Flame-failure device

[Rigger]

I've recently inherited a Plastimo Neptune gas cooker,currently running on butane gas.In order to light the two burners it is necessary to hold the Knobs in for anything up to two minutes,and then slowly release them.If I release too early the flame simply goes out.There does not appear to be a problem with the oven or grill. The previous owner quoted 30 secs holding time (!) and says he has stripped the burners down and cleaned them to no avail.The screws above the knobs are turned clockwise as far as possible ,(turning them the other way makes things worse).Any ideas would be most welcome to avoid the 2 minute hold!

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[plombier]

The thermocouple (safety device used to detect flame before allowing burners to stay alight) is probably wearing/worn out. Suggest a couple of new units would be in order.

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by plombier on 04/02/2004 21:36 (server time).</FONT></P>

 

[pete]

Hi
I assume that the ffd`s are thermocouples, If it had been one burner that was slow I would have said change the t/couple but as they are both slow it may be the flame is not playing on the t/couples tip sufficiently.
Normally around 10 seconds should be enough for a good t/couple but sometimes the burner holes firing the flame on the t/couple can get partialy blocked, If you light the burner, let the flame get established for a few seconds and then blow out the flame the ffd should hold for around 20 seconds (or more depending on the state of the t/couple ) To test them we often play a soft flame on the t/couple just to see if this speeds it up.
Pete

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[ongolo]

Hi Rigger,

The thermo couple generates a small amount of electricity/curent which then holds an the plunger of an electromagnet against spring pressure open. When the thmocouple gets cold, the coil releases the plunger and it closes agian.

Clean the t.couple outside from dirt, make sure that it in exposed to the flames and make sure that the electrical connection where the little copper pipe (shielding the inner wire) is attached soundly on clean metallic surfaces. Contamination with conductive solution (such as salty soup residue) could lead to stray currents that should realy hold the magnet.

The voltages generated by the thermocouple are very small. Most people believe they work like a bi-metal, but that is wrong. Nothing wears out and releasing them slowly or fast should make no difference whether the correctly excited coil holds or not. It sounds like an electrical problem.

regards ongolo


<hr width=100% size=1>1000 dream about it, 100 talk about it, 10 start and 1 completes it

 

[steve28]

Hope this is of help to you ,there is an artical on servicing a neptune 2000 in the pbo this month
when mine was doing this it was due to the burner tops being slightly off line with the thermocouple
After rotating slightly it allowed me to hold in for 5 seconds and then let go.

steve

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