Best Orientation for RIMS ?

[Sawdustguy]

You are a braver man than I. Maybe you are right it is and autotune problem. Let me ponder this a bit. If it is particular to using autotune I still would encourage RIMS brewers to install a flow switch because I would bet the majority of brewers use conventional PID's and autotune.

 

[Sawdustguy]

FYI.....I used to use just the alarm relay as a safety but here is the thread that casued me to install the flow switch: https://www.homebrewtalk.com/f51/burned-out-heating-element-rims-140750/

 

[Sawdustguy]

FYI.....Here is the thread that casued me to install the flow switch: https://www.homebrewtalk.com/f51/burned-out-heating-element-rims-140750/. There is a great picture of a RIMS that almost caused a fire in the middle of the thread.

 

[Ohio-Ed]

FYI.....Here is the thread that casued me to install the flow switch: https://www.homebrewtalk.com/f51/burned-out-heating-element-rims-140750/. There is a great picture of a RIMS that almost caused a fire in the middle of the thread.

I was not that brave... it was a pretty controlled test. I first ran it with the PID set at 100f so I had plenty of time to shut off the element if it got out of control.

I don't think it has anything to do with autotune. I was actually pretty impressed with the BCS out of the box.

I think the PID is "working/applying energy" to adjust the temp of the full volume and when it suddenly (in the case of a stuck mash, or my case a closed valve), it puts that same energy into heating just the volume of the RIMs chamber.

A couple things I realized during the test;

As in the case you linked to... If the RIM's runs dry (because of a leak, or it hasn't been filled yet), the element will likely burn up before the temp probe reaches the setpoint.

Also, A stuck mash means your pump input is going to be shut off... so you risk burning up a pump.

In the end... I think the flow switch is a GREAT idea. It should prevent you from burning up an element in the event of a dry fire AND it will save your pump and possible your element in the case of a stuck mash.

As I was looking at the flow switches... I noticed the ones I saw had a filtration rating between 100 and 150 microns. Is this an issue for us circulating our mashes? Also, when you see a rating like .25gpm, is that the minimum flow to engage the switch (I'm assuming that is not a max flow rate through the switch)?

Edit: A couple more thoughts...
I think if your setpoint was closer to boiling temp, you would be more likely to have the problem CodeRage described. In that case, the overshoot that I witnessed would put you above boiling and the water would quickly evaporate. At the setpoint, I was at, there was enough time for the PID to adjust before it got near boiling.
Also, I think the amount of overshoot I witnessed (about 10f), is related to the volume of my rims heater. My heater is copied from SawDustGuy's "RIMS for Dummies" thread and is 2" in diameter. A smaller volume, would likely have a much greater overshoot (possibly to the boiling point).
And finally... this test was done with a BCS-460, not a PID, they may operate differently in this situation.

 

[willynilly]

I have been running my BCS about 6 hours a day lately...

Here is what I have seen.

Running at full flow I had a 20F rise from the INLET to the OUTLET of the RIMS tube. At 9000W there was no indication of flash boiling (noise or bubbles)

The generic PID settings in the BCS performed very well.

I shunted the flow from full to half, still, the PID did not overshoot. The outlet temperature did not exceed the setpoint to any real degree.

I dont think that one has to worry about burning up a pump with a stuck mash. I have had numerous stuck mashes and never a pump issue. These pumps do not need FLOW, they need to be WET. A week after brewing, they are still wet enough to be lubed.

I have some concerns about how my RIMS will work in the case of a stuck mash. My RIMS temp. probe extends into the RIMS tube slightly, it is NOT down-line. My pump is UPstream of the tube, RIMS outlets are up.

 

[Ohio-Ed]

I have been running my BCS about 6 hours a day lately...

Here is what I have seen.

Running at full flow I had a 20F rise from the INLET to the OUTLET of the RIMS tube. At 9000W there was no indication of flash boiling (noise or bubbles)

The generic PID settings in the BCS performed very well.

I shunted the flow from full to half, still, the PID did not overshoot. The outlet temperature did not exceed the setpoint to any real degree.

I dont think that one has to worry about burning up a pump with a stuck mash. I have had numerous stuck mashes and never a pump issue. These pumps do not need FLOW, they need to be WET. A week after brewing, they are still wet enough to be lubed.

I have some concerns about how my RIMS will work in the case of a stuck mash. My RIMS temp. probe extends into the RIMS tube slightly, it is NOT down-line. My pump is UPstream of the tube, RIMS outlets are up.

So, does this mean the pump "could" pull the liquid out of your RIMs chamber resulting in a dry fire?

I have mine configured with the pump in front of the RIMs heater. My thought was that if the mash sticks... the pump cannot push air, so the output side would remain filled and thus the RIMs heater should not empty. I also have my RIM's configured with the inlet pointed down and the outlet up.

My RIMs is only 1500 watts... with 9000 watts, you may have an atomic event in the case of a stuck mash and zero flow

 

[Sawdustguy]

I was not that brave... it was a pretty controlled test. I first ran it with the PID set at 100f so I had plenty of time to shut off the element if it got out of control.

I don't think it has anything to do with autotune. I was actually pretty impressed with the BCS out of the box.

I think the PID is "working/applying energy" to adjust the temp of the full volume and when it suddenly (in the case of a stuck mash, or my case a closed valve), it puts that same energy into heating just the volume of the RIMs chamber.

A couple things I realized during the test;

As in the case you linked to... If the RIM's runs dry (because of a leak, or it hasn't been filled yet), the element will likely burn up before the temp probe reaches the setpoint.

Also, A stuck mash means your pump input is going to be shut off... so you risk burning up a pump.

In the end... I think the flow switch is a GREAT idea. It should prevent you from burning up an element in the event of a dry fire AND it will save your pump and possible your element in the case of a stuck mash.

As I was looking at the flow switches... I noticed the ones I saw had a filtration rating between 100 and 150 microns. Is this an issue for us circulating our mashes? Also, when you see a rating like .25gpm, is that the minimum flow to engage the switch (I'm assuming that is not a max flow rate through the switch)?

Edit: A couple more thoughts...
I think if your setpoint was closer to boiling temp, you would be more likely to have the problem CodeRage described. In that case, the overshoot that I witnessed would put you above boiling and the water would quickly evaporate. At the setpoint, I was at, there was enough time for the PID to adjust before it got near boiling.
Also, I think the amount of overshoot I witnessed (about 10f), is related to the volume of my rims heater. My heater is copied from SawDustGuy's "RIMS for Dummies" thread and is 2" in diameter. A smaller volume, would likely have a much greater overshoot (possibly to the boiling point).
And finally... this test was done with a BCS-460, not a PID, they may operate differently in this situation.

If you look again JVD_X had the meltdown with a very low flow not a dry RIMS tube. Also, if what you assume is correct, the sensor should have sensed the high temperature in the tube and had the PID shut the element down. There has to be more here than meets the eye. It makes for a good thought about this. Now I am totally befuttled.

 

[Windsors]

Guy,

To followup on Ohio Eds questions, I saw where you you the .25gpm switch. Did you find that the 1 gpm switch was not sensitive enough in our low flow rate application ? Why did you switch it out from 1 gpm to .25 gpm ? The 1 gpm FS's are easier to find (including yours) than the .25 ones.

Thanks

Bill

 

[willynilly]

So, does this mean the pump "could" pull the liquid out of your RIMs chamber resulting in a dry fire?

I have mine configured with the pump in front of the RIMs heater. My thought was that if the mash sticks... the pump cannot push air, so the output side would remain filled and thus the RIMs heater should not empty. I also have my RIM's configured with the inlet pointed down and the outlet up.

My RIMs is only 1500 watts... with 9000 watts, you may have an atomic event in the case of a stuck mash and zero flow

No, because my pump is UPstream of the RIMS... that means BEFORE the RIMS, not after. After would be DOWNstream

The RIMS does not run at 9000W while mashing, that is only for getting my strike water to temp. 10 gallons in 20 minutes from tap to 170F.

 

[Sawdustguy]

Guy,

To followup on Ohio Eds questions, I saw where you you the .25gpm switch. Did you find that the 1 gpm switch was not sensitive enough in our low flow rate application ? Why did you switch it out from 1 gpm to .25 gpm ? The 1 gpm FS's are easier to find (including yours) than the .25 ones.

Thanks

Bill

I saw both on ebay and bought them both. I figured I would start with the most sensitive. I can't ever see me limiting the flow in the RIMS loop to 1 gpm so that will work also.

Guy

 

[Tom_FL]

Old post here but if folks are still paying attention I am curious if you can just set a higher temp point in BCS that triggers a full shutdown (I.e. rims tube temp probe reaches 180 and system alarms and shuts down).