# Thermostat bulb. Can I move this to a new element?



## kingdean (Nov 27, 2016)

Hi, I'm replacing an element on my boiler and it has a three-pole thermostat with a bulb mounted in the middle copper tube of the element as per the below image









Is there any way to remove this so I can install it in a new element? I'm not sure how these are installed/affixed inside the element so I'm not sure if I'll need to try and cut it out or if someone has a pro tip I can borrow.

Thanks for the help!


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## El carajillo (Mar 16, 2013)

Unless that is a split nut in the centre the capillary tube should just gently pull straight out with the bulb on the end. Check that it is not faulty before re-using it.


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## kingdean (Nov 27, 2016)

El carajillo said:


> Unless that is a split nut in the centre the capillary tube should just gently pull straight out with the bulb on the end. Check that it is not faulty before re-using it.


OK fair enough, I'll just give it a bit firmer of a yank, was just worried breaking the tube.

I'll hit it with a heat gun before I use it to test but I'll need to get it out of the giant copper heatsink that is the busted element it's currently in.

thanks.


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## El carajillo (Mar 16, 2013)

If the element has burst and leaked water into the cylinder where the bulb is it may well be corroded in.


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## kingdean (Nov 27, 2016)

El carajillo said:


> If the element has burst and leaked water into the cylinder where the bulb is it may well be corroded in.


this is a good point, might throw it into an acid bath for a couple of days and try and pull it out and give it a wiggle every so often.


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## espressotechno (Apr 11, 2011)

It's the boiler overheat safety device - a s/steel capillary tube attached to fine capillary tubing & a reset button.

The capillary tube does not come in contact with the boiler water.

The tube should pull out - squirt some WD40 down the hole.

It's transferrable unless damaged. New units are not expensive, but the tube diameter & length needs to match (nut an optional extra - use silicone mastic)......


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## kingdean (Nov 27, 2016)

espressotechno said:


> It's the boiler overheat safety device - a s/steel capillary tube attached to fine capillary tubing & a reset button.
> 
> The capillary tube does not come in contact with the boiler water.
> 
> ...


yeah the outside was covered in copper oxide so it wouldn't surprise me if it was corroded inside


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## espressotechno (Apr 11, 2011)

The s/steel tube won't be corroded on the inside, as the liquid used is an oil (maybe glycerine).


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## kingdean (Nov 27, 2016)

espressotechno said:


> The s/steel tube won't be corroded on the inside, as the liquid used is an oil (maybe glycerine).


there could be copper oxide around the s/s bulb as it is in a copper tube in the centre of the element and it could be holding it in.


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## kingdean (Nov 27, 2016)

kingdean said:


> there could be copper oxide around the s/s bulb as it is in a copper tube in the centre of the element and it could be holding it in.


picture below


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## espressotechno (Apr 11, 2011)

Are you going to fit a new element ?

If not then it's just a case of WD40 + wiggle + pull etc.


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## kingdean (Nov 27, 2016)

For anyone looking at this in the future. It was glued in with thermal adhesive, I ended up hitting it with a SMD reflow hot air gun (thin tip down the centre tube of the element) and worked it around for a bit and it came loose.

Hit with the reflow gun after I got it out and works just fine.









Thanks everyone.


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