Is this a Potterton EP2002 Lockout symptom?

Discussion in 'UK DIY' started by ravtek@googlemail.com, Jan 13, 2006.

  1. Guest

    The Potternton EP2002 is a timer control unit for a boiler, mine being
    a Prima F.
    I came home to discover I could not manually press ADV, which would
    normally activate the HW or CH, this is confirmed by the red colout LED
    on the right hand side illuminating.

    Nothing illuminates at all, but the the time is displayed and is
    correct.

    I also discovered that I could not set the time, or modify any other
    settings on the timer unit.

    I removed power to the unit, (fuse isolation) and waited until the LED
    displaying the time faded. But when I turned it back on - SAME
    symptoms, I also noticed the time was exactly the same. So either this
    unit has a large capactitor in there, or a back up battery keeping the
    time backed up... I don't know.

    I do know that I cannot control my heating.

    Should I simply change the unit?

    Regards
    Ravi Tek :(
    , Jan 13, 2006
    #1
  2. Guest

    I have fixed this problem myself.

    Being an engineer I know that some logic circuits with IC can get into
    a lockout, and occasionally need a reset, this circuit in the EP2002
    has a battery back inside, Green coloured thing like 2 watch batteries
    back to back.

    To enable a power outage on this, like you would need to reset the CMOS
    on a PC motherboard.

    I had to take the unit off, disassemble, but not only to view the top
    (component side) but also the underside and short the positive and
    negative terminals on the battery (I used a screwdriver and simply
    touched the solder side terminals for 1 second), this kills the clock
    and brings it back to factory default settings.

    When I finally put it all back together, my mini Christmans tree of a
    timer came back to life.

    Actually thinking about it again, you would only need to take the top
    cover of, and you could bend a paper clip into a "U" shape to shorts
    the terminals.

    This worked for me, and has saved my £50 in a replacement (probably
    more with the labour etc.)

    I answered my own question here in case it helps others. Please do the
    same if you have found a solution to your own.

    Ravi Tekchandani
    Stevenage
    Herts
    , Jan 13, 2006
    #2
  3. raden Guest

    In message <>,
    "" <> writes
    >I have fixed this problem myself.
    >

    Easy if you engage brain isn't it


    --
    geoff
    raden, Jan 14, 2006
    #3
  4. raden Guest

    In message <>,
    "" <> writes
    >The Potternton EP2002 is a timer control unit for a boiler, mine being
    >a Prima F.
    >I came home to discover I could not manually press ADV, which would
    >normally activate the HW or CH, this is confirmed by the red colout LED
    >on the right hand side illuminating.
    >
    >Nothing illuminates at all, but the the time is displayed and is
    >correct.
    >
    >I also discovered that I could not set the time, or modify any other
    >settings on the timer unit.
    >
    >I removed power to the unit, (fuse isolation) and waited until the LED
    >displaying the time faded. But when I turned it back on - SAME
    >symptoms, I also noticed the time was exactly the same. So either this
    >unit has a large capactitor in there, or a back up battery keeping the
    >time backed up... I don't know.
    >
    >I do know that I cannot control my heating.
    >

    Yes, it has a battery for back up

    It's so long since I repaired one I can't remember, but IIRC there's a
    battery in the back

    unscrew it (2 screws on the bottom face and rotate it upwards to remove
    it from the backplate



    --
    geoff
    raden, Jan 14, 2006
    #4

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