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I conducted an experiment. The results are up for discussion

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limulus

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1. Is it better to insert a temp probe into a RIMS tube or in the mash?
2. Is it better to control wort return flow with a valve or pump speed?

I had always preferred to have my temp probe either directly in my mash or inserted into a compression fitting at the outlet of my MT. Numerous people have told me that was not the ideal way. I won't say that I was told it was wrong, but just not best. I've also read and been told that the best way to control flow is by using a valve instead of a speed control on my pump.

Tonight I installed a new thermowell from Brewers Hardware into my RIMS tube. I used the valve between my RIMS tube and MT to slow the flow of water (not a real mash) in my test. This valve placement assured me that my element stayed wet. My PID was reading 151F after warming from 45F. So, I inserted a long dial thermometer directly into the wort and it was showing around 100F. Then I inserted my Cole-Parmer thermoprobe directly into the wort and it showed the same. So, I removed my PID probe from the RIMS tube and inserted the Cole-Parmer probe into the RIMS tube. It immediately shot up to 152F just like the PID display. I then tried to insert the PID probe directly into the wort but it was too short to reach (so I can't prove my results without a doubt). I next opened my flow control valve all the way and the PID temp display started to fall immediately. So after a 15-min period to equalize, I checked the temp again. The PID was showing 126F with the probe inserted into the RIMS tube and the Cole-Parmer probe was showing 125F inserted directly into the mash.

Based on my quickie experiment: the part about inserting the PID probe into a RIMS tube seems to be good advice but IMO using a ball valve to control the flow backs up wort in the RIMS tube and causes the PID temp display to be inaccurate compared to the rest of the mash. So maybe I should move my valve to a position before the RIMS tube. Maybe what I have discovered is both pieces of advice are correct but my valve should be before the RIMS tube. But then am I risking the loss of a heating element? That probably depends on the layout of the RIMS tube. If it is vertical (mine is horizontal) with the element on bottom and the input on the bottom with the output on top, the element stays submerged. I have another set of conditions to apply to my experiment.
 

LakewoodBrew

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It would help if you had a schematic layout of your test configurations. It's entirely possible to have different process temps at different locations in the system. A schematic can help explain why.

BTW - a ball valve - although convenient and cheap is not a good way to throttle a flow. I'm a sucker for cheap sometimes but a gate valve is much more effective for flow rate control. Ball valves are superb for fast acting on-off. Also, Pump velocity as a means for flow rate control is not so great with turbo dynamic pumps like mag drive stuff because they are not designed to be run at anything but the rated speed and the flow rate / back pressure curves may not be what you expect (quickly stalling as you drop down towards your desired flow rate giving sketchy and un-stable performance)
 

Catt22

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It would help if you had a schematic layout of your test configurations. It's entirely possible to have different process temps at different locations in the system. A schematic can help explain why.

BTW - a ball valve - although convenient and cheap is not a good way to throttle a flow. I'm a sucker for cheap sometimes but a gate valve is much more effective for flow rate control. Ball valves are superb for fast acting on-off. Also, Pump velocity as a means for flow rate control is not so great with turbo dynamic pumps like mag drive stuff because they are not designed to be run at anything but the rated speed and the flow rate / back pressure curves may not be what you expect (quickly stalling as you drop down towards your desired flow rate giving sketchy and un-stable performance)
+1 Good advice. I use gate valves for both flow control on my pump and also for regulating the flow from the HLT when fly sparging. They were a major improvement in flow control precision. You can achieve a similar result if you add a six foot long extension to the ball valve handles.:D I've attempted to share the benefits of using gate valves this way for quite some time, but I have gained only a very few converts that I am aware of. People get attached to their valves I suppose and especially so if they bought the 3-piece stainless ball valves. I've also tried to relay the benefits of using large diameter hoses and fittings, but only rarely have I heard of anyone actually replacing all of their expensive silicone hoses and QD's with the larger stuff. I do understand that sometimes it's very difficult to bite the bullet. Been there myself more than once.
 
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