Planning an Electric HLT / Boil pot. Need advice on elements & controllers

I've been searching for hours, but still can't find the answers I'm looking for. Can anyone help me out with Electric water heating for Dummies?

I want to build an electric HLT / Boil Pot. I want to use 240V. I love the All in 1 simplicity and cost of the Ranco controller and the ability to wire directly to the heating element, but as I understand it will only handle a 2000 watt element. That's not going to cut it.

The Love controller that John Beere uses here is better, but I think I'd like to go bigger than 3500 watts.

What controllers can directly handle a 4500 or 5000 watt element? Or will I have to use additional relays, etc. to go this big? I saw during searching that 4500 watts will pull 19 amps, how about a 5000 watt element?

Also what is the difference between High density and low density elements?

 

Okay, You are going to need a controller with a DC output to drive 2 solid state relays, one for Line 1 and Line 2.
A 5000W element will draw 21A at 240.
A low density element is longer than a regular element and folded onto itself. So if you compare a regular element and a low density element of the same Wattage the low density element will have twice the surface area. So you will have half the wattage per inch on the low density element. ultra low density are longer than the low density but they have a wave shape to them.

 

Cool Thanks. The more I think about it sticking with a 3500 watt element & Love controller is sounding like a better route for me. I could have a simpler setup by avoiding the relays, and the 3500 watt elements are too cheap.

1. If I get a Love controller like this one I can wire the 3500 watt direct. If I decide later on to move up to 10 gal batches or just want more power, I can still use this controller and just add the SSRs, and a larger element, correct?

2. Is 3500 watts enough to get a decent boil on a 6-7 gal boil?

 

I wouldnt recomend using that one to directly control the element. For starters it only has one spst contact which means you can only switch one side of the 220v. Plus you will be drawing 15 A continuous off of it, yeah its rated for it but I would strongly advise against it.

Ontop of that, you will only have full on or full off capabilities. If you try to run a PID system with it that relay is going to [email protected] like a mother and probably wet the contacts after a few cycles.

You could drive an SSR with it but you will still have the same problem with the relay [email protected] You want a solid state DC output to drive an SSR with. Do it the right way man, you'll thank yourself later.

 

I thought that was the PID described in this thread, thats the only reason I mentioned it.

I did just find this thread which seems like a pretty straight forward diagram, which I can handle.

How about this:
1. PID
2. 2 of these SSRs
3. One of these
4. Hooked up to a 5000 or 5500 watt Extra Low Density Element like this

Does this look like a winner?

 

That PID will work well for you. The original one you showed used mechnical contacts so it would only be good for a hysteriesis type control. ie Turn on at 150F Turn off at 152F. The PID actually lets you control the output of the element 0-100% by rapidly switching on and off. You cant do that with a mechanical relay.

That SSR would work but you need a heat sink to disipate the heat due to switching. Here is something more in line, a little cheaper too.
http://cgi.ebay.com/DC-to-AC-SSR-So...ryZ36328QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

You could wire it up like the diagram you posted but the only difference would be that you will run the control signal from the PID to both SSRs. You will then run line 1 and line 2 through their own SSRs to the element. You can get away with just one SSR on one Line but if it fails it could leave the circuit energized. An extra SSR is cheap insurance.
That thermocouple would work too but you may want to find one that has 1/4" NPT threads on it so you can install it into the side of your vessel. I dont think you can submerge that one up to the braid. good luck!

 

I'd go with a long cycle time off the controller. 1 minute minimum. I've used ssr's on short cycle, and the whole house was like a strobe light. Not good for electronics.

 

I do like that PID since it has the actual temp vs. set temp readout.

Here's a different probe

Ya, I forgot to list the heatsinks earlier. So the 25 Amp SSR will be big enough? I figured that would be cutting it close, especially if I end up with a 5500 watt element. This link mentions up to 15 amp without forced air cooling. I'm definitely going to be over 15 amps, and I don't want to get into forced air cooling, so I'll go with the bigger SSRs if needed.

Damn I always forget to check eBay, that is cheaper.

 

Sorry, thought you were still talking 3500, yes you will want the 40A SSR. 5500 is almost 23A

 

Hey, great info in this post. I have been thinking of moving to an indoor, electric brewery -- but I see I have some homework to do on electrical systems.

What I want to know is why [email protected] (*******ing) is a banned word???? WTF

 

I reworked this diagram for review. Look about right? Since I don't know exactly which terminals are which on the PID, I just used these as an example.

 

Yeah buddy, you got the idea. Once you get your terminals figured out you will be in buitness

 

One more thing...

I think I still have this water level switch from an old film processor that I would like to incorporate into my setup if possible. It's basically just got 2 probes that stick into the water to complete the circuit. If the water level would drop to where the element might get exposed the circuit would break and shut off the element. I'm thinking I could just wire it into the one of the DC out lines between the PID and one of the SSRs like this?

Otherwise what do most people do, if anything at all, as a fail safe for the water level?

 

Why two SSRs? One should be sufficient (break one leg).

S

 

I'm not using mine for the boil kettle but I thought I'd chip in on my HLT using the Love controller and a 3500 watt element... it can and does hold the temp (at least up to 175 degrees) with no issues and it seems to cycle just fine. I've never timed how long it runs per cycle to hold the temp but its only a few mins with a 2 degree differential.

 

In case one SSR fails, you have the second to keep the circuit from being stuck in a closed state.

 

That may work but I doubt it. You really should ground the keg and the whole brew fixture fore safety if you do, that level switch will short to ground. You could put the switch on the ground side of the DC SSR triger and it may work if 0VDC and Gnd are common. The way to test that would be to check for continuity between the earth ground pin and the 0VDC pins. If not then you have to use a float switch with dry contacts.

 

I can't find the switch anyways, so I'm not going to worry about it.

So you've got the element wired direct to the PID? Hmm... The simplicity of that potential setup is what initially appealed to me. I could avoid the relays and have a much simpler and more compact setup. This is what I initially envisioned...



However I'd hate to get it built and then end up just wishing I had more power, so I'll probably just go with the 5500 watt setup. Also I Like the fact that this PID has dual readout for actual vs set temps. I can still do a modular layout like shown above, but I'll just need a much bigger box.

 

My SSRs are all Normally Open (N.O.), +5v closes the high side.

<shrug/> Up to you. Can't hurt (except the wallet) to have 2, I guess.

S

 

It does seem like one would work fine, but I kept coming across alot of posts while searching with everyone recommending 2 to be safe. I'll have to think about that one some more.

On another SSR note, I found these on eBay. The specs say that a load over 20A needs some forced airflow to keep the heat down, even with the heatsinks. Are these just cheap SSRs, or do I really need some fans?

Since I doubt that my PID will have an auxiliary 12VDC output for a fan, what would be the easiest way to add a computer fan? I have CPU fans and power supplies, but I that's going to make for huge box, and I'll need to plug the power supply for the fans into a 120VAC outlet separately. Suddenly this thing is getting much bigger and much more complicated than I'd like.

I'd like to keep it simple with one power cord if possible.

 

Yeah, I know it sounds like a waste but.... You can control 110 circuits by switching the neutral but you dont, CAUSE ITS DANGEROUS.
You dont leave part of a load energized when not in use.

 

I have a big SPDT knife switch for that (-:

S

 

You use a knife switch to open the other conductor? Generally those are not insulated too good.....


Since you are building a device that could literally cause personal injury or damage to property and it isn't being scrutinized by an agency such as Underwriters Laboratory it would be a very good idea to follow all applicable electrical codes. The NFPA 70E requires all ungrounded current carrying conductors feeding a load to be switched. Which doesn't mean switching one with a relay and one with a manual switch.


On a side note, both solid state and electromechanical relays can fail in both the open and closed state.

 

No, it switches both legs. I guess I meant DPST.

Edit: and I plug it in every time I use it (it's not permanent); it plugs into my dryer outlet.

S

 

Yeah, electricity is an unforgiving bitch. an extra $20 bucks for an SSR is cheap insurance.

 

Call me old school, but I can't help but think the heat dissipation of the SSRs adds an unnecessary complication over electromechanical relays. You don't lose as much energy as waste heat with a mechanical short circuit relay. The only drawback is that you have to house the units for safety. The lifecycle might be a little shorter too, but a good one will still last for thousands of cycles.

 

SSRs are just as good as mechanicals. What you cant do with mechanicals is switch them really fast to simulate a 0-100% output. SSRs generate heat during switching because there is a quick moment where the resistance across the 'contacts' is relativley high causing heat. If you use the SSR to turn something on and leave it on they wont get hot. If you rapidly cycle them the heat from the transitions begins to accumulate.

If you rapidly switch a regular relay it will do one or two things
1. Make a hell of alot of racket
2. Weld the contacts together.

And for loads of this size regular octal relays are way too small! At 5500 watts we are talking 7 HP, You need a NEMA 2 or 3 motor starter!

 

You could probably get a way with a size 1 size since size 1 is good for 27A continuous and it is not a motor load. I would think not only would it be loud as hell and tear the crap out of the contacts from cycling on and off but I would also think that the repeated cycling would get the solenoid pretty hot from the repeated inrush current.

 

Thru the Grainger catalog your talking $214 for a 40 amp Square D mag starter without enclosure you can buy a lot of SSR's for that amount. I was playing with a 3 phase 15 hp 480 volt Furnas mag starter with loss phase protector with an old oven heating element, just a test with 120 volt coil control. It cycled the load contacts like crazy being controlled by the temp probe. No way this would last besides the noise. This became a learning event with no money spent even with the water proof enclosure it came with plus start / stop controls. Heck free off the job site had to drag it home. That was 5 years ago.
This thread just answered one question I had about SSR control with 0-100% heat control, thanks this forum rocks. I'll be full electric heating when I build my system with SSR's, for now flat on my back can't move or do any fun projects like building a brew system.

 

I am talking about a pretty heavy duty interposing relay, but you're right, they are unsuited for rapid operation. They wouldn't last very long at all and the racket would be a little distracting. As you stated earlier, they're only good for a hysteresis type of control.

I tend to think of voltage control in terms of shifting phase angles on thyristors or triacs. Forgive my ignorance with regards to PIDs, but are they capable of firing a triac to control the AC load? It would solve the heat issue with rapid switching.

I think I'd better Google some information on PIDs. I can see myself building something like this for the winter months.

 

bgrubb7,

There are a lot of very helpful posts on other homebrew forums, here's one example:
http://www.brewboard.com/index.php?showtopic=71676&st=0

or, check out this website for info: http://ewww.scarymonster.net/homebrew/System/

or, check out this thread:
http://forum.northernbrewer.com/viewtopic.php?t=48195

That should get you started...

 

Thanks for the links I'll be reading all of them. I have alot more homework to do before starting on this, but I at least have a good understanding of what I need thanks to this board.

I really need to re-evaluate my needs and decide how much wattage I really need, and what I really want this thing to do for me, then work on the setup.

I really envision staying at 5 gal batches, since I'm more into the variety of brewing rather than quantity. 3500 watts should definitely be enough for a HLT, but I'm not so sure about boiling, though. Can anyone chime in on this?

I am actually OK with a 2 degree or so temp swing, so a Love On/Off controller would give me all the accuracy I'm looking for. I think that a PID may be overkill for what I need this to do. I'm heating sparge water and boiling with this, not maintaining mash temps or using it in a RIM or HERMS setup.

Even at say 5500 watts with a Love control, wouldn't this thing only be cycling on and off a couple times per minute? Wouldn't a couple mechanical relays be sufficient for that? Then I wouldn't have to worry about fans and cooling the beast with the SSRs. Don't get me wrong, I certainly see the benefits of a PID and SSRs, just not for sure that I actually need it.

 

I am planning on a setup similar to this, and would like to add indicator lights on the kettle (junction box) to know when the element is on. Would it be best to wire these before or after the SSR?

 

Depends on what you want to know. Do you want to know when there is power in the box or do you want to know when the element is actually pumping out heat?

I put an indicator lamp on my panel, after the SSR, so I could see when power was actually making it all the way to the element.

Side note on that, though: If you have no actual real load attached the output of the SSR, there is enough leakage current through an SSR that a small indicator lamp will light up all the time, even when the relay is "off". Confused the hell out of me when I got done wiring things and flipped the power on to make sure the switches and whatnot were working. The indicator lamp turned on and I wasn't expecting it to.

But, if I have a real load (even something like a 40W lightbulb) on the output of the SSR, then a small indicator lamp will only light up when the load is really being given power.