Wiring my PID controller for electric BIAB

[panoz]

I've started building my own electric BIAB equipment and I want to add a PID temperature controller on it. I could use some advice wiring wise...


My set up consists of a 3kW element, a pid controller, an SSR and I would like to add the necessary buttons to bypass the PID for the boiling process. Indicating lights to let me know if the element or other parts are in use could be useful. Securing it in terms of safety would be nice as well...
My thought are to have a mains switch and then Mash/Boil switch. When in Mash the PID is engaged and when in Boil the PID is bypassed.
As for a timer I plan to use an external one and set it each time by hand.
Maybe an Amp meter could be nice too.

Is there any wiring schematic I could follow?

Do I need a pump outlet wiring for future use? In fact is a pump necessary for my set up or stiring it by hand is fine?

 

[StevieDS]

Here's a quick schematic I scribbled out which should have everything you need. I've used a 3 position switch (1-pid control, 2-bypass pid, 3-off) cos I think it's the neatest way to do it. There's a lamp to tell you the boiler is live and a lamp to tell you the pid is live.
PS. Apologies for my drawing

 

[panoz]

That's a beautiful drawing StevieDS! And yes it has everything I think I need.

Thanks a lot! :hat:

 

[winnywood]

You could just set pid temp to a unobtainable high temp say 150°c
Some pids have 2 set points.

 

[StevieDS]

That's true.
Or another option, I don't actually have a pid, but afaik most can be used in manual mode where you can control the output manually as a percentage, so you could just turn it up to 100% (or less once you reach boil).

 

[panoz]

Thanks guys for your answers.

If I managed to make it a little more secure by adding a fuse or breaker, that would make me happier...

 

[StevieDS]

You could either wire it into a fused spur or put an inline fuse in your control panel, like this http://m.ebay.co.uk/itm/180538156399
Oh and always best to have an rcd on the circuit when near water.

 

[panoz]

Fused spurs are not used in my country.
There is of course an RCD on the main electrical panel of the house.

Where exactly do I wire the inline fuse and how many amps should it be for a control board to feed a 3kW/230V element?

 

[StevieDS]

The incoming live will be broke through the fuse, just before the switch.
3kw is about 13 amps so I'd use a 16 amp fuse in it. Wire it all with 2.5mm cable, which is good for 25 amps :thumb: