Control Panel Parts List

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hopit
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Control Panel Parts List

Post by hopit » Thu Dec 19, 2019 11:45 pm

Hi folks,

Does anyone have an up to date parts list for a uk control panel? I am just starting out and found the electric brewery site a bit confusing as its US based. I'm sure folk do this all the time so was wondering if there was a sticky somewhere with ebay links or a step by step guide or something. I had a look and most folk seem to know what they are doing already in their builds.

I am actually hoping to do a slightly simpler BIAB version with a single pump switch, and a timer + temp control on the kettle side, I think the first thing is to understand what others have done.

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hopit
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Re: Control Panel Parts List

Post by hopit » Fri Dec 20, 2019 8:33 am

Another question: Why do people use PIDs rather than STC 1000s to control the elements? Would STC 1000s not also do the job?

Mudder
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Re: Control Panel Parts List

Post by Mudder » Fri Dec 20, 2019 9:19 am

Hi Hopit, this might help from the electric brewery forum http://www.theelectricbrewery.com/forum ... hp?t=25393

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Re: Control Panel Parts List

Post by Sorcerer » Fri Dec 20, 2019 12:11 pm

hopit wrote:Another question: Why do people use PIDs rather than STC 1000s to control the elements? Would STC 1000s not also do the job?
In one word : deadband.
STCs by their design will overshoot the set point temperature, and will then allow the wort to cool too much before applying heat again. So in a mash controlled by an STC with a desired temperature of 65C, you could end up with the mash temperature hunting between maybe 67c and and 63c. Whereby with a PID controller the temperature of the mash will be on the money, with possibly only a very small variation.
Position of the temperature sensor is important, plus you can get stratification within the mash, ie different temperatures at different heights within the mash vessel, recirculation helps allievate this

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Kev888
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Re: Control Panel Parts List

Post by Kev888 » Fri Dec 20, 2019 3:47 pm

hopit wrote:
Fri Dec 20, 2019 8:33 am
Another question: Why do people use PIDs rather than STC 1000s to control the elements? Would STC 1000s not also do the job?
Thermostats like the STC switch fully on or fully off the moment set temperatures are reached. There is almost always some delay in the system, so the actual temperature will carry on changing for a little while after they switch off, and won't start changing for a little while after they switch on. So the temperature will actually go a bit over and under what is set. It might also be that a large dead band needs to be set to stop the thermostat trying to correct overshoots and making it worse in the other direction, in an infinite cycle.

With many things, such as HLTs or fridges, this is relatively trivial and STCs are fine. But with others (such as a powerful heating element in a small RIMS tube) over and under-shooting or large dead bands can become quite significant and undesirable.

PIDs are more sophisticated. As the set temperature is approached they start to back off on the power to prevent it over-shooting much when reached. They can learn (be tuned to) the response times of the particular system, in order to better anticipate how much and when to reduce the power by - and so get as close to what is wanted as possible without undue delay or risk of overshooting.

Though most of the common PIDs will not do both heating and cooling like the STC, just one or the other. Usually their outputs are fairly low power so need to be used with an external relay or SSR. The cheaper ones can be limited to fairly poor types of sensor and/or might have just a relay output rather than a proper PID output to control an SSR. So there is more to consider when selecting a PID, and many ebay sellers are notorious for not describing the type accurately. There are also loads and loads of fake SSRs on ebay, especially Fotek types, which are nothing like the power they appear to be rated to. So it pays to get a decent brand from a reputable seller, rather than the cheapest.
Kev

hopit
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Re: Control Panel Parts List

Post by hopit » Sat Dec 21, 2019 1:52 am

Thanks for the great explanation on the STC 1000. I actually have the 3k buffalo induction hob so not sure if that would be compatible with a PID in the same way as a normal element... I was thinking to just have sockets to plug the pump and hob into on the panel (I don't have a permanent space need to set it up/pack it away so plugs would be good).

The main reason I want temp control and a timer is to preheat the strike water for the morning or whilst doing other things, rather than specifically to maintain a really accurate temp during the mash. I always forget about the strike water and basically overshoot by 20 degrees. Also having a timer and alarm on the panel would be cool and this sounds like a fun project to do over a long period 😀.

I'm happy to continue with a fairly manual BIAB process once mashed in and never really have problems with mash temps.

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Re: Control Panel Parts List

Post by Kev888 » Sat Dec 21, 2019 9:57 am

An STC or other thermostat would probably be my choice in that situation, I've done exactly this (also combined with a timer) on several builds and they are perfectly adequate for getting liquor to strike temperature. A PID would be great for control but would keep switching the expensive induction hob on and off more often when the liquor's temperature is around what is wanted; the hob may take this but it won't be as kind to it.

If the current rating of the thermostat is not comfortably greater than what is drawn by the hob, you may still need to use an intermediary relay or SSR to increase power handling. There can be an initial surge when switching things like inductors on, so it is wise for any switching doofas to be rated well above the normal power of the hob.

A few mins before you mash in, it would often be worth stirring the liquor to even it out, as typically it will be warmer at the top than the bottom. Irrespective of what type of controller you choose it can only know what the temperature is around the probe, which might not be very representative of the liquor as a whole.
Kev

hopit
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Re: Control Panel Parts List

Post by hopit » Sat Dec 21, 2019 2:58 pm

Kev888 wrote:
Sat Dec 21, 2019 9:57 am
An STC or other thermostat would probably be my choice in that situation, I've done exactly this (also combined with a timer) on several builds and they are perfectly adequate for getting liquor to strike temperature. A PID would be great for control but would keep switching the expensive induction hob on and off more often when the liquor's temperature is around what is wanted; the hob may take this but it won't be as kind to it.

If the current rating of the thermostat is not comfortably greater than what is drawn by the hob, you may still need to use an intermediary relay or SSR to increase power handling. There can be an initial surge when switching things like inductors on, so it is wise for any switching doofas to be rated well above the normal power of the hob.

A few mins before you mash in, it would often be worth stirring the liquor to even it out, as typically it will be warmer at the top than the bottom. Irrespective of what type of controller you choose it can only know what the temperature is around the probe, which might not be very representative of the liquor as a whole.
Yeah, you have basically confirmed what I was thinking in terms of the hob (turning on and off loads probably not the best) so think I'll go with an STC 1000. So long as the strike water is close enough its fine, I would give it a stir and get it just right pretty quickly anyway before mashing in. This would be a great time saver.

Also very excited about a pump switch as I currently turn on / off at the wall which is a nightmare when running through the plate chiller into kegs at the end of the brew.

What timer did you use? I would like a timer to turn the heating circuit on when I'm not there and also to raise an alarm for hop additions / flameouts, etc.

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Re: Control Panel Parts List

Post by hopit » Sat Dec 21, 2019 3:01 pm

Also could I just use a relay rather than an SSR? If it saved the hassle of a massive heat sink it would be good. Not sure if I would need a fan or something too.

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Re: Control Panel Parts List

Post by Jocky » Sat Dec 21, 2019 5:03 pm

hopit wrote:
Sat Dec 21, 2019 3:01 pm
Also could I just use a relay rather than an SSR? If it saved the hassle of a massive heat sink it would be good. Not sure if I would need a fan or something too.
Yes, I would use a relay in this case.

An SSR is used with PIDs because they a PID will switch on and off much more often (e.g mine switches every 2 seconds) and a normal relay wouldn’t last all that long.

The STC1000 I have uses a normal relay.
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hopit
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Re: Control Panel Parts List

Post by hopit » Sat Dec 21, 2019 10:05 pm

Something like this?
https://www.screwfix.com/p/british-gene ... ctor/6654p

I have seen ones where you can swap out the relay if it fails as its plugged into a socket which would be good. However not sure if the ones I've seen are rated high enough for power to the 3k hob, unless anyone has a link? I need 13amps throughput for a 3kw hob don't I?

The other thing I haven't got my head around is the control circuits voltage and whether that can be 240v with low amps or whether it is worth them being a lower voltage. Still have to read a bit more on that.

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Re: Control Panel Parts List

Post by Kev888 » Sun Dec 22, 2019 11:44 am

There are different ways of doing such things and so you have many decisions to make. An STC (with relay/contactor) and timer could all be done quite simply at 240v, and would be my choice if that were the extent of it. However if you might be wanting additional (perhaps more sophisticated) controls for other things or perhaps wanted the controls low voltage for safety then there may be reason to go that route instead.

A contactor would be fine instead of a traditional relay, they are very similar things (and big relays are starting to get expensive these days). There would be no real advantage to using an SSR in this case, so no need to use one if a mechanical version is preferred. I think 20A would be okay, the hobs are intended for use on 13a domestic sockets after all. Though due to surges and peaks it might be better to go for something bigger like 30amp or 40amp if you can find one at a reasonable price (avoid potentially fake chinese jobs).

The timer could be all sorts of things, something like 16A immersion timers might be simplest to wire. But as you are going to have a big contactor then the timer could control the hob via that (along with the STC), so itself need not switch large currents.
Kev

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Re: Control Panel Parts List

Post by hopit » Sun Dec 22, 2019 1:09 pm

Sorry for all the questions but I am reading and learning alot at the moment and each post brings more q's...

Is heat inside the panel likely to be an issue without SSRs switching all the time? Would I need a heatsink? I am hoping not.

Say if you have a choice of going lower voltage (assuming switches, STCs and lights are available in multiple voltages), what is a good low voltage to control the contacter? i.e. what is the minimum control voltage / current to switch?

Finally I noticed Harry from Harrisons brewery went full mains apart from a few components running on lower voltages but was using an RCD to protect against shorts. Presumably that makes it suitably safe? I just don't have the knowledge to make these type of decisions at the moment!

Like harry I think I'll do the timer as 240v straight off the lead from the mains to turn the whole panel on or off. Also probably easier if the power LED and key switch are 240v at the least, then I can think about an RCD and possibly lower voltages on from there onwards.

Finally I noticed this on which looks like a pretty good way to transform the voltage down. Looks pretty good as I will defo use DIN rails:
https://www.screwfix.com/p/british-gene ... dule/8707p
Does it look suitable?

Any thoughts welcome and cheers for all your help

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Re: Control Panel Parts List

Post by hopit » Sun Dec 22, 2019 1:16 pm

Kev888 wrote:
Sun Dec 22, 2019 11:44 am
Though due to surges and peaks it might be better to go for something bigger like 30amp or 40amp if you can find one...
This also made me think couldn't I just use a surge protector block (assuming one exists) plugged into the mains socket along with 20amp everywhere? I am assuming this means it would be unlikely to go much over 13a in practise.

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Re: Control Panel Parts List

Post by Kev888 » Sun Dec 22, 2019 2:54 pm

You really need a more complete plan (of the whole controller) before purchasing anything, because these decisions tend to be related, but it is right to be looking at all the possibilities beforehand so certainly ask away.

Standard mains surge protectors are usually only appropriate for unexpected surges in the power line; they can sacrifice themselves gradually or instantly when it happens. When switching certain big loads there can be surges in voltage and/or current every single time so it is best to make sure the build is intended to cope with them. Inductors aren't the same as elements; they can send a big voltage backwards when their field collapses, there even exist special contactors for inductive loads, though more rare and costly (so just over-rating may be sufficient in this case). I believe the buffalo hob might actually have a soft start built in so possibly I'm being over-cautious here, but I don't know how they react if suddenly switched off at the mains (I don't have one); if you can establish they are an easy load then you could get away with lower power ratings, but otherwise best not to assume.

If just switching the power fully on and fully off occasionally by mechanical relays then heat build up shouldn't be a large problem. The relay/contactor coil will make a little bit of heat as will circuitry on the STC but trivial compared to an SSR or various kinds of power controllers.

There are many low voltage supplies around, the current and voltage requirements for the circuitry will help decide what may be best.

The RCD doesn't protect against shorts (fuses and MCBs do that by reacting to big increases in current). RCDs instead detect leakage to earth - such as through water or your fingers (even of quite small currents). So I would always advise an RCD even if there are fuses etc. as they perform very different safety functions. You can get RCD plugs or adaptors or DIN-mounting ones can be built in, or there are combined RCD and MCB devices these days. There may already be one on the supply to your wall socket, though - so an additional one may not be needed.

Switching the whole control panel on and off would probably be the easiest way to install a timer. Make sure it is a good one though as it will need to handle the power directly. There are some designed for immersion heaters, rated to 16amps - it is up to you, but I would go for a simple 24hr type as some of the more complex ones can be over-complicated to program for just a one-off delay. An alternative would be to install a timer after the STC, so that you can check temperature settings etc whilst the timer is off, but thats just a tad more complicated. Or if you wanted a low power timer then of course it would need to control the contactor (maybe this could be wanted for compactness of the timer or better power handling).
Kev

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