1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Worcester 24i won’t ignite

Discussion in 'Plumbing and Central Heating' started by art1960uk, 24 Sep 2018.

  1. art1960uk

    art1960uk

    Joined:
    24 Sep 2018
    Messages:
    1
    Thanks Received:
    0
    Hello people, I have a Worcester 24i boiler that would not power up.

    I replaced the pcb board with one off ebay and now the problem I have is the boiler comes on but won’t ignite.

    The fan is spinning and everything sounds like it about to ignite.

    I can here the air pressure switch click when I turn the boiler on .

    Any ideas ?

    Thanks
     
  2. adam911

    adam911

    Joined:
    21 Mar 2016
    Messages:
    130
    Thanks Received:
    1
    Country:
    United Kingdom
    Does the boiler spark? You'll notice small clicking sound?
     
  3. Sponsored Links
  4. ollski

    ollski

    Joined:
    8 Oct 2003
    Messages:
    7,090
    Thanks Received:
    543
    Location:
    Bristol
    Country:
    United Kingdom
    Pretty easy to pull the ignition leads off these when you change the board
     
  5. adam911

    adam911

    Joined:
    21 Mar 2016
    Messages:
    130
    Thanks Received:
    1
    Country:
    United Kingdom
    Here's a general boiler sequence

    HOT WATER DEMAND


    1. Demand for DHW
    2. Domestic hot water flow switch operates (continuity)
    3. Control PCB sends 240Vac to the pump and the pump runs.
    *** If the pump fails no fault condition is displayed, but boiler will still operate
    4. The C'HTG (primary) NTC is checked to see if in range.
    *** If the primary NTC is faulty then only the pump will run. Also if the DHW NTC is faulty, it
    will not cause the boiler to fail.
    5. Ignition PCB checks Air Pressure Switch for closed circuit(continuity) between Common and
    Normally Closed
    6. Ignition PCB sends 240Vac to the fan and the fan runs.
    7. Air Pressure Switch operates giving continuity between Common and Normally Open.
    ***If no continuity the fan continues to run for 60 seconds, the Orange Flame Failure light
    illuminates and the fan stops.
    8. Ignition PCB energises spark generator and spark commences.
    9. Simultaneously the PCB sends 240Vac to the Pilot Solenoid on the gas valve and the pilot lights.
    10. Flame rectification takes place and 240Vac is sent to the main Gas Valve Solenoid, allowing
    gas to the burner.
    11. Main burner ignites, and the voltage at the modureg increases to give the required gas
    pressure (max voltage 15Vdc, this giving full gas pressure)
    ***Any failure at points 7,8 and 9 will result in flame failure fault condition-
    after approx 40 seconds the orange Flame Failure Light will illuminate, the appliance will
    lockout and the pump will run continuously.
    12. Water temperatures are maintained under the control of the DHW NTC in conjunction with the
    gas valve (modureg), hot water potentiometer and the PCB.
    *** If the DHW NTC fails then HW is still provided but no modulation of the gas valve takes
    place and the water temperature is higher with much more boiler noise
     
  6. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
  7. Sponsored Links
Loading...

Share This Page