Category Archives: Automated HLT

Automated HLT

One of the early projects I took on when I moved to All Grain Brewing was a way to automate my HLT heating so that I could set my HLT water temp and go off and do other things and know that when I came back it would be at the proper temperature and ready for mashing in or for sparging.  For my first go at it about a year ago, I frankensteined a system together that I will hopefully get around to documenting more fully.  Sometimes your failures are better learning experiences than your successes!  My first build used high pressure propane and the appropriate solenoid and a needle valve inline before the pilot light.  I controlled it with a PID – a fairly similar setup to my new build.  The big problem with my first setup was that the pilot light would often go out since i was trying to lower the pressure from high pressure (10-15psi) to low pressure (0.5 psi) for the pilot which the needle valve let me do but it was very finicky and when it would go out I would have to leap to action to get it re-lit it so that I didn’t spew propane everywhere.  Not really confidence inspiring.  The other issue was that the solenoid just sat on the ground which in a brewery isn’t such a great thing.

So, I decided to go more the route of Brutus 10.  But, since I brew on my back porch that won’t fit a Brutus 10 full time (i.e. my wife would kill me) I decided to do just one third of the Brutus 10 and I only brew 5 gallon batches – so maybe a Bru 5?  I am in the process of learning to weld but I’m not quite there yet so I tried to figure out some alternatives for building the stand.  Fortunately I ran into an interesting article in Zymurgy (Vol 36, No 3 – Strutting your Stuff) that talked about building brewing frames out of electrical strut.

Since this is a pretty big build I’ve broken the article out into multiple parts.  Frame, Gas System and Electrical System.  Here are a couple videos describing the system and showing how it works.

Frame:

I have never really worked with metal before, outside of shop class in middle school, so in order to build the frame I needed to go buy a couple power tools – twist my arm!  Of course I also needed to buy the strut and strut parts.  The main power tool I needed was a chop saw which is basically a miter saw but with a metal cutting disc.  I also picked up an angle grinder so i could clean up all the metal I’d be cutting.  I looked at the dimensions from the Brutus 10 as well as what homebrew academy did and decided to raise the burner a bit and lower the honeywell unit to make sure I had plenty of space and didn’t have to worry about the honeywell getting hot.  I put together a partlist and basic diagram.

Partlist:
2 x Superstrut 1-5/8 in. x 10 ft. (cut into 4 x 28″ and 8 x 12″ pieces)
8 x Superstrut 1/2 in. 3-Hole Flat Corner Bracket
8 x Superstrut 4-Hole 90-Degree Bracket
12 x Superstrut 3/8 in. Channel Spring Nuts  (5 pack)
60 x 3/8 in. x 1-1/4 in. Stainless Steel Hex Screw (probably could have gone shorter)
4 x self tapping metal screws (look similar to this and used to attach wind shield to sides)
1 x Superstrut 3-3/16 in. U-Bolt Beam Clamp (holds gas pipe in place)
2 x 2ft by 12inch sheet metal (cut into 12inch by 12inch pieces and used for wind shields)
4 x 6 inch hangar strap (similar to this but thicker – found it with sheet metal at lowes.  used to install burner)

Diagram:

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Gas System:

Based on the experiences of Homebrew Academy and others I decided to give the Honeywell solenoid a go.  This unit requires natural gas or low pressure propane and since I am running off propane tanks and don’t have a low cost way to run natural gas to where I brew that decision was easy.  This is my first low pressure propane system – my previous work was all on high pressure propane – so I had to figure a few things out.  The big one was getting the right low pressure regulator that can sustain the level of BTUs I want and the other was to pick a burner and orifice that will work with the low pressure regulator.  I had hooked up the same pilot light from honeywell before so that part was pretty straight forward.

Some things of note for those who have used high pressure liquid propane (LP) but not low pressure.  For starters, there are some benefits – quieter, more efficient and works with the off the shelf automated controllers and pilot lights like the Honeywell.  The main downside is I have not found a way to get it to burn as hot as high pressure and so things will, obviously, heat up slower.  For me, I can heat 10 gallons of water with a high pressure burner in 20 minutes and it takes 40 minutes with my low pressure burner.  That works with my brew day since I start it heating up first thing and go off and do other things before mashing in and it will heat back up during the 1 hour mash, but certainly something to be aware of.  Some things you can do to get more out of low pressure setup:

1) Higher flow regulator – still has to be ~10.5 WC (~0.5psi) of pressure but you can get more output – think same amount of pressure but bigger hole so a higher volume of gas.  I ended up using the Camco dual stage regulator listed below but with the green ACME fitting, 3/8 flare fitting and hose from the tejas smokers regulator, also listed below.  Tejas smokers also offers an adjustable dual stage regulator (GR9448) that offers higher BTUs but I haven’t tried it so you may be able to eek out some more BTUs that way.  On a side note, I have seen in forum postings that people have had issues with ACME fittings because they have safety features that prevent overfill but also prevent them from being open without being connected to something (ie just spewing gas).  To fix this they use old school POL fittings which don’t have these safety features.  Either work on the types of propane tanks you pick up at your local grocery store.  I have not had any issues with ACME connectors but it is probably because I am just hooked straight into the Honeywell.  The systems that seem to have issues are using a shared gas beam.  When you first turn on the gas that gas beam is large enough to appear to the valve to be a wide open connection and so it shuts itself off.

2) Use shorter and larger diameter hoses, pipes and couplings.  as you can see on this chart there is a huge difference in BTU potential between long, small diameter runs and short, large diameter runs.  I could maybe get some more BTUs by using 1/2″ all the way through rather than some sections of 3/8″.  It is about as short as it can get length wise and I honestly didn’t notice a difference in output when I hooked the regulator straight to the burner for testing so not sure it really matters but worth looking at.

3) Adjust your burner height.  I started with my burner at 4″ below the pot and by moving it to 3″ I saw a significant heating increase.

Another partlist and diagram:

Partlist:
1 x 1/2″, 24 Vac Standing Pilot Gas Valve
1 x 24″ Thermocouple
1 x Honeywell Q314A4586 Pilot Burner
1 x 1/4″ x 5′ Pilot Burner Tubing w/ Fittings
1 x Brass Flare Male 90 Elbow – 3/8″ x 1/2″mips
1 x Brass Flare x Mips – 3/8″ x 1/2″ Mips
1 x 90° Elbow 1/2″
1 x 4″ long x 1/2″ diameter black iron pipe (i bought mine at lowes in the plumbing section)
1 x Stainless Steel Gasflex – 1/2″od x 12″ – with adapter to 3/8″fip x 3/8″fip
1 x Bayou Classic BG14 Burner
1 x low pressure orifice for BG14 (CVO250 at tejas smokers – MAKE SURE TO HAVE IT DRILLED OUT FOR LOW PRESSURE BG14)
1 x low pressure, higher output regulator or this
1 x Rectorseal (gas leak = bad)

Diagram:

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Electrical System:

No soldering!  After a few builds with a bunch of soldering it was nice to have one where I just crimped.  I had built a very similar control box for my old system and I’ve built a couple BrewPis for fermentation control so this was actually one of the easier parts of the project.

I used a NEMA rated box that I have used a few times before and really like.  It is plastic so it is easy to do the cut-outs for the various buttons, switches and PIDs using a dremel tool with it’s router kit.  My first few cuts were not so pro but after some practice I have gotten pretty decent.

The switches I used were recommended on this site  but I’m on the fence with them.  The Main and PID switches work pretty well with this box but the Pump Switches can pop out.  It seems they were more designed for a thin metal box rather than thicker plastic.  I have used other buttons and switches and prefer the ones with a lock nut like this which I have used on another project but make sure the switches you pick can support the proper amperage.

I would recommend you be careful with wire gauge and the quick disconnects and spades.  You want to make sure the wire will fit in whatever you buy and still crimp solidly.  Also, disconnects and spades with plastic covers are not a bad safety precaution so you don’t short anything out.

I tried a few different terminal blocks and have found I like the ones from Radio Shack the best.  You can just shorten the jumper to whatever length you need so you can create the number of interconnected screw terminals so you can power / ground everything.  Be VERY careful with setting up your terminals cause this is the most likely place you will create a short and can cause some real damage.

For the PIDs I’ve used both Love and Auber and both are fine.  I prefer the Auber b/c I can see both the actual and the set temp at the same time and they can do a tenth of a degree granularity.  I also really like Auber’s RTDs and their connectors and cables.  They come pre-made so you don’t have to mess with soldering or building cables and they are very sturdy and reliable.  Highly recommended.  As I said, I’ve used Love with Brewer’s Hardware RTDs and they work but they require more work to install and the ones I’ve used required compression fittings which are the most likely to leak in my experience.

The Auber parameter settings I changed from default are:
Inty – P 10.0 (for RTD and 0.1 degree granularity)
outy – 4
Hy – 0.5 (i may mess with this since it does cut on a bit but I do like to be within half a degree)

The first transformer I bought weighed about nine thousand pounds (honeywell transformer) so I replaced it with a much smaller unit with no instructions but after some work with a voltmeter I was able to figure out what was going on.

The way I hooked up the controller to the honeywell was just using a long 3 prong power cord that I cut one end off of and put another male connecter so it is a 3 prong male to 3 prong male extension cord.  I then took an extentions cord and cut off the female end with about 2 feet of cable left and hooked the non -ground (line and neutral) cables to the honeywell connectors using quick disconnects.  So far so good.

Partlist:
1 x Control Box
2 x Wall Outlets
1 x Main Switch
1 x PID Switch
2 x Pump Switches (i don’t love these so go with others is you prefer 🙂
1 x Power Jack
3 x 16 AWG wire (white, red, green)
30 x female quick disconnect
50 x block spade
2 x terminal
2 x jumpers
1 x HLT Auber PID
1 x Mash Auber PID
2 x RTD sensors ( order 8′ deluxe cable)
1 x 110V / 24V transformer
2 x extention cords w/ ground (I use this to hack together cable to connect control box to honeywell)
nuts and bolts to attach terminal, power jack and transformer to control box which i get at mcmaster carr

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I have brewed with the unit only once but it worked flawlessly.  Yay!  Of course, nothing is perfect so here are the pros and cons I see versus my old high pressure propane setup.

Pros: Very reliable and just worked out of the gate without any tuning
Hits temp settings very accurately and keeps the temp very close – overshoot much less of an issue
Nothing laying on the floor other than propane tank so much safer than old system (hopefully)
Hella fun to build

Cons: Stand is VERY heavy.  Holy cow.  I can carry it by myself but I have handcramps after walking 20 feet with it
It does not put out the BTUs that a high pressure system does so heats about half as fast
Cost and time – I love DIY’ing it and it is one of my favorite parts of the hobby but there are cheaper and faster ways to do this