1. DL manuals
  2. Worcester
  3. Boiler
  4. 24CDi BF
  5. Installation and servicing instructions

Worcester 24CDi BF Installation and servicing instructions

Manual is about: WALL MOUNTED COMBINATION BOILER FOR CENTRAL HEATING AND MAINS FED DOMESTIC HOT WATER

Summary of 24CDi BF

  • Page 1

    24cdi bf wall mounted combination boiler for central heating and mains fed domestic hot water installation and servicing instructions gc number 47 311 29 boiler output automatic modulating control to domestic hot water and central heating minimum 9.0 kw maximum 24.0 kw important: this appliance is f...

  • Page 2

    1.1 gas safety (installation & use) regulations 1996 (amended 1996) : it is the law that all gas appliances are installed by a competent person in accordance with the above regulations. Failure to install appliances correctly could lead to prosecution. It is in your interest, and that of safety, to ...

  • Page 3

    The standard flue assembly length is from 225mm to 420mm. An extension flue length from 420mm to 560mm is available. A terminal guard, type gc 393 545, is available from tower flue components, vale rise, tonbridge, tn9 1tb. Do not allow the flue terminal fitted to the outside wall to become obstruct...

  • Page 4

    Nominal boiler ratings (10 minutes after lighting) boiler adjusted for g20 (natural gas) output input (net) burner setting gas rate pressure kw btu/h kw btu/h m bar. In. Wg. M 3 /h ft 3 /h 9.0 30,700 10.4 35,500 1.8 0.8 1.1 37.28 24.0 81,900 27.0 92,400 13.2 5.3 2.9 100.0 4 table 1. Flue details hor...

  • Page 5

    5 performance specifications primary water capacity 2.0 litres maximum mains inlet pressure 10 bar minimum mains inlet pressure (working) for max. Hot water flow 1.2 bar minimum mains inlet pressure (working) to operate appliance 0.7 bar maximum central heating flow temperature 82°c nom maximum cent...

  • Page 6

    4.1 the appliance must not be installed in any room containing a bath or shower or in a bedroom or bed-sitting room. Particular attention is drawn to the requirements of the current i.E.E. Wiring regulations and, in scotland, the electrical provisions of the building regulations applicable in scotla...

  • Page 7

    L l k k f f g a m e j f hi d g a b,c see fig. 4 5.1 the flue must be installed as specified in bs 5440:part 1and the building regulations. Note: installations coming under the jurisdiction of building control should adhere to the increased clearances. 5.2 the terminal must not cause an obstruction n...

  • Page 8

    See figs. 5, 6 and 6a 7.1 the system must comply with the requirements of bs 6798 and bs 5449. 7.2 the appliance must not be operated without the system being full of water, properly vented and pressurised. 7.3 the pressure relief valve operates at 3 bar (45lb/in 2 ). The discharge must be directed ...

  • Page 9

    9.1 the size of the flow and return pipework is given in section 3 – table 4. The components required to connect the appliance to an open vent system are available as an optional extra kit. 9.2 the feed and expansion cistern should be arranged so that there is a minimum static head of 0.3 metres (12...

  • Page 10

    11.1. Mains supply : 230v ~ 50hz, 140 watts. External fuse 3a, internal fuses f1 - 2a, f2 - 1.25a (20mm). Spare internal fuses are supplied with the appliance. Refer to fig 14. 11.2. The appliance must be earthed. It must be possible to completely isolate the appliance. 11.3. The mains cable must be...

  • Page 11

    11 mains indicator on/of f switch st8 (l s ) st8 (l r ) st8 (n s ) st15 pin l rel 1 pump st12 pin n optional link room thermostat t ransformer fuse f2 (1.25a slow) fuse f1 (2a slow) n st12 pin l live in green electronics electronics inputs outputs spark indicators settings regulator valve ch demand ...

  • Page 12

    12 fig 11 - electrical connections 13 1 2 3 4 5 6 7 8 9 10 11 12 1. St12-mains 9. Fuse-f2 2. Fuse-f1 10. Cable entry clamp 3. Earth screw 11. St13-24volt controls 4. St8-room thermostat 12. Main harness and clamp and external control 13. Control panel pivot -mains voltage point 5. Cable entry screw ...

  • Page 13

    Note: read this section fully before commencing installation 12.1the appliance is supplied suitable for fitting to a sealed system. If it is to be fitted to an open vent system refer to section 8. 12.2 flue options. The standard flue length is from 225mm to 420mm measured from the appliance casing t...

  • Page 14

    From the outside, make good the gap between the air duct and the brickwork. Fit the flue terminal to the air duct and mark the position of the four fixing holes. Drill four holes 5mm (0.19in.) diameter x 30mm (1.25in.) deep in the wall and fit the wall plugs provided. Fix the flue terminal to the wa...

  • Page 15

    13.1 summary the appliance is dispatched with the controls set to provide a maximum output for domestic hot water and central heating of 24 kw (81,900 btu/h). The appliance automatically modulates to satisfy lower heat loads. Domestic hot water circuit confirm that the mains water supply has been fl...

  • Page 16

    Set the gas valve mode switch to the minimum position. The burner pressure will drop to the minimum setting which should be 2mbar for natural gas. Test for gas soundness at the joint between the burner and the gas valve with leak detection fluid. Note: the burner pressure is factory set and if (afte...

  • Page 17

    Adjust the central heating by-pass valve until the same temperature difference is obtained. See fig. 24. This should be carried out with only a single radiator operating. If thermostatic radiator valves are fitted then one radiator should be left uncontrolled. The bypass valve should never be fully ...

  • Page 18

    15.1 servicing to ensure continued efficient operation of the appliance it must be checked and serviced as necessary at regular intervals. The frequency of servicing will depend upon the particular installation conditions and usage, but once per year should generally be adequate. The extent of the s...

  • Page 19

    16.1 safety switch off the electricity and gas supplies before replacing any components. After the replacement of any components, check for gas soundness where relevant and carry out functional checks as described in section 13 - commissioning 16.2 component access to replace components it is necess...

  • Page 20

    Open the valves and fill and re-pressurise the system as described in section 13.2. 4. Combustion chamber insulation. Refer to fig. 29. Check that the electricity supply to the appliance is turned off. Drain the central heating circuit as described in section 16.3, a. Remove the inner casing cover, ...

  • Page 21

    13. Expansion vessel. Refer to figs. 30,32. Drain the central heating circuit as described in section 16.3, a. Hinge the facia panel into the servicing position as described in section 15.3, c. Remove the gas to water heat exchanger, water to water heat exchanger and pump as described in 16.4, 3,12 ...

  • Page 22

    16. Water diverting valve. Refer to figs. 30,33. Check that the electricity supply to the appliance is turned off. Drain the central heating and domestic hot water circuits as described in sections 16.3, a and b. Hinge down the facia panel into the servicing position as described in section 15.3, c....

  • Page 23

    17. Inlet water filter. Refer to fig. 34. Check that the electric supply to the appliance is turned off. Drain the central heating and domestic circuits as described in sections 16.2, a and b. Hinge down the facia panel into the servicing position as described in section 15.3, c. Follow the procedur...

  • Page 24

    223. Control board. Refer to fig. 35. Check that the electricity supply to the appliance is turned off. Remove the three screws fixing the facia bottom panel to the facia. Remove the facia bottom panel. Retain the panel and screws. Carefully pull off all the connectors. Disconnect the mains supply l...

  • Page 25

    25 17. Short parts list g.C.No. Part whs part no. E01 064 bf standard terminal 225mm- 420mm 7 716 191 007 e01 065 bf extended terminal 420mm- 560mm 7 716 191 008 299 361 digital single channel programmer 7 716 192 003 299 360 mechanical single channel programmer 7 716 192 002 e01 053 digistat cd (ra...

  • Page 26

    26.

  • Page 27

    27 18. Operational flow diagrams main switch on green light on room thermostat and/or mains programmer (or link) on and electronic facia programmer (if fitted) on and st13 link in and ch control knob on central heating demand ch light on. Pump on. Ignition sequence. Burner light on. Three minute wai...

  • Page 28

    28 within four minutes of last hot water demand and primary temperature above 80°c run pump until primary drops to 80°c overrun function and above 9°c commence normal central heating mode until temperature reaches 30°c 5°c to 9°c below 5°c no demand and primary temperature below 8°c internal “autofr...

  • Page 29

    29 no lights at all other faults not covered by above fail point c fail point b fail point e fail point j fail point k fail point a fail point d fail point f fail point g fail point h fail point i no green light (red lights work) no light (other lights work) light on constant (ch knob in off positio...

  • Page 30

    30 is the facia on/off switch turned on? `(clockwise) is there a 230v ac live supply across terminal st12 pins l and n has fuse f1 blown? Replace fuse and investigate cause. Suggestions: cable damage, connections to (or faults within) pump, external 230v controls, transformer or board. Turn switch o...

  • Page 31

    31 red diode is damaged. Replace control board. (section 16.4.22) is there a link at terminal st13 pins 1 and 2? Is there an electronic programmer at position st5 at right- hand end of board? Replace control board. (section 16.4.22). With ch control knob fully clockwise, does the boiler ignite and a...

  • Page 32

    32 boiler is running in “autofrost stat” mode. See section 18. Replace control board. (section 16.4.22). Note: a wet board could cause this fault. Is the boiler in a very cold environment (less than 5°c)? Drop down the facia. Is the gas valve mode switch in the normal position? Turn to normal positi...

  • Page 33

    33 remove front panel. Reset and restart the boiler. Can a flame be seen through the spy glass? Turn off boiler. Remove inner cover and combustion chamber cover. Is the sense electrode and lead in good condition and is gap correct. Remove multiway connector from board position st16. Is there continu...

  • Page 34

    34 remove multiway connector from board position st16. Test resistance across contacts 17 and 18 (yellow wires). Is it between 1 kohm and 30 kohm? Test resistance across contacts 12 and 13 (red wires). Is it between 1 kohm and 30 kohm? Test resistance across contacts 7 and 8 (brown wires) and 9 and ...

  • Page 35

    35 light indication during fault not covered by above details. Control board is likely to be wet or damaged or malfunctioning. Check for wet board or connections. Dry and re-use or replace control board. (section 16.4.23). Fail point k hot water temperature always too hot during a demand (not regula...

  • Page 36

    This booklet is accurate at the date of printing but will be superseded and should be disregarded if specifications and/or appearances are changed in the interests of continued improvement. All goods sold are subject to our official conditions of sale, a copy of which may be obtained on application....