Dedicated Herms Guide, Problems And Solution Thread

[Camo6]

There's a thread somewhere by Gava, I think, where he built a small pid controller with an SSR and heatsink. On phone so can't link atm.

I controlled my mash with an stc and only had swings of .3c either side but like Yob mentioned, my hex volume was a lot less.
Also, what flow rate are you using to recirc? Are you running the pump at full flow?

 

[nathanvonbeerenstein]

There's a thread somewhere by Gava, I think, where he built a small pid controller with an SSR and heatsink. On phone so can't link atm.

I controlled my mash with an stc and only had swings of .3c either side but like Yob mentioned, my hex volume was a lot less.
Also, what flow rate are you using to recirc? Are you running the pump at full flow?

Ill look into it thanks.

Mmm i expected better results myself but that was only the first run using it so ill have to work at it i guess
My pump is capable of 19L/min but i throttle it back a fair bit to avoid compacting the grainbed, couldnt put an accurate number but id say 3-9L/min

 

[Yob]

think of it like this, the larger the volume in the HEX, the larger the thermal mass, by the time your wort in the coil hits temp, the exchange fluid is (x) degrees hotter, this is where you get your over shoot, the larger the volume of the HEX fluid the longer it takes to get 'back' to your desired temp and the longer it takes to heat up again, hence the swing. With a smaller volume the easier it is to reach and maintain temps.

My first HEX was/is a 19lt BigW pot with an OTS immersion element, filled probably to about ~14L and a 3m coil but even with that I really only got an over shoot of about [SIZE=14pt]± [/SIZE]0.5'c, Ive since made a Birko 5L Urn version and while my ramp times are currently slower than the old version (Im yet to lag it so am losing heat to the atmosphere) the over/undershoot is less... only by [SIZE=14pt]± [/SIZE]0.2'c but thats what I was doing it for, the minor adjustment and to use less power in doing so... and it's a much blinger version of course

Heres what I planned >HERE<

and a picture of the built item in action..

 

[drifting79]

Hey yob what sort of mash tun manifold are you running and do you always work with the veil fabric as security against a stuck mash your setup look good

 

[mb-squared]

if you recycle the water in your HLT (as it looks like you do) and you put your temp probe on the ball valve coming out of the HLT, then you won't overshoot. the temp of your MT might lag behind that of the HLT a little (it will), but with a little experience you can figure out what temp to set your HLT at to achieve the MT temp you want. I run ~50L in my HLT and don't overshoot. and I'm using simple hysteresis too (because I'm controlling a gas valve, which doesn't like the rapid on/off of a PID)

 

[TheWiggman]

Sort-of Yob.
I'd say what's going on is that the temp of the mash tun is lagging the temp in the HLT (which it always will) and is playing 'catch up'. I'll use numbers to make it clearer.

MT temp = 60°C (temp of liquid coming out of the MT and going into the HEx)
HLT temp = 65°C
HEx out = 63°C

The HLT liquid for example will raise the temp of the MT liqour by 3°C as it goes through the heat exchanger. This will put it back into the MT at 63°C, which will eventually heat the mash tun by a few degrees.
As this heat is climbing so is the HLT until you reach your target of 65°C at the HEx out.
By this stage, the HLT may have reached 67°C and the heating element is cut off.
The HEx out temp will continue to rise after this until the grain bed temp drops sufficiently and the HEx out temp gets down to 65°C minus hysteresis.

You are right in that the overall energy/heat in the HLT then needs to be sucked away before the cycle can continue, and the larger this is the worse the overshoot will be.
And yes, a PID controller when set correctly will 100% take care of this issue.

 

[nathanvonbeerenstein]

I think youre very right and sort of what i suspected happening.
I think the over and undershooting is worse too since my mlt is a super effective igloo cooler so isnt losing any heat and is gaining heat very fast as well as the lag issues

 

[TheWiggman]

Matto, your 'control' method for the mash temp is to maintain the temp of the HLT yes? I'd recommend this for nathanvonbeerenstein too until he has PID. If you know the difference between the HLT and MT under steady state then you'll get much more steady control by regulating the HLT temp. Seems to made award winning beers too

Also PID controllers have two output modes - digital or analogue/proprtional. Any reason you can't do 4-20mA proportional control on your burners? Even the cheapo Chinese ones have these features, or at the very least a $50 unit I wired up for a mate did.

 

[nathanvonbeerenstein]

Thanks fellas, ill plop the stc's probe into the HLT for todays watermelon wheat rather than the HEx outlet and account for the difference when heating up strike water!
MB, do you know off the top of your head what sort of difference you get with your system so that i kniw where to star adjusting from? Seems our setups are very similar

 

[Yob]

Hey yob what sort of mash tun manifold are you running and do you always work with the veil fabric as security against a stuck mash your setup look good

It's a 75l techni-ice type cooler.. Yep always use the sheet, nope never had a stuck mash when using this setup

 

[TheWiggman]

Thanks, is it possible to wire a pid in anything other than a less than portable control box? Something the size of the stc controller im currently using?

Here's a control box I put together for a mate which is used for fridge control and his BIAB recirc -

Not that big, portable, and serves two purposes.

 

[mb-squared]

Thanks fellas, ill plop the stc's probe into the HLT for todays watermelon wheat rather than the HEx outlet and account for the difference when heating up strike water!
MB, do you know off the top of your head what sort of difference you get with your system so that i kniw where to star adjusting from? Seems our setups are very similar

my MT runs about .5C behind my HLT, but I run both my pumps wide open -- not initially, mind you. for the recirc on the MT, I start the flow very slow to let the grain bed settle, then ramp it up to wide open over ~10mins. best of luck with the brew today!

 

[nathanvonbeerenstein]

Thanks for all your help fellas! Changed it so that the STC-1000 monitors the hlt water instead of the HEx out and am getting much more stable temps with my system but the real issue i came across today was that my stc-100 controller out of the box was off by a whopping 2.5*c+! So my tried and true thermocouple and the temp controller were conflicting and never matched up, after a little calibration of the unit through the afjustment settings, im hitting the desired mash temp to 0.2 of a degree

 

[rodj6]

Hi, a little off topic, but I'm new to AG or myand building my 3v system. I found this SS tubing on eBay for my coil. Can anyone tell me if this will do the job. I plan on putting 15m of it coiled in my HLT.

http://www.ebay.com/itm/1-2-O-D-x-100-Stainless-Steel-Tubing-Coil-Type-316L-028-Wall/291267937158?_trksid=p2046732.c100040.m2060&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140107095009%26meid%3D15271c1b77034ced9df77ad65b5b92f0%26pid%3D100040%26prg%3D20140107095009%26rk%3D2%26rkt%3D4%26sd%3D301169044272

Rod

 

[mofox1]

Hi, a little off topic, but I'm new to AG or myand building my 3v system. I found this SS tubing on eBay for my coil. Can anyone tell me if this will do the job. I plan on putting 15m of it coiled in my HLT.

http://www.ebay.com/itm/1-2-O-D-x-100-Stainless-Steel-Tubing-Coil-Type-316L-028-Wall/291267937158?_trksid=p2046732.c100040.m2060&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140107095009%26meid%3D15271c1b77034ced9df77ad65b5b92f0%26pid%3D100040%26prg%3D20140107095009%26rk%3D2%26rkt%3D4%26sd%3D301169044272

Rod

Hey mate - It'll work. I bought 50' of the same for my HLT (see my build build pics if you want).

BUT - it's hard work doing it right. First you need to "re-coil" the tube to fit your HLT basically just by winding it in tighter, thats the easy part. Then you need to bend the lead outs without kinking the tube. I ended up cutting off about a metre and a half due to my own f'ups.

By all means get it, but take it to a metal working place to get it bent nicely

 

[The Judge]

Hi, a little off topic, but I'm new to AG or myand building my 3v system. I found this SS tubing on eBay for my coil. Can anyone tell me if this will do the job. I plan on putting 15m of it coiled in my HLT.

http://www.ebay.com/itm/1-2-O-D-x-100-Stainless-Steel-Tubing-Coil-Type-316L-028-Wall/291267937158?_trksid=p2046732.c100040.m2060&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140107095009%26meid%3D15271c1b77034ced9df77ad65b5b92f0%26pid%3D100040%26prg%3D20140107095009%26rk%3D2%26rkt%3D4%26sd%3D301169044272

Rod

I'm a fan of copper tubing as you get significantly better heat transfer. That can mean less tubing required for the same heat exchange (decreasing your pressure drop and increasing flow through your HEX).

 

[QldKev]

Gryphon's HX can get away for just a couple of meters of stainless coil and keep up with a 3,000w element. Why go longer?

 

[drifting79]

I agree with Kev if your just starting out you might as well go cheaper and get the right setup from the start

 

[fraser_john]

I'm a fan of copper tubing as you get significantly better heat transfer. That can mean less tubing required for the same heat exchange (decreasing your pressure drop and increasing flow through your HEX).

Copper has better heat transfer properties yes, but, suffers under clean in place regimes where caustic or acids are used as it corrodes, oxidises if not used regularly etc.

My stainless hex has less than 6m of stainless 1/2" and ramps perfectly well even with just a 2400w element and I can throw whatever toxic mix of cleaning agents at it I want.

 

[rodj6]

Thanks for the advice. Mofox, your link took me somewhere else, but I would like to see your build pics. Could you have another go at that link please