Flow Sensor with Filter

10 Pressure Relief Valve

11 Boiler Drain Point

12 Heating Return

13 Cold Water Inlet On/Off Valve and Filter

14 Gas Inlet

15 Domestic Hot Water Outlet

16 Heating Flow

17 Pressure Gauge

18 Hydraulic Differential Pressure Sensor Microswitch

19 Automatic By-Pass

20 Hydraulic Differential Pressure Sensor

21 Diverter Valve Assembly

22 Domestic Hot Water Flow Priority Assembly

23 Domestic Hot Water Flow Priority Microswitch

24 Temperature Sensor

25 Overheat Thermostat

26 Expansion Vessel

1. Priority is given to the domestic hot water supply. A demand at a tap or shower will override any central heating requirement.

2. The flow of water will operate the DHW flow switch which requests the 3 way valve to change position. This will allow the pump to circulate the primary water through the DHW plate heat exchanger.

3. The burner will light automatically and the temperature of the domestic hot water is controlled by the temperature sensor.

Domestic Hot Water Circuit

26

3 4

1

2

7

4. When the domestic hot water demand ceases the burner will extinguish and the diverter valve will remain in the domestic hot water mode, unless there is a demand for central heating.

IMPORTANT: When the selector switch is in the ‘0’ (Off) position the electrical supply to the boiler is isolated. The boiler will not operate and the integral timer (if fitted) will require resetting once the selector switch is turned to either the DHW or CH position.

5 6

Fig. 5

25

24

23

22

21 17

16

20

19

18

15 14

8

9

10

11

13 12

6

4.0 Technical Data

Appliance Type C

12

C

32

Appliance Category CAT II

2H 3+

Heat Input C/H & DHW (Gross)

Max Min kW

Btu/h

26.3

89,739

10.6

36,167

Heat Output Max kW 24.0

Btu/h

Min

9.3

81,891 31,732

Max Gas Rate (Natural Gas - G20)

(After 10 Mins) m ft 3

3 /h

/h

2.78

98.12

Burner Pressure (Natural Gas - G20)

Max Rate Min Rate mbar 12.2 ± 0.5

2.5 ± 0.2

in wg 4.88 ± 0.2

1.0 ± 0.2

Inlet Pressure (Natural Gas - G20) mbar 20 in wg 8

Burner Injector (Natural Gas - G20)

12 x 1.28mm Diameter

Electrical Supply 230V~ 50Hz

(Appliance must be connected to an earthed supply)

Power Consumption 170W

External Fuse Rating 3A

Internal Fuse Rating

Fuse 2A Fast Blow to BS 4265

Electrical Protection

IPX4D

SEDBUK Declaration For Combi 80Eco

The seasonal efficiency (SEDBUK) is 78.6%

This value is used in the UK Government’s Standard

Assessment Procedure (SAP) for energy rating of dwellings.

The test data from which it has been calculated have been certified by 0051.

LPG Gases - Propane G31 Butane G31

Burner Injector 12 x 0.77mm diameter

Burner Pressure

Propane mbar

Max Rate

36.2

Butane in wg mbar in wg

14.5

28.3

11.3

Min Rate

6.4

2.6

5.3

2.1

Inlet Pressures mbar in wg

Butane

28

11.2

Propane

37

14.8

NOx Class

Flue Terminal

Dimensions

3

Diameter 100mm

Projection 95mm

Connections

Gas Supply

Central Heating Flow

Central Heating Return

Cold Water Mains Inlet

-

copper tails

22mm

22mm

22mm

15mm

DHW Flow 15mm

Pressure Relief Discharge 15mm

Outercase Dimensions

Casing Height

Overall Height Inc Flue

Elbow

Casing Width

Casing Depth

780mm

980mm

450mm

345mm

Clearances

Both Sides

Above Casing

Below Casing

Front

Front

5 mm Min

200 mm Min

200 mm Min

450 mm Min (For Servicing)

5 mm Min (In Operation)

Weights

Packaged Boiler Carton

Packaged Flue Kit

Installation Lift Weight kg

46

3

38.5

Central Heating Primary Circuit

Pressures

Safety Discharge

Max Operating

Min Operating

Recommend Operating bar

3

2.5

0.5

1-2

DHW Circuit

Pressures

Max Operating

Min Operating

Min Operating Pressure at 9.8 l/min

Flow Rates

DHW Flow Rate

@ 30 o C Rise

DHW Flow Rate

@ 35 o C Rise

Min Working

DHW Flow Rate bar

8

0.2

0.9

l/min

11.4

9.8

2.5

Pump

Available Head See graph below

Expansion Vessel - (For Central Heating only. Integral with appliance) bar

Min Pre-charge Pressure 0.5

litre

Max Capacity of

CH System

Primary Water Content

125 of Boiler (unpressurised) 1.0

Temperatures

C.H. Flow Temp

(adjustable)

35°C to 85°C max

(± 5°C)

D.H.W. Flow Temp

(adjustable)

35°C to 65°C max

(± 5°C) dependent upon flow rate

4

3.5

3

2.5

2

1.5

1

0.5

0 l/h 0

Pump - Available Head

200 400 600 800 1000 1200

7

5.0 Dimensions and Fixings

Fig. 6

D

B

360° Orientation

C

G

E

A

Tube Ø 100mm

F

Dimensions

A 780mm

B 345mm

C 450mm

D 107mm Ø Min.

E 200mm

F 190mm

G 143mm

8

95mm

Heating

Flow

65mm

Domestic Hot

Water Outlet

65mm

Gas Inlet

65mm

Cold Water

Inlet

65mm

Heating

Return

Left Hand Side of Boiler

View from under the appliance

165.7mm

130mm

Wall

Fig. 7

6.0 System Details

6.1

Information

1. The Baxi Combi 80Eco Combination Boiler is a

‘Water Byelaws Scheme - Approved Product’.

To comply with the Water Byelaws your attention is drawn to the following installation requirements and notes (IRN).

a) IRN 001 See text of entry for installation requirements and notes.

b) IRN 302 Byelaw 14.

2. Reference to the WRC publications, ‘Water fittings and materials directory’ and ‘Water supply byelaws guide’ give full details of byelaws and the IRNs.

6.2

Central Heating Circuit

1. The appliance is suitable for fully pumped

SEALED SYSTEMS ONLY.

Treatment of Water Circulating Systems

• All recirculatory water systems will be subject to corrosion unless an appropriate water treatment is applied. This means that the efficiency of the system will deteriorate as corrosion sludge accumulates within the system, risking damage to pump and valves, boiler noise and circulation problems.

• For optimum performance after installation this boiler and its associated central heating system must be flushed in accordance with the guidelines given in BS 7593 “Treatment of water in domestic hot water central heating systems”.

• This must involve the use of a proprietary cleanser, such as BetzDearborn Sentinel X300 or

X400, or Fernox Superfloc. Full instructions are supplied with the products, but for immediate information please contact BetzDearborn (0151

420 9563) or Fernox (01799 550 811) directly.

• For long term protection against corrosion and scale, after flushing it is recommended that an inhibitor such as BetzDearborn Sentinel X100, or

Fernox MB-1 or Copal is dosed in accordance with the guidelines given in BS 7593.

Failure to flush and add inhibitor to the system may invalidate the appliance warranty.

• It is important to check the inhibitor concentration after installation, system modification and at every service in accordance with the manufacturer’s instructions. (Test kits are available from inhibitor stockists.)

• For information or advice regarding any of the above contact the Baxi Helpline.

6.3

Bypass

1. The boiler is fitted with an automatic integral bypass.

6.4

System Control

1. The boiler is designed for use in a heating system that incorporates external controls, i.e. a minimum of a timer device.

2. Suitable timer kits are available as optional extras.

3. For optimum operating conditions and maximum economy the fitting of a programmable thermostat, such as one of the Baxi Combi 80Eco Controllers, is recommended.

9

10

Fig. 8

Pressure Relief Valve

Fig. 9

Stop

Valve

Double

Check

Valve

DHW

Mains

Inlet

Temporary

Hose

Discharge Pipe

Stop

Valve

CH

Return

Fig. 10

6.0 System Details

6.5

System Filling and Pressurising

1. A filling point connection on the central heating return pipework must be provided to facilitate initial filling and pressurising and also any subsequent water loss replacement/refilling.

2. There are connection points on the mains cold water inlet and central heating return isolating taps to which the optional filling loop kit (Part No.

248221) can be assembled.

3. The filling method adopted must be in accordance with the Water Supply (Water

Fittings) regulations and the Water Bylaws

(Scotland).

4. Your attention is drawn to: Paragraph 24 of

Schedule 2 Section 8 of the publication Water

Regulations Guide which gives recommendations and guidance on approved methods for filling sealed systems.

5. The sealed primary circuits may be filled or replenished by means of a temporary connection between the primary circuit and a supply pipe provided the arrangement in accordance with

Diagram R24.2a of the Water Regulations Guide.

6. The temporary hose must be completely removed at both ends after use.

6.6

Expansion Vessel

(Central Heating only)

1. The appliance expansion vessel is pre-charged to 0.5 bar. Therefore, the minimum cold fill pressure is 0.5 bar. The vessel is suitable for correct operation for system capacities up to 125 litres. For greater system capacities an additional expansion vessel must be fitted - refer to BS 7074

Pt 1.

6.7

Pressure Relief Valve (Fig. 9)

1. The pressure relief valve is set at 3 bar, therefore all pipework, fittings, etc. should be suitable for pressures in excess of 3 bar.

2. The pressure relief discharge pipe should be not less than 15mm dia, run continuously downward, and discharge outside the building, preferably over a drain (Fig. 10). It should be routed in such a manner that no hazard occurs to occupants or causes damage to wiring or electrical components. The end of the pipe should terminate facing down and towards the wall.

3. The discharge must not be above a window, entrance or other public access. Consideration must be given to the possibility that boiling water/steam could discharge from the pipe.

Other Tap

Outlets

Check

Valve

Pressure

Reducing Valve

Stop Tap

Expansion

Vessel

Boiler

To Hot

Taps

Fig. 11

6.0 System Details

6.8

Domestic Hot Water Circuit

1. All DHW circuits, connections, fittings, etc.

should be fully in accordance with relevant standards, the Water Supply (water fittings)

Regulations and the Water Bylaws (Scotland).

2. Your attention is drawn to:

Schedule 2, Section 6 of the publication Water

Regulations Guide which relates to backflow prevention.

3. A single check valve must be fitted as shown in

Fig. 11 to prevent backflow to the supply pipe and to ensure the efficient operation of the expansion vessel which is required to accommodate the thermal expansion of the water.

4. When the domestic water system includes any device which prevents water expanding back towards the supply (check valve, loose jumpered stopcock, water meter, water treatment device) then an expansion vessel must be fitted (eg.

Zilmet 160ml, R 1 /

2

15bar).

5. If the hot water expansion is not provided for, then high pressures can develop which may result in damage to fittings and devices on the system.

6. The boiler’s maximum working mains pressure is 8 bar, therefore all pipework, connections, fittings, etc. should be suitable for pressures in excess of 8 bar. A pressure reducing valve must be fitted for pressures in excess of 8 bar. The manufacturer of any outlet fittings, such as a shower valve, may require a lower maximum pressure. The pressure reduction must take account of all fittings connected to the DHW system.

6.9

Showers

1. If a shower control is supplied from the appliance it should be of the thermostatic or pressure balanced type. Thermostatic type shower valves provide the best comfort and guard against water at too high a temperature.

Existing controls may not be suitable - refer to the shower valve manufacturer.

6.10

Hard Water Areas

1. If the area of the installation is recognised as a

HARD WATER AREA then a suitable device should be fitted to treat the mains water supply to the boiler.

11

5mm Min

Fig. 12

450mm Min

For Servicing

Purposes

12

Fig. 13

5 mm Min

In Operation

450mm 5mm Min

200mm Min

780mm

200mm Min

7.0 Site Requirements

7.1

Information

1. The installation must be carried out by a CORGI

Registered Installer or other registered competent person and be in accordance with the relevant requirements of the current G AS S AFETY (Installation and Use) R EGULATIONS , the B UILDING R EGULATIONS

(Scotland)(Consolidation), the L

OCAL

B

UILDING

R EGULATIONS , the current I.E.E. W IRING R EGULATIONS and the bye laws of the L OCAL W ATER U NDERTAKING .

Where no specific instruction is given reference should be made to the relevant BRITISH

STANDARD CODES OF PRACTICE. For Ireland install in accordance with IS 813 “I NSTALLATION OF

G AS A PPLIANCES ”.

7.2

Standard

BS 6891

BS 5546

BS 5449 Part 1

BS 6798

BS 5440 Part 1

BS 5440 Part 2

BS 7074

BS 7593

B.S. Codes of Practice

Scope

Gas Installation.

Installation of hot water supplies for domestic purposes.

Forced circulation hot water systems.

Installation of gas fired hot water boilers.

Flues.

Ventilation.

Expansion vessels and ancillary equipment for sealed water systems.

Treatment of water in domestic hot water central heating systems.

WARNING - The addition of anything that may interfere with the normal operation of the appliance without the express written permission of Baxi UK Limited could invalidate the appliance warranty and infringe the G AS S AFETY

(Installation and Use) R EGULATIONS .

7.3

Clearances (Fig. 12 & 13)

1. A flat vertical area is required for the installation of the boiler.

2. These dimensions include the necessary clearances around the boiler for case removal, spanner access and air movement. Additional clearances may be required for the passage of pipes around local obstructions such as joists running parallel to the front face of the boiler.

7.4

Location

1. The boiler may be fitted to any suitable wall with the flue passing through an outside wall or roof and discharging to atmosphere in a position permitting satisfactory removal of combustion products and providing an adequate air supply. The boiler should be fitted within the building unless otherwise protected by a suitable enclosure i.e. garage or outhouse. (The boiler may be fitted inside a cupboard - see Section 7.5).

2. If the boiler is sited in an unheated enclosure then it is recommended to leave the ON/OFF/RESET

Selector Switch in the domestic hot water and central heating position to give frost protection.

3. If the boiler is fitted in a room containing a bath or shower reference must be made to the current

I.E.E. W IRING R EGULATIONS and B UILDING

R

EGULATIONS

. If the boiler is to be fitted into a building of timber frame construction then reference must be made to the current edition of Institute of

Gas Engineers Publication IGE/UP/7 (Gas

Installations in Timber Framed Housing).

Gas Service Cock

Fig. 14

7.0 Site Requirements

7.5

Ventilation of Compartments

1. Where the appliance is installed in a cupboard or compartment, no air vents are required.

2. BS 5440: Part 2 refers to room sealed appliances installed in compartments. The appliance will run sufficiently cool without ventilation.

7.6

Gas Supply

1. The gas installation should be in accordance with BS6891.

2. The connection to the appliance is a 22mm copper tail located at the rear of the gas service cock (Fig. 14).

3. Ensure that the pipework from the meter to the appliance is of adequate size. Do not use pipes of a smaller diameter than the boiler gas connection

(22mm).

7.7

Electrical Supply

1. External wiring must be correctly earthed, polarised and in accordance with current I.E.E.

W IRING R EGULATIONS .

2. The mains supply is 230V ~ 50Hz fused at 3A.

NOTE: The method of connection to the electricity supply must facilitate complete electrical isolation of the appliance.

Connection may be via a fused double-pole isolator with a contact separation of at least

3mm in all poles and servicing the boiler and system controls only.

13

14

7.0 Site Requirements

7.8

Flue

1. The flue terminal position must be in accordance with the current editions of B.S.

5440 Part 1, and either Part J of the Building

Regulations England and Wales or Part F of the Building Standards (Scotland)

Regulations as appropriate.

2. If the terminal discharges onto a pathway or passageway, check that combustion products will not cause a nuisance and that the terminal will not obstruct the passageway.

3. If a terminal is less than 2 metres above a balcony, above ground or above a flat roof to which people have access, then a suitable terminal guard must be provided.

D

J

K

G

L

M

E

A

G

B,C

N

G

F

A

D

F

Likely flue positions requiring a flue terminal guard

H,I

Fig. 16

Terminal Position with Minimum Distance (Fig. 16) (mm)

A Directly below an openable window, air vent or any other

B ventilation opening.

Below gutter, drain/soil pipe.

C Below eaves.

D Below a balcony/car port roof.

E From vertical drain pipes and soil pipes.

F From internal or external corners.

G Above adjacent ground or balcony level.

H From a surface facing a terminal.

I Facing a terminals.

J From opening (door/window) in carport into dwelling.

K Vertically from a terminal on the same wall.

L Horizontally from a terminal on the same wall.

1200

1200

1500

300

M Above an opening, air brick, opening window etc.

300

N Horizontally to an opening, air brick, opening window etc.

300

300

25

25

25

25

25

300

600

Terminal

Assembly

300 min

Top View Rear Flue

Property Boundary Line

Fig. 18

100mm

1m

Fig. 17

Flue Trim

Adhesive Seal

7.0 Site Requirements

7.9

Flue Dimensions

The standard horizontal flue kit allows for flue lengths between 100mm and 1metre from elbow to terminal (Fig. 17).

The maximum permissible equivalent flue length is: 5 metres.

NOTE: Each additional 45° of flue bend will account for an equivalent flue length of 0.5m.

eg. 45° = 0.5m, 90° = 2 x 45° = 1m etc.

7.10

Flue Terminal Trim

1. Once the flue is secure the trim can be fitted if required.

2. Remove the protective backing from the adhesive seal. Apply the seal to the rear of the trim flange (Fig. 18).

3. Locate the trim over the flue terminal and push it back to the wall to compress the seal (Fig. 19).

Fig. 19

7.11

Terminal Guard (Fig. 20)

1. When codes of practice dictate the use of terminal guards, they can be obtained from most

Plumbers’ and Builders’ Merchants.

2. There must be a clearance of at least 50mm between any part of the terminal and the guard.

3. When ordering a terminal guard, quote the appliance model number.

4. The flue terminal guard should be positioned centrally over the terminal and fixed as illustrated.

Fig. 20

15

16

Maximum Length = 4m inc. 2 x 45° bends

Horizontal

Flues

Vertical

Flues

(Twin Pipe)

Maximum Length = 14m inc. 4 x 45° bends

Vertical

Flues

Maximum Length = 2m inc. 2 x 90° bends

7.0 Site Requirements

7.12

Flue Options

1. The Baxi Combi 80Eco can be fitted with flue systems as illustrated.

2. The standard flue is suitable only for horizontal applications.

3. Maximum permissible equivalent flue lengths are:-

Horizontal

Vertical

Vertical (Twin Pipe)

5 metres

4 metres

15 metres

4. Any additional “in line” bends in the flue system must be taken into consideration.

Their equivalent lengths are:-

Concentric Pipes:

45° bend 0.5 metres

1.0 metres 90° bend

Twin Flue Pipe

45° bend

90° bend

0.25 metres

0.50 metres

The elbow supplied with the standard horizontal flue is not included in any equivalent length calculations

5. The illustrations opposite show examples of maximum equivalent lengths.

6. Full details of part numbers and descriptions of all optional flue components and kits can be found in the Baxi Gas Central Heating Boilers

Installers’ Guide.

7. Instructions for guidance and fitting are included in each kit where appropriate.

Fixing Template

107mm diameter minimum aperture for flue tube

Appliance Wall Plate

190mm

For Side Flue Exit

Appliance Outline

General area for electrical supply

Central Heating Flow

Domestic Hot Water Outlet

Gas Supply

Cold Water Inlet

Central Heating Return

Pressure Relief

Flushing Tube

Central Heating Return

Combi 80Eco

FIXING TEMPLATE

8.0 Installation

8.1

Initial Preparation

The gas supply, gas type and pressure must be checked for suitability before connection

(see Section 7.6).

1. After considering the site requirements

(see Section 7.0) position the fixing template on the wall ensuring it is level both horizontally and vertically.

2. Mark the position of the two most suitable fixing slots for the wall plate and boiler lower fixing holes. It is preferable to use the horizontal fixing slots. For side flue exit, mark as shown.

3. Mark the position of the centre of the flue hole

(rear exit). For side flue exit, mark as shown.

4. If required, mark the position of the gas and water pipes. Remove the template.

5. Cut the hole for the flue (minimum diameter

107mm).

6. Drill the wall as previously marked to accept the wall plugs supplied. Secure the wall plate using two of the fixing screws.

7. Using a spirit level ensure that the plate is level before finally tightening the screws.

Fig. 22

Fig. 21

8.2

Flushing

1. Insert a tube into the central heating flow or return pipe (Fig. 22).

2. Flush thoroughly (see System Details, Section

6.2).

8.3

Preparing The Boiler

1. Remove all packaging.

2. Stand the boiler on its base by using the rear lower edge as a pivot.

NOTE: A small amount of water may drain from the boiler in the upright position.

Baxi UK Limited declare that no substances harmful to health are contained in the appliance or used during construction of the appliance.

17

18

Securing Screw

Fig. 24

Pressure Relief Valve

Washer

Fig. 25

Discharge Pipe

Wall Plate

Fig. 23

Fig. 26

8.0 Installation

8.4

Fitting The Boiler

1. Lift the boiler using the lower edges. Engage the slots at the top rear of the boiler on the wall plate hooks (Fig. 23).

2. Ensure that the boiler is level and sits against the wall.

3. Take the two steel washers and remaining screws. Using the previously drilled and plugged holes, secure the bottom of the boiler to the wall

(Fig. 24).

4. Remove the elbows, valves and sealing washers from the packaging. The 3 / 4 in valve with internal filter must be fitted to the central heating return. The filter is visible through the branch connection of the valve.

5. Using the sealing washers provided connect the valves to the heating flow and return, and the cold water inlet.

6. Connect the elbows to the gas service cock and hot water outlet pipe, and then connect the elbows to the boiler. Connect the elbows with flared ends to the valves.

7. Ensure that the sealing washers are used on all connections. The rubber washers must be used on the gas connections.

8. The gas and water supplies, central heating flow and return and domestic hot water flow can now be connected.

8.5

Fitting the Pressure Relief

Discharge Pipe (Fig. 25)

1. Remove the discharge pipe from the kit.

2. Determine the routing of the discharge pipe in the vicinity of the boiler. Make up as much of the pipework as is practical, including the discharge pipe supplied.

3. The pipework must be at least 15mm diameter and run continuously downwards to a discharge point outside the building (Fig. 26). See section

6.7 for further details.

4. Utilising one of the sealing washers, connect the discharge pipe to the adaptor and tighten the nut.

5. Complete the discharge pipework and route it to the outside discharge point.

IMPORTANT: Make all soldered joints before connecting to the pressure relief valve.

Fig. 27

Wall Thickness

(X)

(X)

Wall Thickness

8.0 Installation

8.6

Fitting The Flue

HORIZONTAL FLUE

1. The standard flue is suitable for lengths

100mm minimum to 1m maximum (measured from the edge of the flue elbow outlet).

Rear Flue: maximum wall thickness - 900mm

Side Flue: maximum wall thickness - 870mm

2. Locate the flue elbow on the adaptor at the top of the boiler. Set the elbow to the required orientation (rear, right or left).

3. Measure the distance from the outside wall face to the elbow (Fig. 27). This dimension will be known as ‘X’.

4. Taking the air duct, mark dimension ‘X’ as shown (Fig. 28). Measure the length of waste material, and transfer the dimension to the flue duct (Fig. 28).

5. Remove the waste from both ducts. Ensure that the cut ends are square and free from burrs.

6. Remove the flue elbow from the adaptor.

IMPORTANT: Check all measurements before cutting.

Fig. 28

(X)

Air Duct

Waste

Waste

Flue Duct

19

Elbow

Fig. 29

Seal

Adaptor

Clip

Screws

Seal

Fig. 30

Fig. 31

Clip

Restrictor

Flue Duct

Clamp

Flue Duct

8.0 Installation

8.6

Fitting the Flue (Cont)

IMPORTANT: If the equivalent flue length is greater than 1.5m the restrictor MUST be removed from the adaptor (Fig. 29).

7. Insert the flue duct into the air duct and pass them through the hole in the wall.

8. Take one of the rubber seals and position it on the boiler flue adaptor. Engage the flue elbow on the adaptor and pull the sleeve up so that it equally covers the joint (Fig. 29).

9. Remove the screws from one of the clips provided. Prise the clip apart and fit it over the seal. Set the elbow to the required angle (Fig.

30).

10. Refit the screws to the clip and tighten them to secure the elbow. Take the second rubber seal and position it on the flue elbow.

11. Locate the flue duct clamp on the flue outlet elbow. Draw the flue duct out of the air duct, engage it in the clamp and tighten the screws

(Fig. 31).

12. Draw the air duct out of the wall and align it with the elbow. Position the seal so that it equally covers the joint (Fig. 32).

13. Remove the screws from the second clip provided. Prise the clip apart and fit it over the seal. Refit the screws to the clip and tighten them (Fig. 32).

14. Where possible position the clips so that the screws are not visible.

15. Make good between the wall and air duct outside the building.

16. Fit the circular flue trim outside if required, and if necessary fit a terminal guard (see

Section 7.10 & 7.11).

VERTICAL FLUE

1. Only a flue approved with the Baxi Combi

80Eco can be used.

2. For information on vertical flues consult the

Baxi Installer Guide or Notes for Guidance supplied with the vertical flue pack.

Screws

Seal

Air Duct

20

Fig. 32

8.0 Installation

8.7

Making The Electrical Connections

Fig. 33

Fig. 34

Fuse

Fused supply 3A

230V ~ 50Hz

Live (brown)

Neutral (blue)

Earth (green/yellow)

230V 1

2

Always fit fast blow 2A fuse br b g/y bk bk

Fig. 36

Control Box Cover

Cable Clamp

Terminal Block

To connect the mains input cable proceed as follows:-

1. Slacken the facia securing screws and lift the outercase panel so that it’s securing tabs are clear of the facia. Remove the panel.

2. Remove the screws securing the facia panel and hinge it down (Fig. 35).

3. Remove the control box cover securing screws. Disengage the barbs on the control box from the cover. Remove the cover (Fig. 33).

4. Slacken the cable clamp on the LH side of the boiler chassis. Insert the cable through the clamp and route it to the terminal block (Fig. 34).

Fig. 35

Frost Thermostat

L

N

External Clock

N

Facia Panel

230 V

SL

L

N

1

2 br b g/y bk bk

5. Slacken the screws in the terminal block, connect the input cable, and tighten the screws.

6. If an external control is to be connected it can be done at this point. Run the input cable from the external control through the second cable clamp on the boiler chassis. Refer to the instructions supplied with the control.

7. Remove the link between terminal 1 and 2 and connect the wiring from the external control

(Figs. 36 & 37).

Room Thermostat

IMPORTANT: If an integral timer is fitted to the boiler an external frost thermostat wired as shown will not operate correctly. Only external timers may be used in such installations, as in the diagram.

Fig. 37

NOTE: If the room thermostat being used incorporates an anticpator it MUST be wired as shown in Fig. 37.

IMPORTANT: The external control MUST be suitable for 230V switching.

External

Controls

L

230 V

Fig. 38 bk b br bk b - blue br - brown bk - black r - red g - green w - white br

Selector /

Reset Switch

Key to Wiring

Functional Flow Diagram r b

PCB br bk r r r r b b

Pump br br bk b br

Fan b b

N

Pressure Switch

N

Safety Overheat Thermostat

NTC Sensor y g br w

Gas Valve br

Flame Sensing Electrode

Spark

Generator b r Spark Electrode

N

Hydraulic Differential Pressure Switch

3-way Valve Microswitch b N

8. Ensure that both mains input and, where fitted, external control input cables have sufficient slack to allow the control box to drop down. Tighten the cable clamp(s) on the boiler chassis.

9. If the optional integral timer is to be used it should be fitted at this point. Refer to the instructions supplied with the timer. NOTE: An external frost thermostat cannot be used with the integral timer.

8.8

Preliminary Electrical Checks

1. Prior to commissioning the boiler preliminary electrical system checks should be carried out.

2. These should be performed using a suitable meter, and include checks for Ground Continuity,

Resistance to Ground, Short Circuit and Polarity.

21

22

Selector Switch

9.0

Commissioning the Boiler

Pressure Gauge

2

3

1

0 bar

4

Fig. 39

Screw

Fig. 40

Automatic Air Vent

9.1

Commissioning the Boiler

1. Reference should be made to BS 5449 Section

5 when commissioning the boiler.

2. Open the mains water supply to the boiler.

3. Open all hot water taps to purge the DHW system.

4. Ensure that the filling loop is connected and open, then open the heating flow and return valves on the boiler.

5. Open the screw on the automatic air vent

(Fig. 40).

6. The system must be flushed in accordance with BS 7593 (see Section 6.2) and the flushing agent manufacturers instructions.

7. Pressurise the system to 1.0 bar then close and disconnect the filling loop (Fig. 39).

8. Turn the gas supply on and purge the system according to BS 6891.

9. Test for gas soundness.

10. If at any time during commissioning it is required to terminate a particular cycle, turn the selector to the OFF position and then back to either ( ) or ( ) (Fig. 41).

2 bar

Central Heating

Temperature Control

Hot Water

Temperature Control

Fig. 41

Selector Switch

Central Heating

Temperature Control

Pressure Test Point

Sealing Screw

Gas Valve

Minimum

Pressure

Screw

Fig. 43

Governor Cover Screw

Fig. 44

2 bar

Hot Water

Temperature Control

Fig. 42

9.0

Commissioning the Boiler

9.2

Checking the Burner Pressure

1. Turn on the gas and electrical supplies to the boiler and ensure that all external controls are calling for heat.

2. Set the hot water and central heating temperature controls to maximum and the selector switch to the OFF position (Fig. 42).

3. Slacken the pressure test point sealing screw on the gas valve and connect a pressure gauge (Fig.

43).

4. Disconnect the sensing tube from the gas valve.

5. Turn the selector switch fully anticlockwise against the spring pressure to the reset p[osition and hold for 2 seconds to reset the boiler.

6. Turn the selector switch to the Central Heating and Domestic Hot Water position ( ). The power ON light ( ) will illuminate (Fig. 42).

7. Turn on a hot water tap to give a flow rate of at least 10 l/min.

8. The pressure should be as quoted in Section 4.0

Technical Data. If not, check that the gas supply pressure is correct (Natural Gas 20mbar, Butane

30mbar and Propane 37mbar).

9. The burner pressure can be adjusted if required.

10. Remove the governor cover screw (Fig. 44) and adjust the pressure regulator screw until the maximum pressure is achieved.

11. Turn the boiler selector to the Off position and remove the plug from the NTC sensor.

12. Turn the boiler selector switch to the Central

Heating and Domestic Hot Water position ( ) and reconnect the plug to the NTC. Check and adjust as required the minimum pressure (Fig. 43).

This must be performed within 25 seconds after which the boiler resumes normal operation.

13. Disconnect the pressure gauge, tighten the pressure test screw and replace the sensing tube on the gas valve.

14. Replace the governor cover screw and set the selector switch to the position required.

23

24

Facia Panel

Case Front Panel

Fig. 45

10.0 Completion

10.1

Completion

1. Hinge the facia panel upwards and refit the case front panel. Secure them with the screws previously removed (Fig. 45).

2. Instruct the user in the operation of the boiler and system, explaining the operational sequence.

3. Carefully read and complete all sections of the

“Benchmark” Installation, Commissioning and

Service Record Log Book that are relevant to the appliance and installation. The details of the Log

Book will be required in the event of any warranty work. The Log Book must be handed to the user for safe keeping and each subsequent regular service visit recorded.

4. Hand over the Users Operating, Installation and Servicing Instructions and the Log Book, giving advice on the necessity of regular servicing.

Case Front Panel

Fig. 47

Facia Panel

Inner Door

Panel

Combustion

Box Door

Fig. 48

Fan Wires

Fan

Fig. 49

Sensing Tubes

Fig. 50

Outlet Sealing

Collar

11.0 Servicing the Boiler

11 .1

Annual Servicing

1. For reasons of safety and economy, it is recommended that the boiler is serviced annually.

Servicing must be performed by a competent person.

2. After servicing, complete the relevant section of the “Benchmark” Installation, Commissioning and Service Record Log Book. This should be in the possession of the user.

3. Ensure that the boiler is cool.

4. Ensure that both the gas and electrical supplies to the boiler are isolated.

5. Slacken the screws securing the facia panel.

Lift the outercase panel so that its securing tabs are clear of the facia. Remove the panel (Fig. 47).

6. Remove the screws securing the inner door panel. Lift the panel slightly to disengage it from the studs on top of the case (Fig. 48).

7. Note the positions of the two sensing tubes on the outlet elbow and three wires on the fan motor and remove them (Fig. 49).

8. Slacken the screws on the outlet sealing collar.

Ease the collar upwards as far as possible

(Fig. 50).

9. Remove the four screws securing the combustion box door and remove the door

(Fig. 48).

25

Baffle

Tab

Spring Clip 11.0

Servicing the Boiler

11.1

Annual Servicing (Cont)

Fig. 51

Fan and Hood

Assembly

Fig. 53

Electrode

Grommets

Fig. 52

10. Remove the spring clips retaining the air box side baffle plates. Disengage the tabs on the baffles from the slots in the fan hood (Fig. 52).

11. Undo the screws securing the fan hood assembly to the appliance back panel, and draw the fan and hood assembly forwards (Fig. 51).

12. Draw the burner out of the combustion box, pulling the electrode grommets from the slots in the combustion box lower panel (Fig. 53).

13. Disconnect the electrode leads and grommets from the electrodes. Completely remove the burner (Fig. 53).

14. Brush any deposits from the injectors. Do not use a pin or wire to clean them.

15. Brush the burner blades and venturis and clean the combustion box.

16. Ensure that the heat exchanger fins are clear of any obstruction.

D.H.W. Filters

17. If the flow of domestic hot water is diminished, it may be necessary to clean the filters.

Electrode

Leads

Fig. 55

Flow

Regulator

26

Cartridge

Body

Filter Gauze

Burner

Gas Supply Pipe

Threaded

Bush

Blanking

Cap

Fig. 53a

Fig. 56

18. Initially check the cold water inlet tap filter.

19. Turn the tap off. Undo the blanking cap and remove the threaded bush (Fig. 53a).

20. Extract the filter and rinse thoroughly in clean water. Reassemble and check the flow. If required clean the manifold filter as described below.

21. Undo the filter cartridge from the inlet/return manifold (Fig. 56).

Cold Water

Inlet Tap

22. Dismantle the cartridge and carefully remove the flow regulator and filter gauze. Rinse them thoroughly in clean water and reassemble in reverse order (Fig. 55).

23. Check that the pressure vessel charge is

0.5bar, reassemble in reverse order of dismantling and recommission.

24. Complete the relevant section of the

“Benchmark” Installation, Commissioning and

Service Record Log Book and hand it back to the user.

Inlet / Return Manifold

Venturi

Pressure

Switch

Fig. 57

Pressure

Switch Wires

Fan Wires

Fan and Hood

Assembly

Fig. 58

Fan

12.0 Changing Components

Sensing

Tubes

Sensing Tubes

Flue Outlet Elbow

Spring Clip

Baffle

Fig. 59

Outlet Sealing

Collar

IMPORTANT: When changing components ensure that both the gas and electrical supplies to the boiler are isolated before any work is started.

See Section 11.1 “Annual Servicing” for removal of case panel, door etc.

12.1

Pressure Switch

1. Note the positions of the two sensing tubes and three wires and remove them (Fig. 57).

2. Remove the two screws holding the pressure switch to the combustion box top panel.

3. Fit the new pressure switch and reassemble all components in reverse order of dismantling.

12.2

Fan

1. Note the positions of the two sensing tubes on the outlet elbow and three wires on the fan motor and remove them (Fig. 58).

2. Slacken the screws on the outlet sealing collar.

Ease the collar upwards as far as possible

(Fig. 59).

3. Remove the four screws securing the combustion box door and remove the door.

4. Remove the spring clips retaining the air box side baffle plates. Disengage the tabs on the baffles from the slots in the fan hood (Fig. 61).

5. Undo the screws securing the fan hood to the appliance back panel, and draw the fan and hood assembly forwards (Fig. 60).

6. Remove the screws and spring washers securing the fan to the hood. Transfer the flue outlet elbow to the new fan (Fig. 60).

7. Fit the new fan to the hood using the screws and spring washers previously removed.

8. Reassemble in reverse order of dismantling.

Tab

Fig. 61

Spring

Washer

Securing Screw

Fan Hood

Fig. 60

27

Fig. 62

Pipe Connecting Clips

Electrodes

Electrode

Grommets

Electrode

Leads

28

Burner

Fig. 63

Heat Exchanger

12.0 Changing Components

12.3

Heat Exchanger (Fig. 62)

1. Note the positions of the two sensing tubes on the outlet elbow and three wires on the fan motor and remove them (Figs. 58 to 61).

2. Slacken the screws on the outlet sealing collar.

Ease the collar upwards as far as possible.

3. Remove the four screws securing the combustion box door and remove the door.

4. Remove the spring clips retaining the air box side baffle plates. Disengage the tabs on the baffles from the slots in the fan hood.

5. Undo the screws securing the fan hood to the appliance back panel, and draw the fan and hood assembly forwards.

6. Drain the primary circuit. Prise the two pipe connecting clips off the joints in the flow and return pipes.

7. Lift the heat exchanger to disconnect the flow and return pipe joints. Withdraw it from the appliance, taking care not to damage the rear insulation piece.

8. Fit the new heat exchanger, ensuring that the tabs on the side insulation carriers engage in the slots in the heat exchanger side plates.

9. Reassemble in reverse order of dismantling, and repressurise the system.

12.4

Burner (Fig. 63)

1. Remove the four screws securing the combustion box door and remove the door.

2. Draw the burner out of the combustion box, pulling the electrode grommets from the slots in the combustion box lower panel.

3. Disconnect the electrode leads and grommets from the electrodes. Completely remove the burner.

4. Undo the screws securing the electrodes to the burner. Examine the condition of the electrodes, replacing if necessary. Fit the electrodes to the new burner.

5. Engage the burner location brackets over the studs on the injector manifold and reassemble in reverse order.

Fig. 64

Electrodes

Electrode

Grommets

Electrode

Leads

Side Insulation

Combustion

Box Door

Fig. 65

Injector

Manifold

Burner

Injector

Rear Insulation

Inlet Elbow

Gasket

12.0 Changing Components

12.5

Injectors (Fig. 64)

1. Remove the burner as described in Section

12.4.

2. Undo the screws securing the injector manifold to the inlet elbow and remove the manifold.

3. Unscrew and replace injectors as required and examine the sealing gasket, replacing as necessary. Reassemble in reverse order.

12.6

Electrodes (Fig. 64)

1. Remove the four screws securing the combustion box door and remove the door.

2. Draw the burner out of the combustion box, pulling the electrode grommets from the slots in the combustion box lower panel.

3. Disconnect the lead and grommet from the electrode being replaced. Undo the securing screw and withdraw the electrode to the burner.

4. Reassemble in reverse order.

12.7

Insulation (Fig. 65)

1. Remove the four screws securing the combustion box door and remove the door.

2. Slide the side insulation pieces carefully out of their carriers.

3. To replace the rear insulation piece it is necessary to remove the heat exchanger as described in Section 12.3 and slide out the side pieces.

4. The combustion box door insulation piece can be replaced by carefully bending up the two retaining tabs.

5. Replace all insulation pieces and reassemble in reverse order.

13.8

Front Insulation

Side Insulation

29

Fig. 67

Flow Pipe

Safety

Thermostat

Reset

Button

Temperature

Sensor

30

Fig. 66

Electrical

Plug

Earth Wire

Inlet Pipe

Gas Feed

Pipe

Gas Valve

12.0 Changing Components

12.8

Gas Valve (Fig. 66)

1. Undo the nut on the gas feed pipe at the tap rail under the boiler.

2. Remove the securing screws and hinge the facia panel down.

3. Disconnect the earth wire and pressure sensing pipe from the valve. Undo the screw securing the electrical plug to the valve and disconnect the plug.

4. Remove the screws securing the inlet pipe flange to the tap rail and those securing the outlet manifold to the burner manifold.

5. Remove the valve from the boiler.

6. Note the orientation of the inlet pipe and outlet manifold. Undo the securing screws and remove the pipe and manifold.

7. Examine the ‘O’ ring seals for damage, replacing as necessary.

8. Fit the inlet pipe and outlet manifold to the new valve, ensuring that the ‘O’ ring seals are in place.

9. Reassemble in reverse order and check the burner pressure (Section 9.2).

12.9

Temperature Sensor (Fig. 67)

1. Ease the retaining tab on the sensor away and disconnect the electrical plug.

2. Unscrew the sensor from it’s pocket and reassemble in reverse order. The plug will only fit one way.

12.10

Safety Thermostat / Reset (Fig. 67)

1. Pull the two electrical connections off the thermostat.

2. Remove the screws securing the thermostat to the mounting plate on the flow pipe.

3. Reassemble in reverse order. The thermostat is not polarised - either wire can fit either terminal on the thermostat.

Pump Wiring

Cover

Fig. 68

Socket Headed

Screw

Pump Body

Pump Head

Fig. 69

Pump Setting

Pump Wiring

Cover

Automatic

Air Vent

12.0 Changing Components

12.11

Pump - Head Only (Figs. 68 & 69)

1. Drain the primary circuit and remove the socket head screws securing the pump head to the body and draw the head away.

2. Undo the screw on the pump wiring cover and remove the cover. Using a suitable flat bladed screw driver press the cable securing levers downwards to release each wire after noting their position.

3. A standard Grundfos 15-50 replacement head can now be fitted. Connect the wiring to the new head. The pump speed must be set to 3.

4. Reassemble in reverse order.

12.12

Pump - Complete (Figs. 69 & 70)

1. Drain the primary circuit and unscrew the automatic air vent from the pump body. Undo the two screws securing the body to the pipe and manifold and draw the pump forwards.

2. Undo the screw on the pump wiring cover and remove the cover. Using a suitable flat bladed screw driver press the cable securing levers downwards to release each wire after noting their position.

3. Connect the wiring to the new pump. Examine the ‘O’ ring seals on the return pipe and manifold, replacing if necessary.

4. Fit the air vent to the pump body and reassemble in reverse order.

12.13

Automatic Air Vent (Fig. 70)

1. Drain the primary circuit and unscrew the automatic air vent from the pump body.

2. Examine the ‘O’ ring seal, replacing if necessary, and fit it to the new automatic air vent.

3. Reassemble in reverse order.

Fig. 70

31

Fig. 71

Boiler

Chassis

Lock Nut

Pressure Gauge

Capillary

Gauge Retaining

Bracket

Fig. 73

Fig. 74

Mounting Bracket

Pressure Gauge

Expansion Vessel

Vessel Outlet

Spigot

Spring

Washer

12.0 Changing Components

12.14

Pressure Gauge

1. Drain the primary circuit and undo the nut on the pressure gauge capillary (Fig. 71).

2. Remove the timer cover and ease the timer wiring aside. Undo the screws securing the gauge retaining bracket (Fig. 72).

3. Remove the bracket and gauge assembly.

Depress the barbs on the side of the gauge and remove the retaining bracket (Fig. 73).

4. Reassemble in reverse order.

Fig. 72

Timer Cover

12.15

Expansion Vessel

Fig. 75

1. To replace the expansion vessel it is necessary to remove the boiler from the wall.

NOTE: Alternatively a vessel of equivalent capacity can be fitted on the system return pipe as close as possible to the boiler.

2. Drain the system and undo all gas and water connections. Remove the flue elbow.

3. Lift the boiler off the wall bracket and lay it on it’s side on a clean flat surface.

Retaining Clip

4. Undo the nut on the vessel outlet spigot, and remove the locknut and spring washer securing the spigot to the boiler chassis (Fig. 74).

Upper Cross

Member

5. Undo the screws and remove the appliance upper cross member (Fig. 76). Slide the expansion vessel out of the retaining clips

(Fig. 75).

6. Reassemble in reverse order. Fully recommission the appliance and system.

Fig. 76

12.16

Spark Generator (Fig. 77)

1. Pull the electrode lead off the spark generator. Remove the screws and spring washers securing the generator to it’s mounting bracket.

2. Pull the rubber shroud off the generator input plug and disconnect the plug.

3. Reassemble in reverse order.

Spark Generator

Fig. 77

32

Electrode Lead

‘O’ ring seal

Fig. 78

Discharge Pipe

Grub Screw

Pressure Relief Valve

Fig. 79

Control Box Cover

P.C.B.

Selector

Switch

Fig. 80

Facia

Selector Switch Knob

Drive Pins

Temperature Control Knobs

12.0 Changing Components

12.17

Pressure Relief Valve (Fig. 78)

1. Drain the primary circuit.

2. Disconnect the discharge pipe from the valve.

Using a suitable hexagon key slacken the grub screw sufficiently to release the valve.

3. Note the orientation of the valve, rotate it and withdraw it from the manifold.

4. Fit the new valve and ‘O’ ring seal and set to the previously noted orientation. Reassemble in reverse order.

12.18

P.C.B.

1. Note the settings of the temperature control knobs. Rotate the knobs fully anticlockwise and carefully pull them off the drive pins (Fig. 80).

2. Remove the screws securing the control box cover and release the cover retaining barbs from their slots. Disengage the rear of the cover from the control box hinge pin (Fig. 79).

3. Note the position of all plugs and wires on the

P.C.B. and disconnect them. Pull the drive pins off the P.C.B.

4. Undo the securing screws and remove the

P.C.B.

5. Reassemble in reverse order, ensuring that the temperature controllers are reset to their previous positions (Fig. 80).

12.19

Selector Switch

1. Note the setting of the selector switch knob and carefully pull it off the facia (Fig. 80).

2. Remove the screws securing the control box cover and release the cover retaining barbs from their slots. Disengage the rear of the cover from the control box hinge pin (Fig. 79).

3. Note the position of the electrical connections and the orientation of the switch. Remove the electrical connections.

4. Remove the screws securing the switch to the facia panel (Fig. 80).

5. Fit the new switch, ensuring that it is correctly positioned and reassemble in reverse order.

33

Plate Heat Exchanger

Fig. 81

Rubber Seal

34

Sensing Pipes

Microswitch

Bracket

Manifold

Fig. 82

Diaphragm

Spring

Grub Screws

DHW Pressure

Differential Valve

Diaphragm

Pushrod

Plastic Disc

Fig. 83

12.0 Changing Components

12.20

Plate Heat Exchanger (Fig. 81)

1. Drain the primary circuit.

2. While supporting the heat exchanger undo the screws securing it to the brass manifolds.

3. Withdraw the heat exchanger upwards and to the left of the gas valve, taking care not to damage any wires or controls.

Seals

4. There are four rubber seals between the manifolds and heat exchanger which may need replacement.

5. Ease the seals out of the manifold. Replace carefully, ensuring that the seal is inserted into the manifold parallel and pushed fully in.

6. When fitting the new heat exchanger note that the left hand location stud is offset towards the centre more than the right hand one.

7. Reassemble in reverse order.

12.21

Diverter Valve Assembly (Fig. 82)

The diverter valve assembly comprises of a central heating pressure differential valve and a domestic hot water pressure differential valve.

These are connected to a manifold which is joined to the plate heat exchanger.

DHW Pressure Differential Valve (Fig. 83)

1. Drain the primary circuit.

2. Undo the screw securing the microswitch bracket to the valve (Fig. 82).

3. Disconnect the two sensing pipes and slacken the grub screws securing the valve to the diverter manifold.

4. Draw the valve away from the diverter manifold. The valve may now be replaced or split to examine the diaphragm.

5. To examine the diaphragm hold the valve body securely and carefully remove the six screws.

The diaphragm spring will force apart the two halves of the valve.

6. Remove the plastic disc and pushrod assembly. Carefully examine the diaphragm and replace it if there is any damage.

7. Reassemble in reverse order.

Heating

Flow Pipe

Fig. 84

Microswitch &

Bracket

Diaphragm

Fig. 85

Flow

Regulator

Diverter Manifold

Cartridge

Body

Filter Gauze

Central Heating

Pressure Differential

Valve

Sensing Pipe

Pressure Gauge

Capillary

Spring Clip

By-pass

Pipe

12.0 Changing Components

12.21

Diverter Valve Assembly (Cont)

Pressure Differential Valve (Fig. 84)

1. Remove the pressure differential valve as described above.

2. From the brass diverter manifold undo the nut on the heating flow pipe. Remove the screw securing the diverter manifold to the appliance lower bracket.

3. Disconnect the pressure gauge capillary from the diverter manifold and remove the two wires from the microswitch.

4. Prise off the spring clip securing the by-pass pipe to the diverter manifold and disconnect the sensing pipe.

5. Ease the diverter manifold out of the plate heat exchanger manifold. Remove the assembly from the appliance.

6. Undo the screw securing the microswitch bracket to the valve body. The sensor may now be dismantled to examine the diaphragm.

7. To examine the diaphragm hold the assembly securely and carefully remove the four screws.

The diaphragm spring will force the two halves of the valve apart.

8. Carefully examine the diaphragm and replace it if there is any damage.

9. Reassemble in reverse order.

CH Pressure Microswitch (Fig. 84)

1. Remove the two wires from the pressure microswitch.

2. Undo the screw securing the microswitch bracket to the valve body.

3. Reassemble in reverse order.

Inlet / Return Manifold

Fig. 86

12.22

Flow Regulator (Figs. 85 & 86)

1. Undo the filter cartridge from the inlet/return manifold.

2. Unscrew the venturi and remove the flow regulator.

3. Check the cleanliness of the filter gauze, rinsing thoroughly in clean water as necessary.

Fit the new flow regulator and reassemble in reverse order.

Venturi

35

13.0 Illustrated Wiring Diagram

Mains Input

Link g/y b br

1

2

3

4

Optional Timers

Gas Valve bk bk g/y

Fuse br b br bk bk b gr br y w b br

M3

8

9

10

17 bk

12

18 13

19

20

14

15

16

21

M1

11 br b b b br bk

22

23

24

25

26

M4 br r

Pump

Control PCB

3-Way Valve

Microswitch

M5 b br b br bk

FA2

On/Off/Reset

Selector Switch

Temperature Sensor

1

6

7

4

5

2

3

M2 r r b r r b

Hydraulic Differential

Pressure Switch

Safety Thermostat

Air Pressure

Switch

Fan

Flame

Sensing

Electrode

36

Igniter

br - brown bk - black b - blue r - red y - yellow g/y - green / yellow w - white gr - grey

14.0 Fault Finding

Carry out initial fault finding checks

1. Check that gas, water and electrical supplies are available at the boiler. Electrical supply = 230V ~ 50 Hz.

CH water system pressurised to 0.5 bar when the boiler is cold. The preferred minimum gas pressure is 19.5mbar (natural gas), 27mbar

(butane) or 36mbar (propane).

2. Carry out electrical system checks, i.e. Ground Continuity, Resistance to Ground, Short Circuit and Polarity with a suitable meter.

Note: These checks must be repeated after any servicing or fault finding.

3. Ensure all external controls are calling for heat and check all external and internal fuses. Before any servicing or replacement of parts ensure the gas and electrical supplies are isolated.

Refer to Section 13.0 “Illustrated Wiring Diagram” for position of numbered terminals

Central Heating - Follow operational sequence

Turn selector to neon illuminated

YES

NO

Go to section ‘A’

Turn thermostat to max.

Pump runs

YES

Primary flow switch operated

YES

NO

NO

Fan runs at max speed

YES

NO

Go to section ‘B’

YES

External controls and, where fitted, integral timer calling for heat

NO

Ensure controls are set to demand and verify the contacts are closed

Go to section ‘C’

Has safety thermostat been activated?

NO

Go to section ‘D’

YES

Press reset button on safety thermostat. If regular resetting is required, or appliance still does not operate, investigation is necessary

Air pressure switch proved

YES

Spark at ignition electrodes for up to 10 seconds

YES

NO

NO

Go to section ‘E’ illuminated

NO

Replace PCB

YES Turn selector to the reset position. If the light does not extinguish go to sections H & K

Burner on neon illuminated

NO

YES

Burner extinguishes after 10 seconds

NO

Burner output modulates until set temperature is reached

YES

NO

YES

Burner goes out

YES

Go to section ‘F’

Go to section ‘I’

Go to section ‘G’

Fan stops

YES

Pump stops

Go to section ‘J’

YES Operation sequence correct

37

14.0 Fault Finding

Domestic Hot Water - Follow operational sequence

Turn selector to neon illuminated

YES

NO

Go to section ‘A’

Is mains water filter and differential assembly clean?

YES

DHW flow rate more than

2.5l/min.

Turn thermostat to max. Open DHW tap fully.

DHW flow switch operated

YES

Primary water is diverted from CH system to DHW heat exchanger and flow microswitch operated

YES

NO

NO

NO

Pump runs

YES

Primary flow switch operated

YES

NO

NO

Fan runs at max speed

YES

Continuity across DHW flow microswitch terminals and PCB - M1 connector terminals 13 & 14

(terminals 12-14 open)

Go to section ‘B’

Go to section ‘C’

Has safety thermostat been activated?

NO

Go to section ‘D’

YES

NO

YES

YES

Replace diaphragm

YES

DHW flow valve diaphragm damaged

NO

DHW flow valve rod obstructed

Replace DHW flow microswitch

Replace PCB

Press reset button on safety thermostat. If regular resetting is required, or appliance still does not operate investigation is necessary

Go to section ‘J’

Air pressure switch proved

YES

Spark at ignition electrodes for up to 10 seconds

YES

NO

NO

Go to section ‘E’ neon illuminated

NO

Replace PCB

YES

Turn the selector to the reset position. If the light does not extinguish go to section H & K

Burner on neon illuminated

YES

Burner extinguishes after 10 seconds

NO

NO

YES

38

Burner output modulates to maintain temperature set at thermostat

YES

Close DHW tap

YES

DHW flow valve senses no flow.

Primary water diverted to

CH system. DHW flow switch released off

YES

Burner goes out

NO

NO

NO

Go to section ‘F’

Go to section ‘I’

Reduce the DHW flow rate. If burner does not modulate clean temperature sensor and

DHW heat exchanger. If modulation does not occur go to section ‘G’

Diverter valve spindle assembly faulty

Fan stops

YES

Pump stops

YES Operation sequence correct

Fault Finding Solutions Sections A to E

A

1.

2.

3.

Is there 230V at:

Main terminals L and N

YES

Main terminal fuse

NO

NO

Selector terminals a & b and a & 3. PCB - M1 connector terminals 9 & 10

Check electrical supply

Replace fuse

Check wiring

Replace selector

14.0 Fault Finding neon illuminated

NO

Replace PCB

B

Is there 230V at:

1.

2.

NO

Pump If pump jammed, release

NO

PCB - M1 connector terminals 8 & 15

YES

Change pump supply cable

Replace pump

Replace PCB

C

1.

2.

3.

CH system pressure 0.5 to 1.5 bar

NO

Check the tap of the automatic air vent is opened

NO

Primary flow valve diaphragm damaged

NO

YES

Re-pressurise system

Open the automatic air vent

Replace diaphragm

Flow valve rod obstructed

D

1.

Continuity across flow microswitch and PCB M2 connector terminals 3 & 4

NO

Replace microswitch

2.

Primary temperature sensor faulty.

Cold resistance approx. 11K ohms

(resistance reduces with increase in temp.)

YES

Replace sensor

3.

Fan connections correct at fan.

PCB - M5 connector, is 230V across terminals 28 & 29

NO

YES

Fan jammed or faulty winding

YES

Replace PCB

Replace fan

39

14.0 Fault Finding

E

Check and correct if necessary

1. Electrical and pressure tube connections

2. Blockage of pressure tubes

3. Restriction in flue

4. Venturi

NO

Replace air pressure switch

F

Gas at burner

NO

Ensure gas is on and purged

PCB - M4 connector is approx 70-140V DC, terminals 23 & 24

NO

YES neon illuminated

NO

Replace PCB

YES

Replace gas valve

Turn selector switch to reset position R

G

1.

Check the burner setting pressure of the gas valve

(see Section 9.2 of Commissioning)

2.

Voltage at main PCB - M4 connector is: approx 70 - 140V DC across terminals 23 & 24 approx 20 - 70V DC across terminals 21 & 22

Min burner pressure approx 14 mA DC across terminals 21 & 22

Max burner pressure approx 35 mA DC across terminals 21 & 22

YES

NO

Replace gas valve

Replace PCB

H

Check and correct if necessary

1. Ignition electrode and lead

2. Electrode connection

3. Spark gap and position

YES

230V at Main PCB - M4 connector across terminals

25 & 26 and at igniter.

Check wiring

NO

YES

Replace PCB

Replace igniter

40

14.0 Fault Finding

I

Ensure that mains input terminal L is Live (230V) and

N is Neutral (0V)

YES

Check and correct if necessary

1. Flame sensing electrode and lead connections

2. Electrode position

YES

Flame current should be 1 µA approx.

NO

Replace PCB

Replace flame sensing electrode

J

Overheat thermostat operated or faulty, i.e. continuity across thermostat terminals

YES

Replace

PCB

NO

Allow to cool. Continuity across thermostat terminals more than 1.5 ohm

YES Replace safety thermostat

K

Check terminal 1 of ON/OFF/RESET selector is in connection with PCB - M1 connector terminal 16

Check electrical continuity across terminals 1 & a of ON/OFF/RESET selector when turned to position R

NO

YES

Replace ON/OFF/RESET selector

Replace PCB

41

42

154

63

72

101

22

140

131

41

135

23

15.0 Short Parts List

Short Parts List

44

Key G.C.

Description

No. No.

22 E66 383 Fan

Manufacturers

Part No.

248001

23 393-497 Pressure Switch

32 E66 393 Heat Exchanger

41 E66 398 Burner

44 E66 402 Injector - 1.28 NG

44 Injector - 0.77 LPG

59 E66 408 Electrode Lead

248211

248037

63 E66 432 Spark or Sensing Electrode 247384

72 E66 413 Pump Complete 248244

247380

248016

248029

248210

101 E66 402 Hydraulic Outlet Assembly 248061

102 E66 434 Valve - 3-Way Assembly 248062

103 343 619 Pressure Differential Assy 248063

131 E05 234 Temperature Sensor

135 E66 697 Safety Limit Thermostat

140 E25 126 Gas Valve

154 E66 450 PCB

169 E66 453 Pressure Gauge

248068

248078

245341

248075

248090

59

102

103

169

32

Baxi UK Limited manufacture a comprehensive range of products for the domestic heating market.

Gas Central Heating Boilers

(Wall, Floor and Fireside models).

Independent Gas Fires.

Renewal Firefronts.

Gas Wall Heaters.

Solid Fuel Fires.

If you require information on any of these products, please write, telephone or fax to the Sales Department.

43

Comp N o 247936 - Iss 6 - 6/02

After Sales Service

08706 096 096

Technical Enquiries

08706 049 049

Baxi UK Limited

Brownedge Road

Bamber Bridge Preston

Lancashire

PR5 6SN www.baxi.com

921.648.3