RIMS Question: Air in the lines during recirc

Hello all,

This is probably a very stupid question, so I apologize in advance.

I have an old school sabco system at home and am rebuilding it to be a bit more advanced. Part of it blew up on me (I'll explain in a second...), so I figured while I'm repairing it I might as well change some of the equipment out.

I've brewed many a batch on the system. I set the temperature on the PID controller, start the recirculation process, adjust the temp controller so it syncs with the thermometer, and periodically bleed off air. Somehow air was getting in the lines during the recirculation process.

I made the mistake of walking away during a recirculation a week ago. About 10 minutes later I hear this noise from the garage, and run out to see boiling wort spraying all over the garage ceiling through what used to be the air bleed valve. Apparently air had built up in the RIMS tube....

So my question is this... How do you guys prevent air from getting in your lines during your recirculation? I saw the sabco guys at the NHC this year and they say that their new system does something automatically to prevent this so no bleeding of air is ever necessary.

My first guess is that you're taking on air somewhere in your plumbing. I have a march pump and RIMS and once I'm primed, I'm primed.
Or could you be actually be boiling in your RIMS?

I'm taking apart all of the plumbing and reworking it, so hopefully that will fix it.

You could do an air or Co2 leak test once you get finished with just 3-4 psi. Soapy water or starsan the check for leaky joints.

Another possibility - you're recirculating too fast and air is entering the mash through the sight tube on the mash tun (assuming your tun has a site tube).

Good tips, thanks guys.

Noleaf, Have any pictures of your system? Specifically the RIMS/pump plumbing?

I don't think you are having air build up in the system. If you were that would mean you have some kind of leak on the suction side of your pump. With the pump stopped it would start leaking. Also, with enough force to blow out of the bleeder valve like that, you wouldn't be sucking in air, well, if you were using something like a march pump or little giant that is.

The fact that it was blowing out the valve leads me to think of two things. You lost prime on the pump, or there is some kind of restriction on the output side of the RIMS unit. The way your bleeder valve was operating make me believe that it is a pressure relief valve, which is a good thing to have.

So even if flow stops moving through the RIMS tube the controller should stop it before it gets that hot, I'm thinking the process control temperature probe is located in the wrong spot as well. Again, pics would be worth a 1000 words.