CE Mark

This boiler meets the requirements of Statutory Instrument, No. 3083 The Boiler (Efficiency) Regulations, and therefore is deemed to meet the requirements of Directive 92/42/EEC on the efficiency requirements for new hot water boilers fired with liquid or gaseous fuels. Type test for purposes of Regulation 5 certified by: Notified body 0063. Product/production certified by: Notified body 0086. The CE mark on this appliance shows compliance with: 1. Directive 90/396/EEC on the approximation of the laws of the Member States relating to appliances burning gaseous fuels. 2. Directive 73/23/EEC on the harmonisation of the Laws of the Member States relating to electrical equipment designed for use within certain voltage limits. 3. Directive 89/336/EEC on the approximation of the Laws of the Member States relating to electromagnetic compatibility.
Introduction - Manual Handling
IMPORTANT. With regards to the Manual Handling Operations, 1992 Regulations, the following lift operations are recommended as the appliance weight exceeds a one man lift.
Carriage of carton from point of delivery to point of installation - roofspace.
Recommend 2-person lift. Ensure co-ordinated movements during lift. Avoid upper body/top heavy bending - do not lean forward/sideways. Clear the route before attempting the lift. Take care to avoid trip hazards, slippery or wet surfaces and when climbing steps and stairs. When transferring appliance into roofspace, recommend 1 person to be in roofspace to receive the appliance and other person to be below to pass up and support appliance. Ensure safe lifting techniques are used - keep back straight - bend using legs. Keep load as close to body as possible. Always use assistance if required. It is assumed safe access, flooring and adequate lighting are provided in the roof space. It is recommended a risk assessment of the roof space area be carried out before moving the appliance into the area to take into account access, stability of flooring, lighting and other factors, and appropriate measures taken.
General recommendations when handling
Clear the route before attempting the lift. Ensure safe lifting techniques are used - keep back straight bend using legs. Keep load as close to body as possible. Do not twist - reposition feet instead. If 2 persons performing lift, ensure co-ordinated movements during lift. Avoid upper body/top heavy bending - do not lean forward/ sideways. Recommend wear suitable cut resistant gloves with good grip to protect against sharp edges and ensure good grip. Always use assistance if required.
Unpacking of Appliance from carton.
Recommend 2 persons unpack appliance from carton. Always keep working area clear. Recommend cut base end of carton and open carton flaps, then tilt boiler forwards from its side onto its base and remove carton by sliding up over the boiler. Ensure safe lifting techniques are used - keep back straight - bend using legs. Keep load as close to body as possible. Always use assistance if required. Dispose of packaging in a responsible manner. Recommend wear suitable cut resistant gloves with good grip to protect against sharp edges and ensure good grip when handling appliance outside packaging.

Positioning of Appliance for Final Installation - in roof space restricting installation.
Recommend 2 persons lift appliance to position into place, space permitting. Fit bracket securely onto wall before lifting appliance into position. Obtain firm grip on front and sides of appliance, lift upwards, ensure stable balance achieved and lift upwards to drop into place onto bracket. If 2 persons positioning onto bracket obtain firm grip at front and sides/base of boiler. Ensure co-ordinated movements during 2 person lifts to ensure equal spread of weight of load. If 1 person positioning onto bracket recommend obtain firm grip supporting base of boiler. Ensure safe lifting techniques are used - keep back straight bend using legs - when lifting load from floor level. Do not twist - reposition feet instead. Keep boiler as close as possible to body throughout lift to minimise strain on back. Always use assistance if required. Recommend wear suitable cut resistant gloves with good grip to protect against sharp edges and ensure good grip when handling appliance. It is recommended a risk assessment of the roof space area be carried out before moving the appliance into the area to take into account access, stability of flooring, lighting and other factors, and appropriate measures taken.
User Instructions - Appliance Introduction
The EnviroPlus F24e & F28e boilers are wall mounted high efficiency condensing combination boilers with electronic ignition providing central heating and instantaneous hot water. The EnviroPlus F28e SB boiler is a wall mounted high efficiency condensing system boiler with electronic ignition providing central heating and indirect hot water. Both the central heating and domestic hot water (F24e & F28e only) temperature are user adjustable. F24e & F28e ONLY Domestic hot water demand always has priority over heating demand. The boiler is designed for use as part of a sealed water central heating system with fully pumped circulation. The pump, expansion vessel and associated safety devices are all fitted within the boiler. The boilers have fan assisted balanced flues which both discharges the products of combustion to and draws the combustion air from the outside of the room. The boilers are suitable for horizontal top, vertical flue or twin-pipe flue system connection. Refer to section 8 of these instructions and the Saunier Duval flue options guide (available from your nearest stockist) for further information. Manufacturer's instructions must not be taken as overriding statutory requirements. Reference in these instructions to British standards and statutory regulations/requirements apply only to the United Kingdom. For Ireland the current edition of I.S.813 "Domestic Gas Installations" must be used. These instructions should be carefully followed for the safe and economical use of your boiler. Note: The boiler serial number is marked on the data label attached to the inner casing panel. The 'Controls & lighting' section describes how to safely use the boiler.

Diagram 4

Diagram 5
To set the programmer ON and OFF times
Note: The programmer can be set to give a minimum of one and a maximum of three "ON" and "OFF" times. Place the slide switch to "SET". Press the "enter" button. The display will show the first "ON" time, see diagram 5. Using the + and - buttons, change the first "ON" time to the time you require then press the "enter" button twice. This stores the new time and displays it to confirm it has been stored in the programmer memory. Press the "enter" button again. The display will show the first "OFF" time, see diagram 6. Using the + and - buttons, change the first "OFF" time to the time you require. Press the "enter" button twice. The display will show the first "ON" time. Press the "enter" button again. The display will now show the first "OFF" time you have just entered. Repeat the above for the remaining "ON" and "OFF" times. When the "ON" and "OFF" times have been set, place the slide switch to "RUN". Note: If all three "ON" and "OFF" times are not required, follow the above instructions but after setting the desired times, set the other times to show a series of dashes, using the + and buttons, see diagram 7. The series of dashes are between times 23.59 and 0.00. Helpful Hint If you get confused and wish to start again, press the "Reset" (res) button and the programmer will revert to the internal factory set programme. You can now reset the current time and start again.

Diagram 6

Diagram 7
The programmed "ON" and "OFF" times can be checked at any time by moving the slide switch from "RUN" to "SET". Successive presses of the "enter" button will show the "ON" and "OFF" times. Always return the slide switch to "RUN" to return to normal timed working.
To set the 'Holiday' feature
The programmer has a holiday feature which can be set, if required, to keep the central heating "OFF" for a period between one hour and twenty seven days. This can be used, for example, to keep the central heating "OFF" during a holiday. After the programmed time has elapsed, the boiler will return to its normal programmes and switch on the boiler in time for a return from holiday. Place the slide switch to " HOL " , the letter "h" will appear on the display, see diagram 8. Using the + and - buttons, set the "Holiday" time required. After the display has shown "twenty three hours", the "h" symbol on the display will change to a "d". The Holiday time will now be displayed in days, instead of hours, see diagram 9. Use the "ON/OFF" button to set the boiler to the required operation during the "Holiday" period. Place the slide switch to "RUN". After the programmed "Holiday" time, the boiler will return to normal timed operation.

3.2 Filling the Sealed System
NOTE: The water pressure at the boiler must be at least 1.2bar to enable filling the boiler to a minimum pressure. If not pressurisation must be carried out by an alternative filling loop. The boiler has a built in filling device, see diagram 3.3. A pushon extension is supplied in the loose items pack to ease access to the filling device tap. This filling device is designed to enable the re-pressurisation of the system in the event of loss of pressure. It is not intended to be used to completely fill the system. If so used, it may take a long time to fill the system. Refer to diagram 3.3. Using the tap extensions connected to tap (a) and tap (b) open tap (b) and then slowly open tap (a). Repressurise the system to a pressure of 1.0 bar indicated on the digital display with no demand. When the system is pressurised you must close tap (b) and then tap (a). To fill the system quickly provision should be made to include a proprietry filling loop external to the boiler. Suitable external filling systems are shown diagramatically, see diagram 3.4. The system should be pressurized to 1 bar, indicated on the digital display with no heating demand.

3.3 Water Treatment

In the case of an existing installation, it is ESSENTIAL that prior to installing the new boiler the system is thoroughly flushed. For optimum performance after installation of a new system, the boiler and its associated central heating system should also be flushed. Flushing should be carried out in accordance with BS7593: 1992 using a cleanser such as Sentinel X300 or X400, or Fernox Superfloc. For long-term corrosion protection, after flushing, an inhibitor suitable for cast aluminium exchangers should be used, refer to the current issue of BS 5449 and BS 7593 on the use of inhibitors in central heating systems.

BOILER Filling device

DOMESTIC WATER

3.1 Bypass

NOTE: All systems must have at least one radiator not fitted with a thermostatic valve. The boiler is fitted with a fixed bypass. Ensure that the flow rate does not drop below the figure specified, see diagram 3.1. A bypass is not required on the central heating circuit unless the system controls could allow the boiler to operate when there is no flow. Where an additional bypass is fitted, it must be placed at least 1.5 metres from the appliance, see diagram 3.2.

BYPASS (if required)

ADDITIONAL EXPANSION VESSEL (if required)
HEATING CONTROL CIRCUIT VALVE RETURN DRAIN POINT

Diagram 3.2

COLD SUPPLY IN

HOT OUT

Boiler
Additional expansion vessel (if required)
Bypass (if required) Control valve Drain point

Heating circuit

Return

Diagram 3.2a

TYPE CA
FILLING LOOP TAP (b) EXTENSION Diagram 3.3 Diagram 3.4
4 (F24e & F28e ONLY) Domestic Hot Water System Design
All domestic hot water circuits, connections, fittings must be in accordance with the relevant standards and water supply regulations. For GB: Refer to the current addition of the Water Regulations Guide. For IE: The current edition of I.S.813 "Domestic Gas Installations". - Copper tubing or plastic Hep20 may be used for the domestic hot water system. Unnecessary pressure losses should be avoided. - Provision shall be made for a drain valve at the lowest point of the system. - The boiler will operate with a supply pressure of 0,6 bar, but under reduced flow rate. In these circumstances the filling loop will not pressurise the boiler. Best operating comfort will be obtained from a supply pressure of 1 bar.

4.1 Hard Water Areas

In areas where the water is 'hard', more than 200mg/litre, it is recommended that a proprietary scale reducer is fitted in the cold water supply to the boiler.

5 Boiler Schematic

(F24e & F28e ONLY)

Diagram 5.1

BYPASS

(F28e SB ONLY)

Diagram 5.1a
6 Boiler Location, Flue and Ventilation

6.1 Location

This boiler is not suitable for outdoor installation. This boiler may be installed in any room, although particular attention is drawn to the installation of a boiler in a room containing a bath or shower where reference must be made to the relevant requirements. The boiler must NOT be installed in a cupboard. In GB this is the current I.E.E. WIRING REGULATIONS and BUILDING REGULATIONS. In IE reference should be made to the current edition of I.S.813 "Domestic Gas Installations" and the current ETCI rules.
The boiler must be mounted on a flat wall, which is sufficiently robust to take its weight, see diagram 1.1.

6.2 Clearances

The position of the boiler must be such that there is adequate space for servicing. The recommended clearances are shown in diagram 6.1. The minimum acceptable spacings from the terminal to obstructions and ventilation openings are shown in diagram 6.2. For Ireland the minimum distances for flue terminal positioning must be those detailed in I.S.813 "Domestic Gas Installations". The terminal must be exposed to the external air, allowing free passage of air across it at all times. Being a condensing boiler some pluming may occur from the flue outlet. This should be taken into consideration when selecting the position for the terminal. Carports or similar extensions of a roof only, or a roof and one wall, require special consideration with respect to any openings, doors, vents or windows under the roof. Care is required to protect the roof if made of plastic sheeting. If the carport comprises of a roof and two or more walls, seek advice from the local gas supply company before installing the boiler.

7.2 Wall Template

Remove the wall template from the installation pack and place in the desired position on a flat wall, giving due consideration to boiler clearances, see section 6.

7.4 Appliance Fixing

Reposition the wall template mark the position of the hanging bracket fixing holes. Drill the fixing holes and insert suitable wall plugs. Fix the hanging bracket to the wall using suitable screws, see diagram 7.2. Lift the boiler into position in the following manner. Lean the top of the boiler slightly to the wall and position just above the hanging bracket. Allow the boiler to slowly move downwards until engaged in the hanging bracket.
7.3 Horizontal Flue Hole Cutting
Mark the centre of the flue hole and remove the wall template. The standard horizontal flue is designed with an internal fall of 35mm/metre towards the boiler for disposal of condensate. If the standard flue length alone is being used then the flue hole of diameter 105mm can be cut in the position marked on the wall template. For standard side flues the horizontal flue centre line on the wall template should be extended to the side wall, and the vertical centre of the flue hole marked at 206mm from the back wall. For installations with external access, a 105mm diameter core drill can be used. For installations with internal access only a 125mm diameter core drill should be used.
206mm Horizontal - Standard flue 2.5 Inclined Extended flue length EXTERNAL FITTING 125 INTERNAL FITTING WALL PLUG

FRONT CASING PANEL

105 Standard 125 Extended

HANGING BRACKET

WALL TEMPLATE SECURING SCREWS Diagram 7.1 SCREW Diagram 7.2
8 Horizontal Top Flue Preparation and Fitting
The standard horizontal flue is fitted onto the top of the boiler using the flue adaptor. See diagrams 8.1 to 8.3 to determine whether a standard flue can be used. The standard flue can be extended using 1m long extension kits and 90 elbows to maximum equivalent length of 3.5m - Note: A 90 elbow equals 1m of flue. When extension pipes are used the flue system must be designed to have a continuous fall to the boiler of at least 2.5 to allow condensate to run back into the boiler and out via the drain. Horizontal Internal Flue Installation The flue can be installed from inside the building, when access to the outside wall face is not practicable. WALL THICKNESS 'X' = 75 TO 527mm

FITTING FLAT ROOF FLASHING FITTING PITCHED ROOF FLASHING VERTICAL ROOF TERMINAL 565 100

TERMINAL

1x90 or 2x45 ELBOWS 1 METRE EXTENSION 730

FLAT ROOF FLASHING

1 METRE EXTENSION PITCHED ROOF FLASHING Fit flat roof or pitched weather collar onto vertical roof terminal. Make sure a weather proof seal is made in accordance with good building practice. VERTICAL ROOF TERMINAL
1 METRE EXTENSION 1x90 or 2x45 ELBOWS
400-500mm ADJUSTABLE PIPE VERTICAL FLUE ADAPTOR

140 1195

* FIXING BRACKETS

1 METRE EXTENSION

Diagram 8.8

Diagram 8.9

8 Twin Flue Preparation and Fitting
TWIN FLUE ADAPTOR KIT Pt.No.A2025000 TWIN PIPE TO CONCENTRIC ADAPTOR Pt.No.08511800 PITCHED ROOF WEATHER COLLAR Pt.No.08510500 1M EXTENSION Pt.No.08547800 (Aluminium)
0.5M EXTENSION Pt.No.08547600 (Aluminium)
FLAT ROOF WEATHER COLLAR Pt.No.08510700 SINGLE PIPE TO TERMINAL ADAPTOR Pt.No.08511900
0.5M EXTENSION AIR DUCT Pt.No.08547200 (Plastic)

45 BEND Pt.No.08538800

HORIZONTAL FLUE TERMINALS Pt.No.08511500
FIXING BRACKET VERTICAL Pt.No.08512000
FIXING BRACKET TWIN FLUE Pt.No.08511700
CONCENTRIC HORIZONTAL TERMINAL Pt.No.BEND Pt.No.08538700 Diagram 8.10

8.10 Twin Flue

These instructions are for the installation of this twin flue and its accessories only. Diagram 8.10 shows the Twin Flue Adaptor kit and Accessories. Refer to the Flue Options Guide available from your nearest stockist for flue lengths and sample installations. Lubricate the rubber seals prior to inserting flue pipes. Make sure all joints are properly fitted, sealed and secured. Remove all burrs from cut pipes. If an extension pipe requires cutting, cut the plain end not the flared end where the sealing rings are fitted. Your selected flue arrangement must be secured with fixing brackets. One fixing bracket to be used for every metre of flue pipe used. The terminal should be positioned as to cause the least problem with the dispersal of products of combustion and any pluming that may occur. The use of weather collars are the preferred method when installing the roof terminal.
FLUE CONFIGURATION EXAMPLE INCLUDING DIMENSIONS TO AID CUTTING AND INSTALLATION AIR DUCT 45ELBOW TERMINAL 50 50

1 METRE EXTENSION 90ELBOW 1 METRE EXTENSION

FLUE DUCT TERMINAL

1 METRE EXTENSION TWIN FLUE ADAPTOR

Diagram 8.11

TWIN FLUE ADAPTOR
An Example Twin Flue Installation. (The flue assembly is an entirely push fit design), see diagram 8.11. Fitting Twin Flue Adaptor, see diagram 8.12. Fitting Twin Flue Terminals, see diagram 8.13. Fitting Concentric Horizontal Terminal, see diagram 8.14. Fitting Vertical Roof Terminal, see diagram 8.15. Fitting Weather Collars, see diagram 8.16.

SUPPORT BRACKET

Diagram 8.12

90ELBOW

12203 11742
SEALING COLLARS 1 METRE EXTENSION (cut to fit) 90ELBOW AIR DUCT TERMINAL

SEALING COLLARS

FLUE DUCT TERMINAL Diagram 8.13

CONCENTRIC ADAPTOR

INTERNAL SEALING COLLAR
CONCENTRIC HORIZONTAL TERMINAL
EXTERNAL SEALING COLLAR Diagram 8.14
VERTICAL ROOF TERMINAL 565

VERTICAL ROOF TERMINAL

After installation the vertical roof terminal must be secured with a fixing bracket
SINGLE CONCENTRIC PIPE ADAPTOR ADAPTOR
Fit flat roof or pitched weather collar onto vertical roof terminal. Make sure a weather proof seal is made in accordance with good building practice. PITCHED ROOF FLASHING

SINGLE PIPE ADAPTOR

445 CONCENTRIC ADAPTOR
VERTICAL ROOF TERMINAL 1195
1 METRE EXTENSION CONCENTRIC ADAPTOR
SINGLE PIPE ADAPTOR Diagram 8.15 Diagram 8.16
9 Gas/Water Connections These packs are for the (F24e & F28e ONLY)
Packs supplied with the boiler
1. Isolating valve pack containing Heating isolating valves (2 off) Domestic cold water isolating valves (1 off) Domestic hot water elbow (1 off) Gas isolating valve (1 off) 2. Safety discharge pipe pack containing Safety discharge valve pipe (1 off) 15mm seal washer (1 off) Tubing nut (1 off) 3. Installation pack containing Installation manual (inc. guarantee card) 15mm seal washer (1 off) a Polyacetal gasket (4 off) d Wall template (1 off) Filling device extensions (2 off) 3 pole inline plug (1 off) Securing screws (3 off) Condense adapter (1 off)

WALL TEMPLATE

4. Pipe pack containing Central heating pipe (2 off) Domestic water pipe (2 off) Gas pipe (1 off) 1/2 in. gasket (3 off) b 3/4 in. gasket (2 off) c

Make sure that : The boiler is connected to the electrical supply. The gas service cock is open. Switch OFF (0)
Switch ON (I) Fill the system until the pressure gauge reads 1.0 bar, reter to Section 3.2and 3.3.
Open the three boiler isolating valves. The slot of the screw corresponds to flow direction. (Turn anti-clockwise to open fully)
CENTRAL HEATING FLOW ISOLATING VALVE Bleed each radiator to remove air, ensure all bleed screws are re-tightened. If necessary repressurise the system, refer to procedure 4.
Leave cap on automatic air vent on top of boiler open. (see procedure 3) (F24e & F28e ONLY) DOMESTIC COLD WATER ISOLATING VALVE CENTRAL HEATING RETURN ISOLATING VALVE
Flush the domestic hot water system by opening the hot water taps for several minutes.
Ensure the display indicates a system pressure of 1.0 bar, adjust if necessary, refer to Section 3.2.

(F24e/F28e SHOWN )

12.3 Initial Lighting
- Adjust heating temperature to maximum, refer to User Controls and Lighting. - Check that any system controls, if fitted, are calling for heat (set room thermostat to maximum). - Allow the temperature to rise to the maximum value, with all radiator valves open. The temperature rise will cause release of the gases contained in the water of the central heating system. - Gases driven towards the boiler will be automatically released through the automatic air vent. The gases trapped at the highest point of the system must be released by bleeding the radiators. - Check the burner gas rate required, ten minutes after lighting. Refer to Data Label on the inner casing panel. Should there be any doubt about the gas rate it should be checked at the meter. The approximate gas rate is for guidance only (MAX.) 2.7 m3/h (97 ft3/h) (MIN.) 0.5 m3/h (19 ft3/h) On reaching maximum temperature, the boiler should be turned off and the system drained as rapidly as possible whilst still hot. - Refill system to a pressure of 1.0 bar and vent as before. - Restart boiler and operate until a maximum temperature is reached. Shut down boiler and vent heating system. If necessary, top up heating system and make sure that a pressure of at least 1 bar is indicated when system is COLD.

12.5 Instruct the User

Instruct and demonstrate the lighting procedure and advise the user on the safe and efficient operation of the boiler. Instruct on and demonstrate the operation of any heating system controls. Advise the user on the use and maintenance of any scale reducer and pass on any relevant instructional documents. Advise that to ensure the continued efficient and safe operation of the boiler it is recommended that it is checked and serviced at regular intervals. The frequency of servicing will depend upon the installation conditions and usage, but in general, once a year should be enough. Draw attention, if applicable, to the current issue of the Gas Safety (Installation and Use) Regulations, Section 35, which imposes a duty of care on all persons who let out any property containing a gas appliance in the U.K. The user shall not interfere with or adjust sealed components. It is the Law that any servicing is carried out by a competent person. Advise the user of the precautions necessary to prevent damage to the system, boiler and the building, in the event of the heating system being out of use during frost or freezing conditions. Advise the user that the permanent mains electrical supply SHOULD NOT be switched off, as the built in frost protection and pump saver (anti sieze) program would not be operable. Reminder, leave these instructions and the 'Benchmark' logbook with the user. For IE, it is necessary to complete a "Declaration of Conformity" to indicate compliance to I.S.813. An example of this is given in the current edition of I.S.813.
12.4 DHW Pre-heat Function
There is a domestic hot water pre-heat function which is factory set to on. With pre-heat "On" the boiler will light every hour, or after a demand, to reheat the primary domestic hot water circuit if necessary. The pre-heat function can be turned off if required but the DHW response will be affected. To turn the pre-heat off, slide dip switch 1 to the 'ON' position. Refer to section 11.3 to gain access to the user interface PCB. On completion adjust the temperature control and any system controls to their required settings. In addition it is neccessary to complete the "Benchmark" logbook. For IE, it is neccessary to complete a "Declaration of Conformity" to indicate compliance to I.S.813. An example of this is given in the current edition of I.S.813. Testing Flue Gases: If any doubt exists that the flue products are not exhausting correctly, investigate by use of a gas analyser (FGA).

DIP SWITCH preheat OFF

DIP SWITCH preheat ON

USER INTERFACE PCB

Diagram 12.1

13 Servicing

13.3 Burner and Fan

HEATING FLOW ELECTRICAL CONNECTIONS
SECURING PLATE SCREW (Slacken pull forwards to remove)

SPARK ELECTRODE LEAD

LEDGE FAN SECURING PLATE

13.4 Heat Exchanger

The heat exchanger does not require cleaning during servicing.

GASKET

FAN ELECTRICAL CONNECTIONS GAS PIPE SECURING CLIP
GAS VALVE ELECTRICAL CONNECTIONS
BURNER SECURING SCREW (2) FAN SEAL

SECURING SCREW (2)

SPARK ELECTRODE
SPARK GAP 3.5 to 4.5mm GAS VALVE, FAN AND SILENCER ASSEMBLY

Diagram 13.3

Diagram 13.4
Refer to diagram 13.5 and 13.6. Remove condensate drain pipe. Slide fixing bracket forward and remove, ease condensate drain down off the inlet connection. Carefully remove the condense drain taking care not to spill any water which may be in the unit. As the unit is lifted remove the flexible connection on the outlet. Remove the cap at the base of the condense trap. Remove any solids found. Remove the strainer and clean. Remove the float, clean and check it floats. Flush water through the trap to remove any remaining solids. Check for any debris in the outlet pipe of the condensate drain and clean as necessary. Reassemble and fill the trap with water, refit the condensate drain. When refitting the cap ensure that a watertight seal is achieved, but do not use excessive force.

FIXING BRACKET

CONDENSATE DRAIN PIPE DOMESTIC HOT WATER OUTLET COUPLING (F24e/F28e SHOWN ) Diagram 13.5

13.6 Combustion Check.

Once the appliance has been reassembled (apart from the front and inner casing panels) connect a CO2 combustion analyser to the sample point on the flue elbow, or alternatively to the point at the base of the flue outlet pipe inside the boiler casing, see diagram 13.2. Turn on the gas service cock, see diagram 9.2. With the power off and the appliance cold, unclip the controls fascia and hinge it down to reveal the potentiometers on the rear of the User interface, see diagrams 13.7 and 13.8. Take care not to allow the fascia to drop down and damage the wiring. Turn on the electrical supply. Ensure external controls are calling for heat. The boiler should fire automatically. Allow the boiler to fire for a minimum of 60 seconds and then, using an electrical screwdriver, rotate the service potentiometer fully clockwise, see diagram 13.8. This will allow the digital display to indicate the 'flashing' fan speed on the appliance fascia. In the fully clockwise position the display should be indicating the maximum fan speed of the appliance, this should be 54. Check the CO2 value, which should be 9.2% 0.2%. Note that with the inner case front panel fitted the combustion readings will increase slightly to 9.3% 0.3%. If adjustment proves necessary then proceed as follows. Any adjustment to the gas valve should only be carried out by a competant person. Refer to diagram 13.9. Adjust the maximum rate CO2 with the throttle to 9.2%. (Rotate anti-clockwise to increase). Rotate the service potentiometer fully anti-clockwise. Hold it in this position for about 5 seconds before rotating the service potentiometer clockwise to the mid-point or 3 o'clock position. The fan should reduce to 1300 rpm which will flash '13' on the LCD display. Check the CO2 value, which should be 8.3% 0.2%. If adjustment proves necessary then proceed as follows. 43

SECURING CLIP

16.13 (F24e/F28e ONLY) Domestic Hot Water Thermistor
For access, refer to section 16.1. Refer to diagram 16.10. Remove the electrical connections from the thermistor. Remove the thermistor and retaining clip. Fit the replacement thermistor using the heat sink compound supplied. Note: When reconnecting electrical connections, polarity is not important. Carry out a functional test of the controls.
COUPLING (F24e & F28e SHOWN )

Diagram 16.9

DOMESTIC HOT WATER THERMISTOR
16.14 Central Heating Flow Thermistor
For access, refer to section 16.1. Refer to diagram 16.11. Remove the electrical connections from the thermistor. Remove the securing screw from retaining clip. Fit the replacement thermistor using the heat sink compound supplied, do not overtighten when replacing securing screw. Note: When reconnecting the polarity of the wiring to thermistors is unimportant.

(F24e/F28e ONLY)

Diagram 16.10
CENTRAL HEATING FLOW THERMISTOR

Diagram 16.11

16.12 Safety Discharge Valve
16.15 (F24e/F28e ONLY) Central Heating Return Thermistor
For access, refer to section 16.1. Refer to diagram 16.12. Remove the electrical connections from the thermistor. Remove the thermistor and retaining clip from the flow pipe. Fit the replacement thermistor using the heat sink compound supplied. Note: When reconnecting, the polarity of the wiring to thermistors is unimportant.
16.15a (F28e SB ONLY) Central Heating Return Thermistor
For access, refer to section 16.1. Refer to diagram 16.12a. Remove the electrical connections from the thermistor. Remove the thermistor and retaining clip from the flow pipe. Fit the replacement thermistor using the heat sink compound supplied. Note: When reconnecting the polarity of the wiring to thermistors is unimportant.
CENTRAL HEATING RETURN THERMISTOR

Diagram 16.12

16.16 Overheat Cutoff Thermistor
For access, refer to section 16.1. Note: It may be necessary to remove transformer refer to section 16.5. Refer to diagram 16.13. Positioned at the rear left under the fan. Remove the electrical connections from the overheat cutoff thermistor. Remove the thermistor and retaining clip from the flow pipe. Fit the replacement thermistor using the heat sink compound supplied. Note: When reconnecting the polarity of the wiring to thermistor is unimportant.
CENTRAL HEATING RETURN THERMISTOR (F28e SB ONLY) Diagram 16.12a

16.17 Automatic Air Vent

Refer to section 13.9 and drain the boiler heating circuit. Refer to diagram 16.14. Unscrew the automatic air vent. Fit the new automatic air vent and 'O'ring ensuring the vent cap is left loose. Refill, vent and pressurise the boiler. Check for leaks.