Pump issues

[caedus]

Hey guys,

So I have been doing a pretty damn good job at keeping O2 out, but one thing I noticed today was when I run my pump with both the input and the output 100% open there seems to be a spiral of gas coming out of solution through the sight glass (mounted directly after the pump inline).

All the threads are tight and there was no where else to suck in air. The pump head was secured tightly and there wasn't any play in the parts.

Is this something anyone else has observed? I feel like I am going crazy. If I am not being clear I can post a video on youtube about it tomorrow to provide some visuals.

[lupulus]

[caedus]

That is pretty much what I started doing, I decreased output flow and the it returned to normal.

Would using a bigger pump fix that issue?

[Techbrau]

I can't imagine why you'd need to pump hard enough to introduce cavitation.

[caedus]

This is a little tiny solar pump mounted directly to a pump manifold.

[lupulus]

How much flow are you getting in L/min when the flow is laminar?
What's the size of the input? Is that input the recommended input?
You may also have cavitation because of restrictions before the pump. Getting rid of elbows and twists/turns before the pump can help.

[Owenbräu]

Input side should always be bigger than the output. The inline stainless heads make cringe, but if you restrict the outflow enough you essentially accomplish the equivalent of a smaller output.

[Weizenberg]

Whatever the setup, even with self-priming pumps, make sure your pipes/hoses are fully bled and that your speed is as gentle as possible.

[Smellyglove]

You're saying that you're doing a good job keepng o2 out, does this mean boiling your mash water? If you use a false bottom, is the water degassed before it is transferred to the mash tun? False bottoms can accumulate air underneath them during degassing, which will find its way into your flow.
Air will also come out of solution whenever your raise the temps in the mash. if the water has not been degassed.

It can also be cause of turbulence, as others above me has stated. You'd want to have a pretty straight line into the pump, just before it.