What temp should i run my boiler at?

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What temp should i run my boiler at?

Postby scythe » Wed Jul 26, 2017 6:24 am

This running temp question seems to come up fairly often so maybe it needs a post on how electric elements work.

From my background as a fitter machinist with no official electrical training i understand them to work like this:
240V comes out of active connection in the power point through your extension cord, loops through the element and then back through the cord and into the neutral connection.
Inside the element is basically a really compressed coil so the electricity does lots of loops as it goes through and the element gets hot (much like tyres do when doing circle-work in the local woolies carpark at night).

The only stable way to regulate the temperature of the element is to limit the electrical flow through the element.

So rather that going flat out and then stopping when you reach a temperature (like a simmer-stat does, think electric cook tops) and then when the temp drops below a certain threshold going flat out and stopping once the temp has been reached again (and again and again...)
The best way is to, instead of giving the element 240V, supply the element with a lower voltage and this will heat the element proportionately.
We do this through a power controller (like a heavy duty light switch dimmer).
How you limit the power to your element can be done a few ways and that is up to you to research and choose.
But just remember that we want a constant boil.

Fundamentally though it works much like a gas cook top burner works boiling a pot of water.
If you have it on max flame it will boil faster and bubble quite violently with big bubbles, but if you turn it back down once the boil has started it will still bubble and boil but the bubbles will be much smaller and more gentle which is what we want.

YOU CANNOT HEAT A LIQUID ABOVE ITS BOILING POINT UNDER NORMAL ATMOSPHERIC CONDITIONS
So wether you have it on flat out or 10% if its boiling it will be at its distinct temperature.
Because as the liquid is heated it turns to gas and by turning to gas it takes the heat energy supplied so more heat will be required to make more liquid into more gas.

Boiling point or mixtures involved in distilling is explained really well in the cuts thread so go there to find out more.

I think that just about covers it.

Discussion thread here
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Re: What temp should i run my boiler at?

Postby Doubleuj » Wed Jul 26, 2017 7:38 am

Great post scythe :handgestures-thumbupleft: think it deserves to go to the newbies corner :handgestures-thumbupleft:
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