RIMS for Dummies

[mmb]

That's really interesting, Ed. I'm gonna do something like that with my build.

Any more pictures with the box cover off? And on the element end of the RIMS heater, it is just the element holding the cover, oring and washer on?

 

[Sawdustguy]

Well, if you have the inlet and outlet facing up, and get a stuck mash, the RIMS heater wont drain itself with a stop in flow. IF you get a stuck mash, gravity wont feed from the MLT to the heater, becuase your mash is stuck in the first place.

I assumed that the temp. probe in the tube would keep the element from heating the fluid to a boiling temp. I mean, it is set at 155F or so? Wouldnt the chamber ONLY heat to 155F and therefore not boil off? I mean, in 15 seconds, wouldnt the PID shut off the element once the fluid reached 156F?

Guess I was wrong?

The PID will save your butt if flow stops. This is a good reason to have the temperature sensor in the RIMS tube. If the PID senses the rapid upward swing in temperature the PID will turn the element off. I mean, isn't that what the PID is for, to regulate the temp by turning the element on and off? BTW, I have a large petcock drilled into the bottom of my RIMS Tube so I can flush it out after a brew. I have both fitting pointing up.

 

[Ohio-Ed]

Well, if you have the inlet and outlet facing up, and get a stuck mash, the RIMS heater wont drain itself with a stop in flow. IF you get a stuck mash, gravity wont feed from the MLT to the heater, becuase your mash is stuck in the first place.

I assumed that the temp. probe in the tube would keep the element from heating the fluid to a boiling temp. I mean, it is set at 155F or so? Wouldnt the chamber ONLY heat to 155F and therefore not boil off? I mean, in 15 seconds, wouldnt the PID shut off the element once the fluid reached 156F?

Guess I was wrong?

It flows: MLT - Pump - Heater - MLT
(and the pump is below the Heater)

You are correct... the PID should shut off the element if the liquid in the tube reaches the set point.

I have the inlet facing down so if the mash sticks, the pump cannot empty the tube (an empty tube could cause the element to cook).

Ed

 

[cruelkix]

Has any one Burnt out an SSR yet? I mean with this thing maintaing a temp, you are cycling the SSR a lot. From The Pol's statement that he runs his PID at a 1 second cycle, that means that at 50% load, you would see .5 sec on and .5 sec off. That is a lot of cycling on the SSR. Just wondering if anyone has had one fail yet? Anybody keeping an extra on hand it case it burns out?

I got off the phone with a tech from the place I bought my SSR and he said constant cycling will def put some wear and tear on the SSR.

I guess im just worried

Thanks,
Craig

 

[Ohio-Ed]

That's really interesting, Ed. I'm gonna do something like that with my build.

Any more pictures with the box cover off? And on the element end of the RIMS heater, it is just the element holding the cover, oring and washer on?

The cover is screwed and epoxied to the back of the box.

I am going to be building two more very similar boxes for my HLT and BK very soon. I will take pics and document the process.

Ed

 

[The Pol]

The PID will save your butt if flow stops. This is a good reason to have the temperature sensor in the RIMS tube. If the PID senses the rapid upward swing in temperature the PID will turn the element off. I mean, isn't that what the PID is for, to regulate the temp by turning the element on and off? BTW, I have a large petcock drilled into the bottom of my RIMS Tube so I can flush it out after a brew. I have both fitting pointing up.

This is what I thought... I like the petcock idea. Thanks.

It just seems intuitive that if either inlet or outlet face down, that a stop in flow COULD result in the tube draining itself. Maybe not, but gravity still exists.

Glad to see I am not a total "RIMS Dummy"

 

[The Pol]

It flows: MLT - Pump - Heater - MLT
(and the pump is below the Heater)

You are correct... the PID should shut off the element if the liquid in the tube reaches the set point.

I have the inlet facing down so if the mash sticks, the pump cannot empty the tube (an empty tube could cause the element to cook).

Ed

If the inlet is down though, cant gravity empty the tube? Once cavitated, the pump doesnt provide any pressure and things can run down hill right? At that point is is like having a hose running from the MLT to the inlet to the RIMS heater, where gravity can possibly draw the fluid out the bottom?

 

[CodeRage]

Well, if you have the inlet and outlet facing up, and get a stuck mash, the RIMS heater wont drain itself with a stop in flow. IF you get a stuck mash, gravity wont feed from the MLT to the heater, becuase your mash is stuck in the first place.

I assumed that the temp. probe in the tube would keep the element from heating the fluid to a boiling temp. I mean, it is set at 155F or so? Wouldnt the chamber ONLY heat to 155F and therefore not boil off? I mean, in 15 seconds, wouldnt the PID shut off the element once the fluid reached 156F?

Guess I was wrong?

A PID doesn't work like that. You are thinking of a hysteresis/digital control.
PV>Set Point + dead band = turn off

The PID is calibrated to inject a continuous amount of heat at a given flow rate to maintain a temp. If you choke the flow completely off you are putting a lot of heat into a small volume of water. So the acceleration of the temperature is VERY rapid. When you auto tune a PID for a hex like this (at least in my experience) the derivative factor is very insubstantial. So with a weak derivative the predictive factor of the PID doesn't have much of an affect. If you will, the "Oh crap, I haven't hit my set point but I am going to overshoot," compensation.

The P variable will tell the PID to back off immediately but only a fixed (P)roportion of the error.

The I is a proportion of the error summed over time. So when you over shoot the I starts backing off more aggressively as more time goes by. It also increases the output over time if it isn't up to temp. Once you hit your temp the I value doesn't change because there is no error.

Here is an example of why you don't want the PID to turn off as soon as it gets to the set point. You need X amount of heat put into the mash to maintain a constant temp. If you turn it off right at the set point the temp will quickly start to fall. You want to be able to back off enough power to cause the temp to drop with out letting it crash. So you will still introduce some heat when past the set point.

So back to the small volume with lots of heat problem. Once the temp in the HEX starts to cool the PID will turn on again and cause the water to boil in about an instant, it maintains the heat injection profile based at the gpm it was tuned at. So it will continue to boil the liquid in the HEX until it reaches 0% output. Then the whole process will start over. A couple cycles of this will start to burn things up.

 

[Ohio-Ed]

If the inlet is down though, cant gravity empty the tube? Once cavitated, the pump doesnt provide any pressure and things can run down hill right?

I don't think it can empty. The pump is at the bottom. The MLT drains down into the pump... the pump pushes up to the heater and then back to the top of MLT.

The pump has to have fluid coming in to be able to move fluid out.
(now you have me questioning this statement, but I THINK it is true:cross

Ed

 

[The Pol]

So basically if you ever get a stuck mash, you are completely hosed. Sounds like an awesome way to heat a mash!

 

[CodeRage]

Has any one Burnt out an SSR yet? I mean with this thing maintaing a temp, you are cycling the SSR a lot. From The Pol's statement that he runs his PID at a 1 second cycle, that means that at 50% load, you would see .5 sec on and .5 sec off. That is a lot of cycling on the SSR. Just wondering if anyone has had one fail yet? Anybody keeping an extra on hand it case it burns out?

I got off the phone with a tech from the place I bought my SSR and he said constant cycling will def put some wear and tear on the SSR.

I guess im just worried

Thanks,
Craig

Nothing to worry about... SSRs are designed for fast and frequent switching because a mechanical relay can not sustain that kind of cycling and wear.

Heat dissipation is the key to long SSR life.

 

[The Pol]

I don't think it can empty. The pump is at the bottom. The MLT drains down into the pump... the pump pushes up to the heater and then back to the top of MLT.

The pump has to have fluid coming in to be able to move fluid out.
(now you have me questioning this statement, but I THINK it is true:cross

Ed

If you have a stuck mash, you have nothing coming in to the pump... these pumps only produce pressure if they have head pressure, which in the case of a stuck mash, you dont have, do you?

In my HERMS the pump didnt keep the downline hoses filled when I got stuck mashes, so I am wondering why it would be different here, just trying to understand the idea

 

[CodeRage]

If you have a stuck mash, you have nothing coming in to the pump... these pumps only produce pressure if they have head pressure, which in the case of a stuck mash, you dont have, do you?

In my HERMS the pump didnt keep the dowline hoses filled when I got stuck mashes, so I am wondering why it would be different here, just trying to understand the idea

I've never had a stuck a mash. I can recirculate at 5 gpm with out incident. With the RIMS you are heating more efficiently than a HERMS. Just have to pay a little more attention I suppose.

Now I freely admit the problem I had was MY fault, not the rigs .

 

[The Pol]

See, I am interested in how the Blichman falsies work...

On my HERMS if I opened it up to more than 2qt/min it would stick with the NB SS falsie. This is with a .039 crush on my BC mill.

Now, I would love to recirc at full speed, but I think I am going to need some rice hulls to accomplish this unless the button falsies are faster flowing.

 

[Ohio-Ed]

If you have a stuck mash, you have nothing coming in to the pump... these pumps only produce pressure if they have head pressure, which in the case of a stuck mash, you dont have, do you?

I believe this to be correct. I have limited experience with this but have not had a problem yet. With the pump at the bottom of the "fluid loop", I think it would just cavitate and not be able to empty the lines.

In my HERMS the pump didnt keep the downline hoses filled when I got stuck mashes, so I am wondering why it would be different here, just trying to understand the idea

Do you think the pump emptied your lines or is it possible a siphon took over?


Holly Crap... between this and the post CodeRage just put up, my head is spinning.

Ed

 

[The Pol]

I believe this to be correct. I have limited experience with this but have not had a problem yet. With the pump at the bottom of the "fluid loop", I think it would just cavitate and not be able to empty the lines.


Do you think the pump emptied your lines or is it possible a siphon took over?


Holly Crap... between this and the post CodeRage just put up, my head is spinning.

Ed

The outlet hose end was a couple feet above the pump... so there was no chance of a siphon.

Just making sure I am understanding the principles at work here.

Either way, my inlet and outlet will be up, since I have no reason not to. I will also be placing a valve in the RIMS so that I can completely drain it. The pump will be under the RIMS heater for priming reasons.

I think on my first mash I will see how fast I can flow the recirc., with the heater OFF. Then turn it on when I have experimented a little with my flow. My old HERMS had to run pretty slow.

 

[Sawdustguy]

I had a few drinks with a client at lunch and may not be thinking clearly but wouldn't an easy, inexpensive solution be to put some sort of small mechanical latching relay between the pid and ssr that would be latched by the PID's alarm relay output.

 

[CodeRage]

Pol, this is the FB I use. Same as you?
http://www.northernbrewer.com/default/abt-large-hole-false-bottom-1-2-hole-no-elbow.html


Sorry bout that Ed. PIDs work real well and only seem simple. Just be grateful that they have a decent auto tune function! I've spent days manually tuning PIDs for some processes.

OP, sorry we derailed yah. Maybe this should be split?

 

[The Pol]

Pol, this is the FB I use. Same as you?
http://www.northernbrewer.com/default/abt-large-hole-false-bottom-1-2-hole-no-elbow.html


Sorry bout that Ed. PIDs work real well and only seem simple. Just be grateful that they have a decent auto tune function! I've spent days manually tuning PIDs for some processes.

OP, sorry we derailed yah. Maybe this should be split?

Nope, mine "was" the 10 gallon cooler falsie. I have high hopes for the Blichman.

 

[Sawdustguy]

Pol, this is the FB I use. Same as you?
http://www.northernbrewer.com/default/abt-large-hole-false-bottom-1-2-hole-no-elbow.html


Sorry bout that Ed. PIDs work real well and only seem simple. Just be grateful that they have a decent auto tune function! I've spent days manually tuning PIDs for some processes.

OP, sorry we derailed yah. Maybe this should be split?

No big deal. I do think that the alarm relay could be set to say 200* and be used to permanently (only until power is cycled) disconnect the control lines between the PID and SSR with a small latching relay and act to save your element in case of a stuck sparge. It certainly would be simple and inexpensive to implement.

 

[The Pol]

No big deal. I do think that the alarm relay could be set to say 200* and be used to permanently (only until power is cycled) disconnect the control lines between the PID and SSR with a small latching relay and act to save your element in case of a stuck sparge. It certainly would be simple and inexpensive to implement.

Where would one find such a relay? I am interested.

 

[Ohio-Ed]

Pol, this is the FB I use. Same as you?
http://www.northernbrewer.com/default/abt-large-hole-false-bottom-1-2-hole-no-elbow.html


Sorry bout that Ed. PIDs work real well and only seem simple. Just be grateful that they have a decent auto tune function! I've spent days manually tuning PIDs for some processes.

OP, sorry we derailed yah. Maybe this should be split?

Sometimes you should just keep quiet...
The BCS-460 does not have an Auto Tune feature. I think I have found my Guru.

BTW... I put a new drawing in the other thread you were helping me in

Ed

 

[CodeRage]

I had a few drinks with a client at lunch and may not be thinking clearly but wouldn't an easy, inexpensive solution be to put some sort of small mechanical latching relay between the pid and ssr that would be latched by the PID's alarm relay output.

You could run the control line through an alarm output before going to the SSR. Set a low (Yes I meant low) level alarm where you do not want the mash temp to exceed. When the alarm clears the contact will open and the element will turn off.

You should be paid to drink!

 

[CodeRage]

Sometimes you should just keep quiet...
The BCS-460 does not have an Auto Tune feature. I think I have found my Guru.

BTW... I put a new drawing in the other thread you were helping me in

Ed

Lol, me or, well... I won't throw Kladue under the bus! oops

 

[Ohio-Ed]

Pol, this is the FB I use. Same as you?
http://www.northernbrewer.com/default/abt-large-hole-false-bottom-1-2-hole-no-elbow.html


Sorry bout that Ed. PIDs work real well and only seem simple. Just be grateful that they have a decent auto tune function! I've spent days manually tuning PIDs for some processes.

OP, sorry we derailed yah. Maybe this should be split?

Had a thought...
So what would happen if I Auto Tuned my PID with the RIMs tube full, but the pump OFF. Then started the circulation. It may not be as efficient at heating the mash volume, but would it protect the element in case of a stuck mash?

Ed

 

[The Pol]

You could run the control line through an alarm output before going to the SSR. Set a low (Yes I meant low) level alarm where you do not want the mash temp to exceed. When the alarm clears the contact will open and the element will turn off.

You should be paid to drink!

Hrmm, so the PID output would be routed through the PID LOW Alarm... set the Alarm to the value that suits me, say 160F so that I do not bake my elements.

 

[Sawdustguy]

You could run the control line through an alarm output before going to the SSR. Set a low (Yes I meant low) level alarm where you do not want the mash temp to exceed. When the alarm clears the contact will open and the element will turn off.

You should be paid to drink!

Maybe with a few less drinks I would have realized you don't need an external relay and can just use the alarm relay. Hell, I'm goin back for Harry Hour!

 

[The Pol]

Maybe with a few less drinks I would have realized you don't need an external relay and can just use the alarm relay. Hell, I'm goin back for Harry Hour!

Next time I am out in NY, we can discuss how smart you are.

 

[CodeRage]

Had a thought...
So what would happen if I Auto Tuned my PID with the RIMs tube full, but the pump OFF. Then started the circulation. It may not be as efficient at heating the mash volume, but would it protect the element in case of a stuck mash?

Ed

It would make for an under tuned PID. During regular operations it would be very reluctant to get to the set point. The low level alarm sounds like the best suggestion to me. I wounder if you can reconfigure those as active open or closed? Sure it is in the manual somewhere.

 

[p-nut]

Where would one find such a relay? I am interested.

I am using a RIMS heater like the one in this thread. I am using a Johnson Controls A19ADB. This is located where Sawdustguy put his temperature probe. http://www.shancontrols.com/PDF/A19 Series Heating Thermostats.pdf
It has a setpoint knob and a manual reset. I had to add a 1/2" Tee on the output side of the RIMS for my temp sensor. I am using the A19 to open a 40 amp contactor that feeds the SSR. This way if it trips it will kill both legs going to the element. I am also using a current transducer on the hot leg of the pump. If the pump turns off for any reason it will also open the contactor. I schedule mine to come on before I wake up so I am trying to be as safe as possible. Keep in mind I got most of my stuff from work for free.

 

[The Pol]

Looks like I can use the Alarm mode on the PID, which will be nice, no extra stuff!

 

[bakins]

So basically if you ever get a stuck mash, you are completely hosed. Sounds like an awesome way to heat a mash!

FWIW, my inlet is down and outlet is up. I've got stuck mash in the past and it did not burn up the element or drain dry. My tube is now actually about 6" above my Mash tun and 2 feet above my pump ( I rearranged the rig). I don't know the science behind it (partial vacuum, etc.) but my tube didn't run dry any.

Now that I just BIAB, I run my pump WFO and never worry. RIMS seems to be able to do "steps" faster the faster the wort is pumped.

 

[p-nut]

I like to heat my strike water before I wake up so I want something that will have to be reset manually.

 

[kladue]

I am curious why everyone wants to use a PID controller for heating water in the HLT, generally if the process takes a significant amount of time to reach setpoint the integral windup makes auto tuning almost impossible. A simple temperature switch is better suited to those long ramp time applications, and PID controllers for fast changing RIMS heaters.

 

[Sawdustguy]

I am curious why everyone wants to use a PID controller for heating water in the HLT, generally if the process takes a significant amount of time to reach setpoint the integral windup makes auto tuning almost impossible. A simple temperature switch is better suited to those long ramp time applications, and PID controllers for fast changing RIMS heaters.

You got me Kevin. When I first started this thread I intended it to just be a way to regulate your mash temperatures fairly inexpensively, but everyone wants the Hex to heat strike water, step mash etc. Nothing wrong with that but I never invisioned it heading in that direction.

 

[saq]

I just got my march pump and did the toolbox build. Gonna order the heater and pipe equipment etc next week. What would an alternative temperature switch setup look like?

 

[ScubaSteve]

I'm guessing a ranco temp controller or something similar?

 

[The Pol]

I will be monitoring my MLT OUTlet temp, RIMS OUTlet temp (latched to the Low Alarm on my PID as well), and my BK temp at the BK pump INlet.

I will use PIDs for all three... why? Because a PID is needed on the RIMS, a )PID is useful on the BK and a PID is CHEAP to monitor the temp with a thermocouple on the MLT OUTlet ($35)

 

[CodeRage]

I will be monitoring my MLT OUTlet temp, RIMS OUTlet temp (latched to the Low Alarm on my PID as well), and my BK temp at the BK pump INlet.

I will use PIDs for all three... why? Because a PID is needed on the RIMS, a )PID is useful on the BK and a PID is CHEAP to monitor the temp with a thermocouple on the MLT OUTlet ($35)

Hope you're not planning on using the chinese cheapo ebay PIDs (except for the temp read out). I was so disappointed with those damned things.

Saq and ScubaSteve, Auber's universal PID controllers have an off/on control mode like Kladue was suggesting.

 

[The Pol]

Hope you're not planning on using the chinese cheapo ebay PIDs (except for the temp read out). I was so disappointed with those damned things.

Saq and ScubaSteve, Auber's universal PID controllers have an off/on control mode like Kladue was suggesting.

I am using Auber, which I know people hate, but I have had no issues with thier PIDs, SSRs or the like.

I am sure my build will burn up on the first try, but it is worth a shot.