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  • Gas oven FFV/FFD

    From Harry Bloomfield Esq@21:1/5 to All on Wed Jul 16 20:21:19 2025
    Hi all,

    Is there any gas appliance expertise in this forum?

    FFV/FFD = flame failure valve/device.

    It's a Stoves double oven, small one at the top, larger one at the
    bottom. The smaller top one, being the most used. Recently, the small
    oven has been getting not so hot, as normal, so I cleaned the burner,
    checked the jet was clear, then began investigating the controls...

    You turn it on, and the spark ignition begins, and stops once alight,
    detected by ionisation, on the ignition electrode, as it should, except
    the burner flame was far too low.

    Gas flows through a temperature control valve, controlled by a
    thermocouple, mounted in the oven cavity. It then feeds into a FFV/FFD,
    which is operated by a second thermocouple, which is in the flame.

    The FFV, has no wiring to it, just the thermocouple.

    What I have found, is that the FFV holds back the main level of
    gas/flame, until the thermocouple is hot enough, except the tiny amount
    of flame after ignition, is not enough to open the FFV.

    If I switch the oven on, and apply a blowlamp flame to the FFV, for a
    few seconds, the oven will come up to a full flame, heat up quickly, and
    work entirely normally.

    This obviously lead me to believe that either the FFV is faulty, or
    there is an obstruction in the small passage, of the FFV.

    Am I correct, in thinking that the FFV, has an always open small gas
    passage through it, to allow an initial small amount of flame? I have in
    mind to next remove the FFV, and try blowing it through with compressed
    air, working on the assumption that some dirt from the gas, may be
    obstructing it.

    Please, no advice about gas work - I consider myself more than equal to competent.

    --- SoupGate-Win32 v1.05
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  • From Harry Bloomfield Esq@21:1/5 to Harry Bloomfield Esq on Thu Jul 17 16:26:42 2025
    On 16/07/2025 20:21, Harry Bloomfield Esq wrote:

    This obviously lead me to believe that either the FFV is faulty, or
    there is an obstruction in the small passage, of the FFV.

    Am I correct, in thinking that the FFV, has an always open small gas
    passage through it, to allow an initial small amount of flame? I have in
    mind to next remove the FFV, and try blowing it through with compressed
    air, working on the assumption that some dirt from the gas, may be obstructing it.

    I pulled it apart a second time, to investigate the FFV, tried blowing
    through the valve by mouth, found there was barely any flow through the
    unit, and so tried blowing through with compressed air. The compressed
    air, made absolutely no differance, though heating the thermocouple
    opened it up fully.

    Replacement costs, in my initial searches, only found them for sale at
    costs between £50 and £220, obviously making it not worth repairing, but since then I have managed to find one at a much more reasonable £22
    delivered, which I have ordered.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Harry Bloomfield Esq@21:1/5 to Harry Bloomfield Esq on Thu Jul 24 15:25:23 2025
    On 16/07/2025 20:21, Harry Bloomfield Esq wrote:

    If I switch the oven on, and apply a blowlamp flame to the FFV, for a
    few seconds, the oven will come up to a full flame, heat up quickly, and
    work entirely normally.

    This obviously lead me to believe that either the FFV is faulty, or
    there is an obstruction in the small passage, of the FFV.

    Am I correct, in thinking that the FFV, has an always open small gas
    passage through it, to allow an initial small amount of flame? I have in
    mind to next remove the FFV, and try blowing it through with compressed
    air, working on the assumption that some dirt from the gas, may be obstructing it.

    Please, no advice about gas work - I consider myself more than equal to competent.

    All sorted, installing a replacement FFV. Obviously, the FFV was
    designed to pass a set amount of gas, in order to be able to heat up
    it's thermocouple. Wear and tear, must have caused the volume of gas
    being passed, to less than the volume needed to heat the thermocouple adequately, so the FFV was never opened.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)