Overheating / Dry fire in RIMS

Is there any good way of protecting against overheating in a RIMS setup…
Lets say you get a stuck mash or forget a valve (personal experience) your element will heat up very quickly, and any liquid motion to your sensor will be lost so no temp reading…

  • flow sensor?
    -liquid sensor?
    -pressure sensor?
    -auto shut down over 100deg?

is there any good way of doing this??

I also have thought about his. I was wondering if there is a way to add that the pump comes on anytime the rims tube is on. I could also add a Liquid sensor at the top of the rims tube… but the pump needs to be on. I matter what!

You could use a Logic Actuator. Set the RIMS PWM (setting > 0) as input, and the pump actuator as output.
Add a delayedOff constraint to the pump actuator so it keeps pumping for a few seconds after the actuator shuts off.

I think software protection is the wrong approach. It is not safe enough.

You should let a float switch interrupt the signal to the ssr if there is no water.

You can also add a temp sensor to the rims and use a cascaded PID similar to the herms setup, so the mash temp will set the target for the rims output temp.
But you need hardware dry fire protection anyway.

Hardware is probably safest but software protection could be useful. On the output temp probe of the RIMS, If you could set a “High” setpoint on the temperature input to the PID which would prevent the PID from giving an output while above that setpoint. Also if connection to the temp element is lost it should also give 0 from the PID, but not sure maybe it’s like that allready…

Only done one batch on the RIMS setup with the spark so far. I used combined temp sensor, RIMS output and in the middle of the MT. At one point the mash got stuck and the temp out of the RIMS was rising very quickly. After adjusting the flow a little better everything was ok.

The problem with software protection is that if there is no water, the temp sensor would not read a high value. You should detect the no water case in hardware and block he heater from turning on, regardless of software.

You could look at using a setpoint driver, similar to the herms wizard output.

On this setpoint driver, you can set a maximum temp difference.

If the PID has no valid input, it turns the output off. With a combisensor, invalid sensors are ignored and the value is taken from the valid sensors. I designed it with redundancy in mind, so try to keep maintaining temp based on the info still available.

Yea, a flowswitch in the rims loop connected in series withe the ssr could be a solution. If there are any suitable flowswitches around :see_no_evil::grinning:

Or maybe a clamp on temp switch on the outside of the rims tube…

How is the rims tube mounted? If it is vertical, a float switch would work.

I’m not at home right now so I don’t have a picture of it, but it’s similar to the one in the picture. The rimstube is directly mounted with a tri clamp on the MT.

Perhaps you can somehow mount a float switch like these in a triclamp tee, in a direction that flow will also push it upwards.


Yea maybe that could work

I whole Heartedly agree that mechanical is better. even when there is liquid in there my biggest problem is remembering to turn the pump on when I have one to many!

Thank you for the reply, I ended up rebuilding the system to a HERMS setup after it nearly went up in flames. ( I left the room for a few minutes and forgot to close a valve) So after that I don’t dear to run a RIMS without some sort of protection…
I think the best solution would we a flow sensor, as you will destroy your beer if the RIMS tube starts to boil. But as you mention the safety of running this thru SW is not good enough…

Maybe a flow sensor with is own micro controller that makes it require a minimum flow to run the heater can be a solution??

Physical/electrical flow switches exist. You can rig one as dry fire protection on the circuit without it requiring software.

im struggling with this a bit. could u explain differently. sorry

As discussed earlier: for safety failsafes, the less complexity, the better.
Just like float switches, there are flow switches that only close a circuit when they (mechanically) detect flow.

You can place one on your heater circuit for dry-fire protection that doesn’t need software.

I have ordered the parts to make this happen. Buttt I still need to make sure the pump is running. Because it will Scortch the wort. Not the end of the world. But would be nice to have it as I’m very use to being reminded by a warning.

A warning is still useful, but the fail-safe already prevents your wort from being scorched. If the fail-safe is configured correctly, then the “failed” state is that your heater never turns on.

but my rims tube can easily be filled and have no flow. so the element will just sit there and cook when it over fires expecting to be a constant flow

I think you misread my earlier post. I suggested to get a mechanical flow switch.