Baxi Potterton 21 SL Service Manual Page 1

Installation & Service InstructionsCombi 24This is a Wall Mounted Combination Boiler Gas Fired Central Heating Unit.The boiler meets the requireme

5.0 DIMENSIONS AND FIXINGS10DimensionsA 780mmB 345mmC 450mmD 107mm Ø Min.E 200mmF 190mmG 143mm360° Orientation Tube Ø 100mmDCBAEGF65mm 65mm 65mm 65mmW

116.0 SYSTEM DETAILS6.1 Information1. The Main Combi 24 Combination Boiler is a ‘WaterByelaws Scheme - Approved Product’.To comply with the Water Byel

6.0 SYSTEM DETAILS126.5 System Filling and Pressurising1. A filling point connection on the central heating returnpipework must be provided to facilit

136.0 SYSTEM DETAILS6.8 Domestic Hot Water Circuit1. All DHW circuits, connections, fittings, etc. shouldbe fully in accordance with relevant standard

7.0 SITE REQUIREMENTS147.1 Location1. The boiler may be fitted to any suitable wall with theflue passing through an outside wall or roof anddischargin

157.0 SITE REQUIREMENTS7.3 Ventilation of Compartments1. Where the appliance is installed in a cupboard orcompartment, no air vents are required. Thea

7.0 SYSTEM REQUIREMENTS167.6 Flue1. the following guidelines indicate the generalrequirements for siting balanced flue terminals. ForGB recommendation

177.0 SITE REQUIREMENTSFig. 20100mm1mFig. 19Flue TrimAdhesive SealFig. 17Fig. 187.7 Flue DimensionsThe standard horizontal flue kit allows for flue le

7.0 SITE REQUIREMENTS187.10 Flue Options1. The Main Combi 24 can be fitted with flue systemsas illustrated. 2. The standard flue is suitable only for

198.0 INSTALLATION8.1 Initial PreparationThe gas supply, gas type and pressure must bechecked for suitability before connection (seeSection 7.4).1. Af

2Building Regulations and the BenchmarkCommissioning ChecklistBuilding Regulations (England & Wales) requirenotification of the installation of a

8.0 INSTALLATION208.4 Fitting The Boiler1. Lift the boiler using the lower edges. Engage theslots at the top rear of the boiler on the wall platehooks

218.0 INSTALLATION8.6 Fitting The FlueHORIZONTAL FLUE1. The standard flue is suitable for lengths 100mmminimum to 1m maximum (measured from the edgeof

8.0 INSTALLATION228.6 Fitting the Flue (Cont)IMPORTANT: If the flue length is greater than 1.5mthe restrictor MUST be removed from the adaptor(Fig. 29

238.0 INSTALLATIONL230 VSelector / Reset SwitchExternalControlsNbr bPumpHydraulic Differential Pressure Switchrr3-way Valve MicroswitchbrbkSafety Over

9.0 COMMISSIONING249.1 Commissioning the Boiler1. Reference should be made to BS 5449 Section 5when commissioning the boiler. 2. Open the mains water

259.0 COMMISSIONINGOUTMINPressure Test Point Sealing ScrewGas ValveCentral Heating Temperature ControlHot Water Temperature ControlFig. 42Fig. 43Fig.

10.0 COMPLETION2610.1 Completion1. Hinge the facia panel upwards and engage thesecuring screws. Refit the case front panel and tightenthe screws (Fig.

2711.0 SERVICING11 .1 Annual Servicing1. For reasons of safety and economy, it isrecommended that the boiler is serviced annually.Servicing must be pe

11.0 SERVICING2811.1 Annual Servicing (Cont)10. Remove the spring clips retaining the air box sidebaffle plates. Disengage the tabs on the baffles fro

2912.0 CHANGING COMPONENTSIMPORTANT: When changing components ensurethat both the gas and electrical supplies to theboiler are isolated before any wor

3INSTALLER NOTIFICATION GUIDELINESChoose BuildingRegulations NotificationRouteContact your relevant LocalAuthority Building Control(LABC) who will arr

12.0 CHANGING COMPONENTS3012.3 Heat Exchanger (Fig. 62)1. Note the positions of the two sensing tubes on theoutlet elbow and three wires on the fan mo

3112.0 CHANGING COMPONENTS12.5 Injectors (Fig. 64)1. Remove the burner as described in Section 12.4.2. Undo the screws securing the injector manifold

12.0 CHANGING COMPONENTS3212.8 Gas Valve (Fig. 66)1. Undo the nut on the gas feed pipe under the boiler.2. Completely undo the securing screws and hin

3312.0 CHANGING COMPONENTS12.11 Pump - Head Only (Figs. 68 & 69)1. Drain the primary circuit and remove the sockethead screws securing the pump he

12.0 CHANGING COMPONENTS3412.14 Pressure Gauge 1. Drain the primary circuit and undo the nut on thepressure gauge capillary (Fig. 71).2. Remove th

3512.0 CHANGING COMPONENTS12.17 Pressure Relief Valve (Fig. 78)1. Drain the primary circuit.2. Disconnect the discharge pipe from the valve.Using a su

12.0 CHANGING COMPONENTS3612.20 Plate Heat Exchanger (Fig. 81)1. Drain the primary circuit.2. While supporting the heat exchanger undo thescrews secur

3712.0 CHANGING COMPONENTS12.21 Diverter Valve Assembly (Cont)CH Pressure Differential Valve (Fig. 84)1. Remove the DHW pressure differential valve as

13.0 ELECTRICAL38Optional TimersPumpGas ValveAir PressureSwitchPressure SwitchHydraulic DifferentialTemperature SensorSelector SwitchOn/Off/ResetFanCo

3914.0 FAULT FINDINGCarry out initial fault finding checks1. Check that gas, water and electrical supplies are available at the boiler. Electrical sup

LEGISLATION4Codes of Practice, most recent version shouldbe usedIMPORTANT - Installation, Commissioning, Service & RepairThis appliance must be in

14.0 FAULT FINDING40Domestic Hot Water - Follow operational sequenceTurn selector to neon illuminatedPrimary flow switchoperatedFan runs at max sp

4114.0 FAULT FINDINGFault Finding Solutions Sections A to EIs there 230V at:Is there 230V at:Main terminals L and N Check electrical supply1.NOMain te

14.0 FAULT FINDING42Check and correct if necessary1. Electrical and pressure tube connections2. Blockage of pressure tubes3. Restriction in flue4. Ven

4314.0 FAULT FINDINGCheck and correct if necessary1. Flame sensing electrode and lead connections2. Electrode positionFlame current should be 1 µA app

15.0 SHORT PARTS LIST44Short Parts ListKey G.C. Description ManufacturersNo. No. Part No.22 E66 383 Fan 24800123 393-497 Pressure Switch

4516.0 NOTES

CONTROLS To comply with the Building Regulations, each section must have a tick in one or other of the boxesTIME & TEMPERATURE CONTROL TO HEATING

SERVICE 1DATEENGINEER NAMECOMPANY NAMETEL No.CORGI ID CARD SERIAL No.COMMENTSSIGNATURESERVICE 2DATEENGINEER NAMECOMPANY NAMETEL No.CORGI ID CARD SERIA

Publication No. 5115807 - Iss. 2 (05/2005)All descriptions and illustrations provided in this leaflet have beencarefully prepared but we reserve the r

5CONTENTS1.0 Introduction 62.0 General Layout 73.0 Appliance Operation 84.0 Technical Data 95.0 Dimensions and Fixings 106.0 System Details 117.0 Site

1.0 INTRODUCTION61.1 Description1. The Main Combi 24 is a fully automatic gas firedwall mounted combination boiler. It is room sealed andfan assisted,

72.0 GENERAL LAYOUT2.1 Layout1. Air Pressure Switch2. Expansion Vessel3. Burner Manifold4. Automatic Air Vent5. DHW Plate Heat Exchanger6. Circulation

3.0 APPLIANCE OPERATION8NOTE: All delay timers mentioned in 3.1 and 3.2are overridden by domestic hot water demand.3.1 Central Heating Mode (Fig. 4)1.

94.0 TECHNICAL DATABurner Pressure (Natural Gas - G20)Max Rate Min Ratembar 12.2 ± 0.5 2.5 ± 0.2in wg 4.88 ± 0.2 1.0 ± 0.2Flue Terminal Diameter