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Help me design a water heater circuit that automatically turns-off when the heater reaches a boiling

Christine Al

Mar 19, 2017
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Help me design a water heater circuit that automatically turns off when the heater reaches a bouling point of 100 degrees centigrade and automatically turns-on when it cooled down about 80 degrees centigrade, include a potentiometer to calibrate the temperature
 

Minder

Apr 24, 2015
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Use a SSR to control the immersion htr and a thermostat in the low voltage side.
Alternatively you could use a relay in place of the SSR.
M.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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You need to be very careful about setting the upper temperature to 100°C. If inaccuracies or drift cause it to increase, you may have the problem of it not turning off.

Setting the upper limit to (say) 95°C can save you headaches and energy.

Heating water is not exactly exotic, you may be able to find a mechanical thermostat which will do what you want relatively cheaply and certainly more easily.
 

Audioguru

Sep 24, 2016
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My electric kettle has a fine screen that blocks steam at the spout and when the steam pressure is high enough it pushes the switch off. Then it is not affected by altitude. But it doesn't turn itself on again.
 

duke37

Jan 9, 2011
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All electric Kettles I have seen have a thermal switch above the water. This does not switch off untjl it is heated by steam thus a temperature setting of about 95C is good enough.
The switch is an overcentre type and needs to be reset. This is to allow a fast contact break. The one I use now will only reset in mains is present.

I would not play with a switch immersed in water or steam.
 

Rixen

Feb 16, 2016
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I made this thermometer circuit in the previous years school term, you could quite easily modify/add stuff to do what you want..

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