My RIMS job

[The Pol]

This is what I was talking about... if you measure temp at the MLT outlet, the PID cannot possibly realize that the heater output to the MLT is say, 160, 170....? It has no idea what that element is doing in there. You could have a 1500W element pumping out 160F wort, or a 4500W element pumping out 190F wort and all the PID will SEE is the MLT outlet temp is either at its set point or not. If you control the heater by its own ouput temperature, then you will never run the risk of sending hot wort that has overshot your MLT target temp into your MLT, because the PID will SEE it.

When building my HERMS I read a lot about where to measure temps and the outcome of measuring it in different areas.... basically stated was the fact that if you measure it anywhere other than at the heater outlet you run the risk of overshooting your temp. Your controller has no idea how hot your heating chamber is.

 

[Lil' Sparky]

Is there a way to have 2 temp inputs for a PID?

e.g., one in the mash controlling the overall activity - is the mash high/low/good - and another one at the RIMS/HERMS output for fine-grain control over the heating element so that you never overheat the wort.

 

[davebl]

This is what I was talking about... if you measure temp at the MLT outlet, the PID cannot possibly realize that the heater output to the MLT is say, 160, 170....? It has no idea what that element is doing in there. You could have a 1500W element pumping out 160F wort, or a 4500W element pumping out 190F wort and all the PID will SEE is the MLT outlet temp is either at its set point or not. If you control the heater by its own ouput temperature, then you will never run the risk of sending hot wort that has overshot your MLT target temp into your MLT, because the PID will SEE it.

When building my HERMS I read a lot about where to measure temps and the outcome of measuring it in different areas.... basically stated was the fact that if you measure it anywhere other than at the heater outlet you run the risk of overshooting your temp. Your controller has no idea how hot your heating chamber is.

Interesting POL. I was looking at the Brew-Magic, which is what I am cloning, and they have the temp probe on the output of the MLT.

I guess some in-depth testing will be in order before a first batch.

 

[The Pol]

You really do not want the heater to send wort to your MLT that is hotter than your MLT set point. If you want your MLT at 152F, there has to be a way to make sure that the wort coming into the MLT is 152F. Otherwise your mash temp will overshoot. Keep us posted on how the PID handles that.

 

[davebl]

You really do not want the heater to send wort to your MLT that is hotter than your MLT set point. If you want your MLT at 152F, there has to be a way to make sure that the wort coming into the MLT is 152F. Otherwise your mash temp will overshoot. Keep us posted on how the PID handles that.

Another thing I thought of is that the PID turns the heater on or off. So if there is an issue with the wort getting too hot, I can just up the flow rate on the pump.

BTW, Pol, on your HERMS what size tube do you use? I am thinking of either 3/8 or 1/2 hard stainless tubing for my system.

 

[The Pol]

Everything on my rig is 1/2"... on previous versions of "The Beast" I used 3/8" and the flow rates are SO much faster with 1/2" that I would never go back. From the ball valves to the HERMS coil to the tubing, it is all 1/2". I highly recommend it.

3/8" components may be slightly cheaper, but the difference in flow and ability to prime my pump is incredible. I know a lot of people convert coolers with 3/8" hardware, if they only knew how large the difference was with 1/2" plumbing!!!

 

[Lil' Sparky]

+1 on the 1/2" tubing!!

 

[missing link]

I initially built something almost identical and I tried to put the temp probe on the outlet. My first brew seemed to be going OK until the probe called for more heat. I wasn't watching extremely close, I was just confident that my system would work, well by the time the hot wort on top got to the probe and shut off, my whole mash had been over heated. I watched in a panic as my temp climbed to 168 even though the element was off.

After this I switched to the outlet of the heat exchanger and I put a digital thermometer at the outlet of the MLT. Once the system stabilizes they are within 1/2 degree of each other for the entire mash.

One other major question on your design. How are you getting the air out of the heat exchanger? If you have both outlets pointed down, it will take you forever to purge enough air out to ensure your element is completely submerged. You need at least one fitting to point up, or at least out the side. My outlet points up and I have to recirculate water for a good 5 minutes before I stop getting bubbles out of the heat exchanger. I recirc for a bit before turning the element on.

Linc

 

[The Pol]

I think with HERMS and RIMS the placement of the temp probe is really important. +1 on the orientation of the inlets and outlets when pumping, air is tenacious with the March pumps.

Remember if you place your temp probe on the HEX outlet, you cannot run a system where the pump only runs periodically, otherwise when the pump is off, the temp probe (wort) will cool in that area, commanding the element on when you do not want it on. I am sure you are going to use a constant recirc, but some dont, and this can be a real issue.

 

[davebl]

I think with HERMS and RIMS the placement of the temp probe is really important. +1 on the orientation of the inlets and outlets when pumping, air is tenacious with the March pumps.

Remember if you place your temp probe on the HEX outlet, you cannot run a system where the pump only runs periodically, otherwise when the pump is off, the temp probe (wort) will cool in that area, commanding the element on when you do not want it on. I am sure you are going to use a constant recirc, but some dont, and this can be a real issue.

I do plan to recirculate 100% of the time. I think I'll put the probe on the output of the HEX based on POL and Linc's advice. I don't know about directly at the output though, would you think heat transfer from the stainless itself could affect the probe? I think putting in a tee a foot or so down the line might be ok?

 

[The Pol]

Well, the SS should not be any hotter than your wort, really... but a foot should not be too far from the HEX.

I think that will work MUCH better than taking the temp at the HLT outlet, because you want your PID to monitor your heater, not the temp 5' away and 10 minutes in the past.

The other dude that posted about his 168F mash temp is what I am afraid of. The further you get from the HEX, in TIME and distance, the more inaccurate your HEX control will be.

I think we are getting this figured out.

 

[Beerwolf]

I've done a lot of experimenting with thermocouple placement and have mine in a thermowell in the RIMS heater outlet. I've got a RIMS heating setup very like yours, but double-barelled with a second stainless tube connected in series. I run a low density heating element in each tube. No caramelising, and I use a fast flow rate to minimise lag in heating. I run the heater at 1 degree above desired mash temperature with a PID.

 

[missing link]

I built a heat exchanger very similar to yours. Mine is 1 inch copper about 12 inches long. The wort comes in one end and exits via a T near the base of the element. I then have a 6 inch nipple with another T. My thermowell goes into this second T. One thing to keep in mind here is that a thermowell for a 1/4" temp probe in a half inch pipe will not flow enough wort. I had to upgrade to a 3/4" nipple and T.

With this set-up, my Love Control set at 152 gives me 152 +/- 0.5 degrees on the outlet of my mash tun. I have a digital thermometer on the outlet of my mash tun that reads to 0.1 degrees. It is amazing how accurate it is.

The best part is that using beersmith to calculate my strike temps, I lower the strike water by about 2 degrees from what beersmith gives me. I let the system stabilize for a while. Normally I fill everything with the proper quantity of water, turn it on, set my temp and walk away for an hour. I don't use any gas except to boil. When I dough in, the temp fluctuates and slowly drops to just below the set point. It then takes about 5 minutes to get right back to the set point and maintain. I have never had to worry about nailing my temps this way.

Linc

 

[davebl]

Just got back from my local stainless fitting shop with 20 feet of 1/2" stainless tubing. The tubing comes in 20 foot sections, and this one had a kink about 18" from one end. They didn't have any more stainless in stock to choose from. So they ended up giving me the entire 20 feet. Talk about a deal.

Now I have to finish paint (its just about completely primed) and start bending up and routing plumbing.

 

[davebl]

So, we ran into a little problem. Somehow, we made some measurement mishaps (personally I blame me with homebrew and a tape measure). My mashtun was too high to drain into the boil kettle properly.

So I debated on new plumbing, which was tossed because I have all of my stainless, fittings, etc.

So then I thought about lowering the boil kettle. I couldn't do this because of my gas plumbing and the fact that the welds were difficult to cut and then dropping the BK posed other problems.

So we raised the upper tier. I had to cut and then weld in extensions. It honestly came out pretty good. After some grinding, I don't think it will be noticeable. Everything came out true and good and square.

 

[davebl]

And we finished up at the perfect, correct height.

 

[bakins]

Somehow, we made some measurement mishaps (personally I blame me with homebrew and a tape measure).

Yeah, I've made a few of those mistakes as well

Never work on electrical stuff after a homebrew or 4. Trust me.. Thank God for GFCI...

 

[scinerd3000]

nice welding...i dig the shot with the other end in the air! Cool

 

[davebl]

Got the boil kettle burner plumbed in today. I can only get it up to around 25 PSI's due to a safety valve in my propane tank. Still plenty of heat output.

 

[bakins]

How long is the element you are using? looks shorter than the ULD ones I use in my HLT and BK.

So would a 3/4 inch outlet with thermowell then stepped down to 1/2 be better from what you guys are saying?

 

[Seabee John]

Got the boil kettle burner plumbed in today. I can only get it up to around 25 PSI's due to a safety valve in my propane tank. Still plenty of heat output.

I noticed you were using the same burners as my brother in law has on his rig. I was wondering what the spacing is between the top of your burner and the bottom of your keg?
The reason for asking is if your burner is too close to the keg, your gas will not burn as cleanly and you run the risk of high out put of CO gasses. I'd hate to see you get hurt. Remember, if you see orange flame off of a gas burner, you are producing CO, and just because you don't see orange flame, it doesn't mean that you are not producing CO. It doesn't take much to harm you. Nick is running between 3.5 and 5 inches of space on his, yours looks to be about 2 inches.... just wondering.

 

[The Pol]

+1, yeah you will definately not want them too close.

 

[Emian]

Finished up the RIMS Heater.

What you see:
a Lowe's 4500 watt 240v heater, but it will be ran at 110v to yield about 1000 watts
8" 1.5d Stainless nipple
2 x 1.5" Stainless tees
2 x 1.5" to 1/2" Stainless bushings
1.5" to 1" Stainless bushing (to mount the heating element)
1.5" Stainless plug
....

That looks like what I was intending to do - only where you have your plug, I was going to put a 1/8 bushing, to mount the thermocouple.

Where are you intending to mount your thermocouple?

Ian

 

[davebl]

I noticed you were using the same burners as my brother in law has on his rig. I was wondering what the spacing is between the top of your burner and the bottom of your keg?
The reason for asking is if your burner is too close to the keg, your gas will not burn as cleanly and you run the risk of high out put of CO gasses. I'd hate to see you get hurt. Remember, if you see orange flame off of a gas burner, you are producing CO, and just because you don't see orange flame, it doesn't mean that you are not producing CO. It doesn't take much to harm you. Nick is running between 3.5 and 5 inches of space on his, yours looks to be about 2 inches.... just wondering.

I have about 2.75 inches between the keg and the burner. It's a little shorter than what I was wanting (3.5"). I should have the plumbing 100% done and can then do some test boils soon.

 

[davebl]

Finally some updates.

1st, moving has slowed the process down. I finally got to a place and have a lot of things unpacked. I'm now having trouble getting some spare stainless parts so ordering everything online has also slowed the works.

Pol was great in convincing me to move the RTD to the exit of the HEX. I fitted a stainless tee with plumbing hard-lined into one side, the RTD on one, and then the HEX on the other. I didn't rotate the opposite end of the HEX 180 degrees from the other, only 90ish... I think that should help purge air.

Bending the stainless was tricky. I ended up destroying about 6 feet of my 20 just learning how to bend. A conduit bender ended up being the trick, although the radius is much larger than what i was wanting. It worked, but I wanted tighter bends.... again, oh well.

 

[davebl]

This is my first attempt at bending.

Hard plumbed drain to boil kettle and the HLT drain which fees back to the HEX.

MLT and HLT plumbed in.

 

[davebl]

And the plumbing is pretty much done. I need two fittings for the final HEX to MLT section to be finished.

Overall, I'm pretty happy. The wort path is 100% stainless, except for one 12" section of vinyl I'm putting in for a sight glass (until I find a true sight glass solution).

 

[scinerd3000]

And the plumbing is pretty much done. I need two fittings for the final HEX to MLT section to be finished.

Overall, I'm pretty happy. The wort path is 100% stainless, except for one 12" section of vinyl I'm putting in for a sight glass (until I find a true sight glass solution).

if i remeber correctly search Bobby_M and he has sight glasses made of pyrex glass that he sells. As for your tubing, what diameter tube are you using, they look fairly small

 

[Bobby_M]

Negative on the pyrex. So many people were breaking the glass that I just couldn't stand behind the idea. My rig does have Pyrex tubes but they're 100% shielded from my clumsy ass.

 

[davebl]

if i remeber correctly search Bobby_M and he has sight glasses made of pyrex glass that he sells. As for your tubing, what diameter tube are you using, they look fairly small

I was thinking about pyrex or polycarbonate tubing. I am using all 1/2" diameter thinwall stainless.