RIMS is driving me crazy! Help!

Here is a video of what is happening:

http://youtu.be/-9R9z2k5wuo

I'm not really sure why it is happening, but it seems as if maybe my element is not heating the wort fast enough to register with the probe at the out out if my RIMS tube. So by the time the probe reads the temp, the element has already overheated the wort?

This is very frustrating....

I have auto tuned a few times and it seems to make matters worse, not better.

Here is a picture of my RIMS tube:

View attachment ImageUploadedByHome Brew1451075763.319075.jpg

It's probably about 2 feet long, the element comes right to the bottom of the sight glass.

It's a 1500 watt element. I am using a March pump to recirculate. I usually keep my flow rate pretty low to prevent channeling in the mash tun.

Any thought or further questions?

Thank you in advance for your help.

Your element is too short and therefore maybe also too high a density. It sounds like you are getting local boiling so my bet is it is too short and high density. The delay between the heated liquid and the output is too long and is the real problem, though. The only way to remedy with this setup is to have the flow rate cranked up (which will create a stuck mash maybe) and/or turn the gains way down. Switch to a duty cycle (manual mode, not PID) as a test and you will see consistency at the output.

What you really need to do is get a longer element and have the sensor placed close to the output of the element (say 1-2" max). Think 5500W @240 VAC ULWD and run at 120V = ~1300W.

Alternatively or in combo, you could get a longer sensor probe and put it through the top port. Also, if the sight glass is not critical there, you could remove it.

Your PID is not tuned right. Auto tune doesn't always work correctly, especially when you have variables like flow rates and different outside temps. Even if you get your PID tuned correctly for this batch, it doesn't mean it will work the same next time because different grain beds may not all allow the same flow.
It took a lot of studying what adjustements do what, and trial and error to manually tune mine to work correctly.
Eventually I bailed on RIMS and went HERMS. Not because I couldn't get it to adjust correctly, but because it only takes a few seconds of stuck mash to scorch an entire batch.
I see you have a sight glass on your tube. Is that so you can visually monitor if flow stops?

I am using this element:

https://www.brewhardware.com/product_p/element1500_short.htm

I'm gonna try a different configuration of my rims tube on the next brew day and do as you suggest to shorten the distance between the element and the probe.

I'll see if that make a difference and I'll report back. Thanks!

I am getting some local boiling too.. maybe its because I'm running it at 240v.. thereby increasing the density.

acidrain said:

Your PID is not tuned right. Auto tune doesn't always work correctly, especially when you have variables like flow rates and different outside temps. Even if you get your PID tuned correctly for this batch, it doesn't mean it will work the same next time because different grain beds may not all allow the same flow.
It took a lot of studying what adjustements do what, and trial and error to manually tune mine to work correctly.
Eventually I bailed on RIMS and went HERMS. Not because I couldn't get it to adjust correctly, but because it only takes a few seconds of stuck mash to scorch an entire batch.
I see you have a sight glass on your tube. Is that so you can visually monitor if flow stops?

Click to expand...

Yes, that's correct. I wanted to make sure I could see if something was not working properly within the tube.

I've been messing with the PID values for the last three brew sessions. Doesn't really seem to do anything. Maybe I just don't know what the hell I am doing, but from my understanding, the PID basis its decisions on the history of how temperature is affected by its actions, and then adjusts...

So I have just never had the time to run a blank batch tune it any more.

The system works well as long as I am not trying to do any temperature steps. If I just mash in, it uusaly holds temp to within a degree or so. But If I try to say raise it to 168 for mash out.. its gonna jump up to 180 while it makes its climb.

So protein rests..multiple temp rests..etc..etc..a re basically out the window.. which is the whole purpose of going RIMS.

I'm gonna try to shorten the distance between the element and the probe and see if that helps.

Whoa!! Stop! That's a 120V element!!

You need to switch to 120V, use the long element or better the fold back.

What BrunDog said. Running it at 240v is a recipe for disaster. That'd give you a 6000 watt rims tube.

You can run a 240v element on 120v but not vice versa.

Bobby_M said:

You can run a 240v element on 120v but not vice versa.

Click to expand...

Why can't you run a 120v element at 240v (assuming it still draws less current than the wire's maximum)?

have you got a pulse flow? sometimes when i crush to fine i have this problem and can cause problem to the pid

The wiring and controller might support the higher current, but the element itself is not made to handle it. At four times the design power, it will surely fail. It is an unsafe situation.

The localized temperature is running very hot. You know how we sometimes run a huge 240v element at 120v to decrease the watt density by 4 (30 watts per square inch)? Using a small element and increasing the watt density x4 is bad (280 wpi). The wort flash boils and the element innards are stressing outside of design tolerance.

Nico93 said:

have you got a pulse flow? sometimes when i crush to fine i have this problem and can cause problem to the pid

Click to expand...

No, i have not had that problem... I have a jaybird false bottom and haven't had a stuck sparge yet... knock on wood.

Bobby_M said:

The localized temperature is running very hot. You know how we sometimes run a huge 240v element at 120v to decrease the watt density by 4 (30 watts per square inch)? Using a small element and increasing the watt density x4 is bad (280 wpi). The wort flash boils and the element innards are stressing outside of design tolerance.

Click to expand...

I honestly, can't believe I did something like that. I'm really thank ful you guys caught it. I ordered a 2000 watt 240v element. Should be here on Wednesday. I am wracking my brain for any justification for it, and I can not find it.

Bobby, I tried to find one on your site, but it doesn't look like you have anything less than 5500 at 240.

So this is what I will do. Ill change out the new element and see if that helps.

Dang, now that I am thinking about this... this could become a lot of work...

orangehero said:

Why can't you run a 120v element at 240v (assuming it still draws less current than the wire's maximum)?

Click to expand...

As noted above it will produce 6000 watts on 240. In that length I'm surprised your not flashing the worth to steam. It will draw 4 times the current on 240 also.

If you want range on the setup, you should go to the long 5500w element which can be used on 120 for RIMS temp control or 240 for rapid heat up on high flow.

Flaviking said:

Here is a video of what is happening:

http://youtu.be/-9R9z2k5wuo

I'm not really sure why it is happening, but it seems as if maybe my element is not heating the wort fast enough to register with the probe at the out out if my RIMS tube. So by the time the probe reads the temp, the element has already overheated the wort?

This is very frustrating....

I have auto tuned a few times and it seems to make matters worse, not better.

Here is a picture of my RIMS tube:

View attachment 325247

It's probably about 2 feet long, the element comes right to the bottom of the sight glass.

It's a 1500 watt element. I am using a March pump to recirculate. I usually keep my flow rate pretty low to prevent channeling in the mash tun.

Any thought or further questions?

Thank you in advance for your help.

Click to expand...

I mentioned before in your other thread your element is too short and too high watt density and that this may happen.. You would be much better off spending the $20 on the element I linked in that thread. The 2000w one should work much better than what you have now...

Flaviking said:

I honestly, can't believe I did something like that. I'm really thank ful you guys caught it. I ordered a 2000 watt 240v element. Should be here on Wednesday. I am wracking my brain for any justification for it, and I can not find it.

Bobby, I tried to find one on your site, but it doesn't look like you have anything less than 5500 at 240.

So this is what I will do. Ill change out the new element and see if that helps.

Dang, now that I am thinking about this... this could become a lot of work...

Click to expand...

Or super easy... I could just remove one of the 120 legs going into my RIMS Relay and replace it with a neutral from the power source, right?

That should drop it from 240 to 120 and I wouldn't need to order a new element. Or i could order the longer 5500w 240v element as well, and run it at 120v.

Flaviking said:

Or super easy... I could just remove one of the 120 legs going into my RIMS Relay and replace it with a neutral from the power source, right?

That should drop it from 240 to 120 and I wouldn't need to order a new element. Or i could order the longer 5500w 240v element as well, and run it at 120v.

Click to expand...

that would help but ideally the longer the element the better... you will be less likely to run into scorching issues.

augiedoggy said:

that would help but ideally the longer the element the better... you will be less likely to run into scorching issues.

Click to expand...

thanks Augie.. Really appreciate the help. I'll take your advice and get a longer element as well as drop it to 120v.

Flaviking said:

thanks Augie.. Really appreciate the help. I'll take your advice and get a longer element as well as drop it to 120v.

Click to expand...

nothing sucks more than having to dump 10 gallons of scorched beer... I know this from learning the hard way unfortunately

That's a lot of wattage for RIMS if all you are doing in maintaining mash temp with it. If I were building a RIMS system, I would use the lowest wattage 240 volt heater I could find, and run it on 120 instead of 240. It seems to me that you want the lowest temp rise possible on the wort in the rims consistent with maintaining your mash temp. Of course the PID should effectively control the output of the element if it's set up right. PIDs in my limited experience can be a challenge to configure to operate the way you want. It seems that the more you mess with them the farther you get from where you want to be... at least at first.


I find that with decent insulation my mash temp holds within about 2 degrees. I built what amounted to a BIAB RIMS once, and it would hold my temp to within less than a degree while recirculating my mash. I soon realized that it was just an additional level of complexity with additional systems that had absolutely no effect on the final product. Recirculation didn't improve efficiency, nor did it improve flavor, nor did it make brewing easier or faster. It only meant that I didn't have to take my piece of foam and wrap the mash tun... but I had more to clean up and put away. An interesting project and a challenge, but in the end, a complete waste of time and money... unless you count the learning experience.

H.W.

Besides getting a more appropriate element like most folks have been talking about, you really need to fix what @BrunDog brought up early on: the long lag time between the wort passing over the heating element and reaching the temp probe. The lower the flow rate, the closer the temp probe needs to be to the heating element in order to get non-oscillating temperature control. Having an overpowered heating element makes that lag between heating and detection even worse. The way your system is currently configured, there is no way to get stable control. It's not the fault of PID tuning.

Brew on

Yep, the temp sensor needs to be within a couple of inches downstream of the element to have a high correlation between power input and control. You don't need the sight glass. The temp sensor needs to be right there.

So I dropped the voltage to 120 and shortened my RIMS tube by one full section. and it is now working pretty damn good.

It still goes over my mash setting, but not by more than a degree or two.

Thank you everyone, for your help. I think you saved my from 1) a dangerous situation, and 2) me destroying my whole system out of frustration.

This is what HBT is all about, love it.

Thumbs up and beer clinking icons!