Please help me set up my RIMS PID

[timweber]

I set up my prototype brewery last night and ran into some problem with the PID settings. This is what I am trying to do.

Temp0 is in the RIMS
Temp1 is in the Mashtun

State0: heat to 165 when Temp1 >= 165 move to state1
State1: PID Temp0 at 165 user input to move to state2
State2: PID Temp0 at 154 for 60 minutes
State3: raise temperature to 168

I have a 10 gal Blichmann Mashtun with 3 gallons of water in it, no insulation, no lid. I am using thick walled opaque silicon tubing. My RIMS heater is a 1500 ULD element. I am cycling the water with a march pump at a very slow flow rate. The protype was in my living room, ambient was 68F.

When in state 2 I can't get the mashtun temperature correct. I raised the setpoint temperature to 160F but I am afraid to go much higher. At that set point the temperature in the MT fell to 147. Following this guideline (http://www.omega.com/temperature/Z/pdf/z115-117.pdf) I divided the proportional gain by 2 making it 10. This made the problem even worse and my MT temp fell to 140 before I stopped trying.

Am I PID controlling the wrong temperature? Are my setting wrong? Thanks for any insight or help you can give me.

Here is a picture of my prototype.

photo.jpg (171.02 KiB) Viewed 5012 times

[ECC]

One thing to check is if your PID is associated with the correct Temp input. You list the PID with Temp0, which is the RIMs. What was the RIMs temperature doing in State2?

If you post your configuration file, I could load it up on a BCS and take a look at your process for obvious errors.

[timweber]

Hmm, I am thinking that my heater element isn't strong enough to compensate for the heat loss in the system. I used an additional element to bring it up to 160. When only the RIMS was on the temperature fell steadily. I am using a 1500 watt ULD heater guess I have to switch to a LD heater. Bummer, $20 down the drain.

[jmdenmark]

Hi Tim,

I assume you are using the Rubbermaid cooler as a hot liquor tank.

Before you upgrade the element, try insulating the mash-tun. It doesn't do much for the cosmetics but the thin stainless without a lid means you are giving up a ton of energy to the living room.

I use a HERMS instead of a RIMS and keggles instead of Blichmann vessels so not exactly apples to apples but I'm sure the lack of insulation is the biggest issue. In my config with the keggle wrapped in Reflectix and an insulated lid the element is not cycling on very often to maintain 154° temperatures.

Jim.

[timweber]

Thanks Jim,

Actually, I never got a chance to try the HLT. It might as well not be in the picture.

Last night I had 4 gallons of water in the MT, runing to a pump, runing to the bottom, of the RIMS, past the element and then back into the top of the MT. I used two element to heat the water one was in the RIMS the other was a normal 1500 watt element. when I removed the normal element the steadily fell even though the RIMS element was turned on.

I had heard of others using this type of element, but they must have used it with a cooler MT. There is just too much heat loss the way I am doing it.

[jmdenmark]

I'm not sure from your answer. Are you planning to insulate the MT eventually or leave it uninsulated? It seems that increasing the watt density could result in other issues with flow-rates and scorching. Given the surface area and material of the Blichmann mash tun I think you may still have the same issue if your aren't going to insulate.

The Reflectix is a nice option because 1. its cheap 2. it works and 3. its removable. I only wrap my MT during the mash and remove it after so my brewery still looks like a brewery.

[timweber]

WELL, I feel stupid. Two things, I put the lid on my mash tun, and, uhhh, I provided power to my heater element. I had the control panel plugged into a GFI and it had tripped.

Sorry to waste your time. The system works PERFECT now. It held 154 to within 0.2F. I am very impressed!