RIMS Rocket Temperature Control

[Mike Kropp]

I was doing a test mash yesterday with water to verify my setup of the Blichmann RIMS Rocket. I routed hoses as follows:

mash tun -> RipTide Pump -> RIMS Rocket (bottom input) -> sparge arm

At the top of the RIMS Rocket I had a Tee fitting with the tee mounted as shown in the RIMS Rocket manual: The flow outlet was out the side of the T and the temp probe (PT100) vertically in the top. The probe was connected to a PID controller with an SSR controlling the RIMS Rocket heater.

I've used this probe/PID setup for other purposes and it has always worked well.

With this configuration, the probe was registering temperature fluctuations all over the place. The PID kept firing the heater as expected but was not able to lock in a stable temperature at all -- it just kept bouncing all over the place with values steadily rising towards my set point.

When not mounted in the tee, the probe reads a very steady temperature as expected.

I tried different flow rates but had no success. It was almost if the probe wasn't maintaining good contact with the water even though the tip was present in the opening of the tee.

Any suggestions?

 

[Schreiner]

The flow and your set up is the same as mine, other than you're using the RIMS Rocket, rather than a generic rims tube. You need to tune your PID to modulate the element correctly.

From my experience, you should circulate as fast as you can without compacting you grain bed, and causing a stuck mash.

 

[Mike Kropp]

Autotune didn't work because of the wild constant temperature variations. I'm wondering if there was an air pocket or something.

 

[augiedoggy]

Autotune didn't work because of the wild constant temperature variations. I'm wondering if there was an air pocket or something.

I would try swapping the probe mounting with the outlet or at least turn the tee so the rtd come in from the opposite side as the exit since you could very well have an air pocket there.

I'm guessing here but depending on the flow speed the fluctuations could possibly just be from unevenly heated liquid. this is why rims are usually a narrow tube instead of a small kettle, the exposure to the heating element is more uniform which helps with more consistent temps exiting.

 

[LuckyBeagleBrewing]

I set mine up where the temperature probe tip is in the flow path of the output and my pid tunes perfectly. The tip is right after the center of the tee.

 

[augiedoggy]

I set mine up where the temperature probe tip is in the flow path of the output and my pid tunes perfectly. The tip is right after the center of the tee.

View attachment 593050

thats what I meant by my comment above.. no air trapped this way.

 

[logdrum]

I’ve got my probe in the bull head of the T, so the wort flow always immerses the probe. Also using a (120v) RIMS Rocket with great results..

 

[Mike Kropp]

Well I brewed yesterday and had to monitor the RIMS Rocket manually. My PID, a JLD612, couldn't control it because the temperature would never settle down. I redid the tee as LuckyBeagleBrewing did above in a horizontal orientation. That didn't help. I'm thinking the temperature probe is the issue. When there is no flow, it reads just fine but as soon as I switch on the pump, it starts jumping all over the place (even with the RIMS Rocket completely off). Once I shut the pump off, it settles down again in a bit.

This is the probe I'm using: http://amazon.com/gp/product/B071DW3GVQ

What are others using? My PID can handle any of the following:

The probe I'm using is a PT100 (P100) from the table above.

Any and all suggestions are welcome as I am planning on brewing again in 2-3 weeks.

 

[augiedoggy]

Could be some sort of ground loop, is the rtd jacket the stainless braided cable? If so and if its attached to the connectors at both ends I bet you have a ground loop. I had the exact same issue and behavior on my rims on both my homebrewing and the 3bbl system I built before I realized what was happening.

 

[Ozarks Mountain Brewery]

The probe I'm using is a PT100 (P100) from the table above.

I don't care for the stainless braided coating, they kink and short out a wire

 

[augiedoggy]

I don't care for the staleness braided coating, they kink and short out a wire

me either but even after I switched to the teflon wires they had a shielding wire I made the mistake of grounding at each end until someone pointed out that it can cause the issue in the automation section. they should be grounded at one end.

 

[Mike Kropp]

Could be some sort of ground loop, is the rtd jacket the stainless braided cable? If so and if its attached to the connectors at both ends I bet you have a ground loop. I had the exact same issue and behavior on my rims on both my homebrewing and the 3bbl system I built before I realized what was happening.

Interesting. What did you do to solve it? Also, What would cause the ground loop?

 

[Ozarks Mountain Brewery]

I use these cables, they work fine, only problem then is my soldering skills which are lacking

https://www.auberins.com/index.php?main_page=product_info&cPath=20_15&products_id=333

 

[augiedoggy]

Interesting. What did you do to solve it? Also, What would cause the ground loop?

The ground carried over on the element power cable as well as the additional ground transferred through the rtd cable.

I removed the shieding connection between the rtd plug and rtd wire..