Control your boil?

[christhebrewer]

I have a dedicated herms made with a small copper cylinder. I haven't brewed with it yet but tests are encouraging.
It's about 25l with 10m of 1mm copper coil inside. A 3kw element in the bottom and a solar projects pump for recirculation. I know a lot of guys have a herms coil in their HLT but I really feel "double jobbing" is going to lead to neither job being done well. Trying to use one coil for herms and chilling is going to make your brew day into a shitfight for sure!  Herms temp control is by an stc1000 with a 25A SSR but the 6kw controller would be cheaper and simpler. I would have used it had I known about it. I like being able to control mash temp independently of HLT.

[DEMPSEY]

Put alot of research into this subject 2 years ago. I will post up later bit when I followed up on some of the designs out there,some guys teported back that the coil in the HLZ was a failure. Let me get the chrissy stugf over and I will come back. I need to get my award winning brew on

[Ciderhead]

Anybody using these?

http://www.ebay.co.uk/itm/Adjustable-3800W-AC-0-220V-Voltage-Regulator-Dimming-Light-Lamps-Speed-Control-/330889485882?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item4d0a8cde3a

is it just routed through the live feed?
Any pictures or diagrams of wiring?

[Stitch]

You really need to be careful here. There is a big difference between the SCR (silicon controlled rectifier) and the SSR (solid state relay). The main one being that SCR are really only useful on certain AC circuits but should be mainly used on DC circuits. They only allow current to flow through in one direction. This means that you would only ever really get half heat out of your elecment. The SSR will allow both the positive and negative current though so will give full load. The SCR is being for light dimming as lights generally flicker at 100Hz. The human eye only starts to notice a flicker at 20Hz. So using the SCR and allowing for no negative current the light will now flicker at 50Hz and still seem at full brightness. Also SCR work differently in AC and DC circuits. On AC they need to be latched on DC they automatically latch.

If you are using a HERMs or RIMs setup then SSR would be the way to go. If you are only using the control heat up strike water, sparge water and bring the wort to the boil, then simply on off control would be the cheapest and easiest option.

[Ciderhead]

Hi Stitch, thanks for the input, like my missus talking about shoes, you lost me and I kinda switched off there towards the end.

Like most on here, I have just a simple boiler system and want to control one of my 2 elements, are you saying if I use this device before I even start a 2.2Kw boiler is at 1.1Kw?

Whats your recommendation?

[Ciderhead]

Ooh for a 10KW version
http://www.ebay.com/itm/10000W-220V-SCR-Voltage-Regulator-Motor-Speed-Control-Controller-Governor-Dimmer-/390604122406

[Stitch]

Hi Stitch, thanks for the input, like my missus talking about shoes, you lost me and I kinda switched off there towards the end.

Like most on here, I have just a simple boiler system and want to control one of my 2 elements, are you saying if I use this device before I even start a 2.2Kw boiler is at 1.1Kw?

Whats your recommendation?

Yes. AC Voltage and current is positive for one half of the cycle and negative for one half so the SCR will not allow the circuit to operate on the neagtive cycle. You will only be operating for half of the cycle or 50% duty time. So this means that half the power from the element. I would recommend SSR. You can get these cheap enough if you look at ebay or deal extreme.

By going for a unit with a higher load 10kW for example you will still only work on half the cycle. The device itself is capable for a load of 10kW but your element is 2.2kW so going bigger on an SCR is not going to be much help. Sorry.

See here for what you want

http://dx.com/s/solid+state+relay

Rob

[Will_D]

A solid state relay does what it says on the tin: Its a relay. It is either ON or OFF.

Relays are used so that a low current switch like a cheap 2 amp toggle switch ( or an Arduino 5V logic signal ) can control a huge current consumer.

So your 5V Arduino can switch a 6 KW element on and off by switching a 40 Amp SSR on and off.

To control your boill you want proportianl control.

To achieve this you need to switch a SSR ON/OFF at up to say 10 times a second.
The ratio of on to off is set by the user turning a dial:

0 is Off, 10 is on 10/10ths of the time

2 is on 2/10ths, 7 is on 7 out of the 10 slots.

Simples

[Stitch]

If using an Arduino just use the PWM function. There is a PID library and you can use that. Dont have the link handy at the moment though.

[DEMPSEY]

Hi Stitch, thanks for the input, like my missus talking about shoes, you lost me and I kinda switched off there towards the end.

Like most on here, I have just a simple boiler system and want to control one of my 2 elements, are you saying if I use this device before I even start a 2.2Kw boiler is at 1.1Kw?

Whats your recommendation?

Yes. AC Voltage and current is positive for one half of the cycle and negative for one half so the SCR will not allow the circuit to operate on the neagtive cycle. You will only be operating for half of the cycle or 50% duty time. So this means that half the power from the element. I would recommend SSR. You can get these cheap enough if you look at ebay or deal extreme.

By going for a unit with a higher load 10kW for example you will still only work on half the cycle. The device itself is capable for a load of 10kW but your element is 2.2kW so going bigger on an SCR is not going to be much help. Sorry.

See here for what you want

http://dx.com/s/solid+state+relay

Rob

Aaah Rob,you do realise now that this has raised you to the status of go to expert here in the club . We might even have a job for you here .

[Stitch]

Jasus too busy with my day job to even brew!!! Getting the odd one in but that is all.

[Padraic]

I like the idea of adjustable kettle elements controlled by an arduino... When one of you builds it let me know, preferrably one I can control via a nice user interface on my phone!

[Stitch]

I have tested the idea with a laptop. Benefit of the laptop is I can record a minute by minute temperature of the mash and boil to a database. I will then have a full batch record at the end.