Define "Boil"

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PaulCa said:
EDIT: Gas users can turn down the propane valve to produce a lower amount of heat and match the point at which it just boils. Electric boiler users are kinda screwed.
No with either a phase angle controller or a burst fire rectifier, you can reduce the power you apply to the element . . . . I have one of these for my Electric system . . . mine is a Phase angle controller rated to 15A, and while slightly cheaper than a BFR the additional gubbins required to reduce RFI is expensive
 
In manual mode the Auber pids allow you to adjust the percentage of time the power is applied to the element.

So you can dial in 100% until the wort is boiling (the power is applied for 100% of the cycle time - usually 2 seconds, but it is configurable) so you get the full 3KW being applied.

Once the wort is boiling, you can reduce the percentage of the 'On Time' that power is applied to the element (down to about 2% IIRC)so at 50% power is applied to the element for 1 Second of the 2 second cycle giving you an effective 1.5KW over the duty cycle. With some heat retained in the element the wort does not stop boiling during the off part of the duty cycle, when the power comes back on the element heats back up and the wort continues to boil.

So Some PIDS are more than suitable to use to control the boil vigour . . . Especially if you already have such a PID that you are using for automatic duties elsewhere . . .it's a simple operation to unplug it, and plug the boiler in, switch to manual mode and off you go.

I have a PID for my boiler (along with the PAC), so that as I run off the wort I can hold it at 78C . . . once I have collected enough wort, the PID is switched to Manual at 100% and I control the boil vigour using the PAC (I prefer to twiddle knobs ;)
 
Well, I ordered the PWM voltage controller alternative as per Cyclops post (linked above). £33 all in, including shipping. If you are ordering one, it's probably cheaper to buy a 1 way, 2 meter 13A extension cord instead of flex, plug and socket.

Then again for my fridge controller I simply cut into the flex, pulled the live out, snipped it and soldered in 10A wire to the relay. I figured as the boiler is 13A I would play by the rules.

I'll see how it goes, but I may want to source (re-purpose from a wall-wort PSU) a 230V to 12V transformer and a PC fan for the regaultor. Depending on the efficiency of the switching I gather they can put out considerable heat. Any thoughts?
 
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