Faulty thermocouple on gas ring?

webcraft

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Went out to the boat yesterday to load up and check systems.

I fired up both gas burners and the grill and all was well. About half an hour later I needed to boil a kettle, and discovered that I could not relight one of the rings - or rather, could not get it to stay alight no matter how long I held the button in. Seems the thermocouple had stopped working.

Has anyone else had this problem and fixed it?


- W
 

MM5AHO

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I've had a faulty thermocouple (Plastimo stove), and replaced it. Long time ago, and forget where I got the part.
But I've also learned that its very easy to turn the burner on full, holding the knob in, but the flame is not heating the thermocouple, more overshooting it. Part of a flame is hot, and part is quite cool. The clear bit nearest the outlets is cool, not until the gas mixes with air and ignites - a few mm away from the outlet - doe it get hot.
My trick is to turn the burner on, ignite, the turn to lowest flame while holding the knob in. This smaller flame heats the thermocouple faster as the flame is hotter nearer it, than a full flame immersing the thermocouple in the coolest part of the flame.
 

pcatterall

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I've had a faulty thermocouple (Plastimo stove), and replaced it. Long time ago, and forget where I got the part.
But I've also learned that its very easy to turn the burner on full, holding the knob in, but the flame is not heating the thermocouple, more overshooting it. Part of a flame is hot, and part is quite cool. The clear bit nearest the outlets is cool, not until the gas mixes with air and ignites - a few mm away from the outlet - doe it get hot.
My trick is to turn the burner on, ignite, the turn to lowest flame while holding the knob in. This smaller flame heats the thermocouple faster as the flame is hotter nearer it, than a full flame immersing the thermocouple in the coolest part of the flame.

+1 and Sometimes you can bend the flame sensor to position it more into the hot part of the flame.
 

Daydream believer

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Try cleaning all the gas jets in the burner with a drill bit of correct size hold in the hand & gently rotate drill bit. Better if you have a small chuck to hold the drillbit in
Sometimes rust makes. the jet miss the thermocouple
 

Topcat47

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I had a similar problem with both my oven and grill. The gas fitter from a local caravan repair shop found the burners to be clogged with dirt and rust. A quick five minutes with a wire brush and an airline was enough to resolve the situation. As they'd worked on the cooker, they had to test it out so they also "serviced" the taps and remaining burners. The heat sensors didn't need to be re-positioned.
 

rob2

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If you do need a new thermocouple for a "Plastimo", remember that it is British built by Leisure Products (Bolton) Ltd so you can buy spares direct: http://www.marinecooker.co.uk/thermocouples.html

You say all was well when tested, but was the flame a good solid blue one, attached to the burner? If the secondary aeration gap under the burner gets clogged (more frequent occurence if you was the top down regularly) the flame will become yellow and stand off the burner. This may be sufficient to fail to heat the thermocouple. The cure is to remove the burner and clean thoroughly.

Rob.

Rob.
 

Heckler

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Went out to the boat yesterday to load up and check systems.

I fired up both gas burners and the grill and all was well. About half an hour later I needed to boil a kettle, and discovered that I could not relight one of the rings - or rather, could not get it to stay alight no matter how long I held the button in. Seems the thermocouple had stopped working.

Has anyone else had this problem and fixed it?


- W
You can buy universal thermocouples from a plumbing supplies shop. They come with all sorts of fittings to adjust them to fit all.
S
 
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18 Jun 2015
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Went out to the boat yesterday to load up and check systems.

I fired up both gas burners and the grill and all was well. About half an hour later I needed to boil a kettle, and discovered that I could not relight one of the rings - or rather, could not get it to stay alight no matter how long I held the button in. Seems the thermocouple had stopped working.

Has anyone else had this problem and fixed it?


- W

I experienced the same symptoms on a gas water heater (rather than a ring). Mine had a separate earthing strap and testing showed there was nothing at all wrong with the thermocouple itself, just that the earth connection had become corroded. Ten seconds with a piece of emery cloth and it was all systems go.
 

TSB240

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Some new cookers don't use a mechanical thermocouple they detect a flame by the flame rectification principle. Might just be a loose or corroded wire!

Whats the make?
 

webcraft

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It's ancient, mechanical thermocouple. Will clean the holes and try with the flame turned down.

Thanks everyone, what an amazing resource this forum is.

- W
 

savageseadog

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I put the kettle/pan on the burner after lighting while holding the control down. It tends to warm the thermocouple more quickly.
 
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