RIMS: Can not sparge and mash. It's one or the other.

Hello,

So I have built myself an electric RIMS configuration. I'm using a 30amp Kal clone control panel built with the help of hbt user danbass. After going through my first batch, I was hit with some heating problems. It was suggested that I perform an auto tune so that the PID could learn how fast to heat, etc.

At first, I did this for the recirculation into my mash tun. The temperature stays within a few degrees, and works as I would expect it. I end my recirculation, redirect the mash tun to the boil kettle, and proceed to use the RIMS as a sparge water source. I am able to get up to sparge. Well, to boiling, actually - every time.

If I auto tune for sparge as opposed to when I am recirculating, I can keep a great sparge temperature - again within a few degrees, but I would never get there as I find myself having the same problems with recirculating the mash. The temperature will vary from 130-180. Not ideal. It seems as I can only have one or the other, and I'm trying to figure out why. I do know that I can not sparge and recirculate at the same rate of flow, so I'm guessing this may be a contributing factor.

I have played with the "p" and "t" variables without much success. What should I try?

http://imageshack.us/photo/my-images/163/indoor.jpg/

So it is RIMS, not HERMS? Do you have a PID controlling the RIMS element and a separate PID controlling the HLT element?

It is RIMS. See linked picture. I have one PID controlling the RIMS tube, one PID as a glorified thermometer in the mash tun, and one PID controlling an element in the BK.

http://imageshack.us/photo/my-images/163/indoor.jpg/

It has come to my attention that the RIMS = vertical. This apparently does not work so well with sparging. Will be trying RIMS = horizontal this evening, and report my findings.

Auto tune the RIMS for your mash conditions and write down the P, I & D parameters. Then auto tune the RIMS for your sparge conditions. Write down those parameters as well. Next time you brew, manually plug in the mash parameters. When it comes time to sparge, plug in the sparge parameters.

I do basically the same thing using a BCS-460 in a two vessel system, using the RIMS tube as an on demand water heater for 1qt. per minute sparge.

The RIMS tube should work well either horizontally or vertically. I have mine about 5 deg. off of horizontal as that drains the tube entirely when disconnected.

OK, so there were several things wrong with my configuration that I have since discovered.

1. RTD Sensor was at the end of the tube, creating a lag in response times from the element to the sensor. I have flipped the outlet of the RIMS (and in turn the location of the temperature probe) to be in the center. This puts the probe right on top of the element. After doing this, I was still having problems keeping a good sparge temperature.

2. I switched to a different spigot in the basement. The previous one could fill a 5gallon bucket in, I don't know - 10 seconds. Mind you, I only turned it maybe an 1/8th of a turn to get enough flow. I've rerouted my garden hose to a sink that had less flow. I was able to achieve temperatures steadily between 161-169. This leads to the #3.

3. I hadn't considered that I should have a valve on the outlet side of the RIMS, to regulate the flow consistently. I will be testing this with a tri clamp butterfly valve as I am fresh out of tri clamp ball valves, and the local dairy supply wants $150 for ONE.

I expect this final change will allow me to tune at mash temperatures, and sparge at my desired sparging temperature.

See also: https://www.homebrewtalk.com/f51/rims-inline-water-heating-question-402004/

Chuck O is correct your PID is auto tuned to the thermal properties of your mashtun initially, and when you switch to using the RIMS tube for heating your sparge water, the PID does not know you have done it and continutes to use the thermal tuning of your mash tun. You probably get the RIMS tubing cycling on a off quite a but on sparge right?

I don't think the position of your Probe is that much of an issue as long as it is submerged. I had a RIMS tube setup and had the RTD at the opposite end of the tube without issue. I was not doing a sparge through the tube though.

I had success this morning running a water test for mashing and sparging with the same PID values after:

1. Relocating temperature probe to the middle of the tube.
2. Changing my fresh water source to a lower flow spigot.
3. Placing a valve on the outlet of the RIMS tube.
4. Tinkering with the valve on the outlet of the RIMS tube and the water-in shutoff valves on my manifold.

For reference (although your system will be different), my PID values for P,I,D were:

I=265
P=14
d=25

Hope this helps someone else.