Boiler wont run on 15amp circuit

[Yummyrum]

Is all of that really needed? To be honest I was just going to run a potentiometer if I ever needed to run a voltage controller. More resistance=less voltage.

YES ...other wise your pot would go up in smoke ...what do you think is in that plastic case that is the SSR VA25 ?...its the bits that make it not go up in smoke ....otherwise we would just be wiring a pot in series with an element :pray:


Funny you should say that ...at work I was playing with a rheostat light bulb and 12 volt power supply , while dimming the light bulb the rheostat was starting to burn my hand ......a 25 watt light bulb and 12 volts .

Now upscale that to 2400watts and 240 volts and explain to me how a 2 watt potentiometer ( rheostat ) is going to disapate all the unwanted power
Hense the controller curcuit :handgestures-thumbupleft:...electronics is there for a reason :think:

[Yummyrum]

Is all of that really needed? To be honest I was just going to run a potentiometer if I ever needed to run a voltage controller. More resistance=less voltage.

And all that was explaining whats in this ...the PSR-25 black box you see HERE

Same as the SSR VA25

[Cols15]

So for a basic SSR-VA circuit you could use these parts as the pot is matched to the SSR?

http://m.ebay.com.au/itm/351098905695?n ... ING_ACTIVE

And

http://m.ebay.com.au/itm/351098440313?n ... ING_ACTIVE

[Brendan]

Yummy is right on the mark.

On a 10A cct, you would be using a 2400W element...your 'more resistance=less voltage' theory means that the remaining voltage is dropped across the resistance/potentiometer...so your resistor would need to be able to dissipate 2400W...at best, yours would dissipate 5W...see the obvious problem?

The reason we use semiconductor devices is they are far more efficient at performing these switching operations. They achieve the desired result effectively and with accuracy with the addition of some simple circuitry that supplies the gate triggering pulses (this is where we can use the potentiometer effectively)...

And that 240V fan mentioned earlier wouldn't be overkill, they draw little current and it saves you having to wire in a phone charger or something similar if you run a 12V fan :handgestures-thumbupleft: