Gas oven FFV/FFD

Jul 16, 2025 Last reply: 11 months ago 2 Replies

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.



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.

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.

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