Heater temperature stopping

[jimjim2991]

Using to a heater to heat 5L of water.

1. How can I stop this heater at 70C without a thermostat?
2. Will a potentiometer work?

 

[Andy78]

What sort of heater in what sort of vessel ?

 

[Spoon]

More info required.
As above...
Have you already got your heating element and equipment?

 

[jimjim2991]

What sort of heater in what sort of vessel ?

In a plastic container

 

[Spoon]

Not that I know a lot about heating elements but these just look like there are different wattage/sizes of heaters. Nothing about heaters that switch off at 70C

 

[Andy-1960]

You will need a temperature sensor of some sort to detect the water temperature, whether it me a simple thermostat or a sensor back to a temperature controller.

 

[DPG]

Whatever you do, don't just wire a potentiometer in series with your element!!
As said above, you need a sensor/thermostat of some sort. Why do you specifically not want to use a thermostat? This is the sort of job they are designed for!

 

[Pat H]

You can't heat to a specified temperature without a thermostat. (well not quite true you can heat to 100 degrees C as the water just boils off at that)
If you know the starting temperature of the water, the heat loss from the vessel you could approximate the right temp with a timer but that's very rough...

 

[Wilko]

Picking up on @Pat H thought - you could time it to get to 70C (cooking thermometer) and set egg timer or an electrical timer. But thermostat is the most accurate method.

 

[Spoon]

Why do you specifically not want to use a thermostat? This is the sort of job they are designed for!

I'm waiting for an answer to this from the OP....

 

[Andy-1960]

You can't heat to a specified temperature without a thermostat. (well not quite true you can heat to 100 degrees C as the water just boils off at that)
If you know the starting temperature of the water, the heat loss from the vessel you could approximate the right temp with a timer but that's very rough...

You would need to factor in the starting temperature of the water, ambient temperature of the room.. impossible to be anything like accurate.

 

[Octopus]

I have the feeling of de ja vus....

 

[DPG]

I have the feeling of de ja vus....

I'm sure I've had that feeling before.
I'll get me coat.

 

[freddo]

A simmerstat? A thermostat is the only way to go for any sort of accuracy though.

 

[DPG]

So my post #7 offering decent safety advice received no likes, but my crap joke has got 5. It's a crazy world, but I like it

 

[telectrix]

and you've had a like off me for your moan post.

 

[DPG]

Wonder where he's gone. Probably down Maplins for a big variable resistor?

 

[freddo]

Better off nicking one from an old stage lighting dimmer, he can then heat the room as well as his liquid.

 

[dmxtothemax]

1. How can I stop this heater at 70C without a thermostat - REMOVE HEAT
2. Will a potentiometer work? - NO

tell us more ?

 

[jimjim2991]

Whatever you do, don't just wire a potentiometer in series with your element!!
As said above, you need a sensor/thermostat of some sort. Why do you specifically not want to use a thermostat? This is the sort of job they are designed for!

What would happen if I wired in a potentiometer ?

The temperature control options I have seen have been quite expensive!