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Eno oven flows gas WITHOUT flame

Scott SV Tengah
 

Hi all,

Our Eno oven will flow gas even if there is no flame. My understanding is that the thermocouple is supposed to be stop the flow of gas if there is no flame AND FAILS CLOSED. Is this correct?

Our situation is the opposite. If someone aboard forgets to turn off the oven gas flow completely or if the flame dies, the oven continues to flow gas. This is obviously dangerous. 

We had some issues with the oven and had it serviced prior but the boatyard is not being responsive now. Any ideas on what could be wrong? Given the downside if I screw up, I'm hoping to get some advice before digging in and playing with it. We have the standard oven on a A54, so I think it's the same as the SM.

Thanks!


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com

tony wells
 

Hi Scott

I’m not on the boat and can’t answer your question, sorry, but I am surprised that the A54 is not fitted with a gas alarm/detector under the oven, which should switch off the gas solenoid in the event of detecting gas ie in the precarious scenario experienced by you! I would like to fit an alarm/detector with this functionality - can anyone comment / recommend a model please?

Thanks

Tony
A54 #102 Malta

On 8 Oct 2019, at 14:53, Scott SV Tengah <Scott.nguyen@...> wrote:

Hi all,

Our Eno oven will flow gas even if there is no flame. My understanding is that the thermocouple is supposed to be stop the flow of gas if there is no flame AND FAILS CLOSED. Is this correct?

Our situation is the opposite. If someone aboard forgets to turn off the oven gas flow completely or if the flame dies, the oven continues to flow gas. This is obviously dangerous. 

We had some issues with the oven and had it serviced prior but the boatyard is not being responsive now. Any ideas on what could be wrong? Given the downside if I screw up, I'm hoping to get some advice before digging in and playing with it. We have the standard oven on a A54, so I think it's the same as the SM.

Thanks!


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com

Thomas Kleman
 

Sounds like you have both a technical prob with oven but also a process issue. If someone didn't completely shut the oven off, they should have also closed the gas off with the solenoid. On our boat we have a propane detector which we regularly test. We also test the solenoid. As this is my greatest fear (propane leak) I also physically go to propane locker and shut off gas at the valve. I know that's overkill. It takes me under 60 seconds, and I sleep better.

But bottom line I would never rely on the thermocoupling alone to prevent your under galley spaces from filling up with gas.

Thomas Kleman
SV L'ORIENT
SM2K 422

Scott SV Tengah
 

Thomas,

The process I have implemented is that we turn off the solenoid FIRST and then the gas knobs. 

But humans, especially new/temporary visiting crew not used to doing that on land, sometimes make mistakes, despite all my red tape and written/verbal reminders that gas is dangerous. I want to fix the technical issue as relying on perfect process alone is a recipe for disaster IMO.

Anyone else with knowledge/ideas?

--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com

Craig Briggs SN 68 Sangaris
 

Hi Scott,
Clearly having gas continue to flow with no flame should not be able to occur.  

It sounds like this started happening only after the boatyard worked on the stove - what was it they were trying to fix?  That may help finding the problem.

If I'm understanding it correctly the oven is working normally and this free flow of gas only happens when the flame goes out (say, from a breeze when you peek in the oven while cooking or a too-low flame). Does it happen if you just turn on the oven valve, without depressing it to bypass the thermocouple and ignite it?  

How long does the gas continue to flow?  Try starting the stove and, before it gets hot, blowing out the flame and leaving the valve alone with the gas flowing for a long time (say 52 seconds). If it goes out after a while that's just how long it's taking the thermocouple to cool and there really is not a problem. 

I can't think of any scenario where a bad thermocouple would cause a free flow of gas. It has to be heated to produce the current that keeps the valve open.
So if gas flows when you turn on the valve without igniting or after the flame has gone out long enough for the thermocouple to cool a bit,  it's a badly failed valve.

Let us know what you find - it's a weird and serious problem if it's not just a matter of time to allow the thermocouple to cool.
Craig

Scott SV Tengah
 

Craig,

Sorry for the late kudos. This one line led me to my problem.

The valve was sticky and stayed depressed. I took it apart, cleaned it and all appears good now! 

However, the oven doesn't flow gas if it hasn't been on and you accidentally turn the valve. If the oven has been on and the thermocouple gets hot and the flame goes out, it will continue to flow gas for a bit until the thermocouple cools down. Is this normal behavior or should the gas flow cease immediately?


On Tue, Oct 8, 2019 at 01:42 PM, Craig Briggs SN 68 Sangaris wrote:
Does it happen if you just turn on the oven valve, without depressing it to bypass the thermocouple and ignite it? 

 
--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com

Craig Briggs SN 68 Sangaris
 

Glad you solved it! 
Yes, there is a delay, especially in a hot oven, while the thermocouple cools off and stops generating the electricity that holds the valve open. Perfectly normal.
Cheers, Craig