Manifold Suction Problems

WillH · Feb 21, 2019

I am looking for some help for someone to help me figure out why I cannot get my manifold to work in the way I think it should work. Hopefully someone has had this problem before and solved it, but I am very confused on the science behind the issue and how to solve it. I am sure it will make sense if someone can explain it to me and propose a possible fix!

Water comes in from utility pump into the bottom of the uv light, then up and over to the manifold. The water then travels down to the right and back into the tank. I have lifted both the return and extra return I have here out of the water to ensure that was not the issue.

Everything appears to work just dandy on the main line, but when I open a manifold valve, the main line gives me a gurgling noise (appears to keep working like normal) and the reactor on the manifold just gets bubble, like there is a large amount of suction on it. I do not think water is even come out the valve at all, from what I have tested, but it just bubbles, like it is sucking in a bunch of air.

jda · Feb 21, 2019

Is the air purged out of all of the lines? If so, then I don't have anything else, so free bump...

Breadman03 · Feb 21, 2019

So the main line is open ended? If so, you may be creating a Venturi with the branch lines. I'd try adding resistance to the end of the loop (a thumb could work well if it won't spray everywhere) and see if you get the flow you expect.

ca1ore · Feb 21, 2019

Where does the ‘down to the right and then back into the tank’ actually go - I cannot tell from the pictures. If the manifold valves are higher than the mouth of the return then they’re more likely to suck air than expell water. You’d have to put a ball valve on the ‘down to the right’ line to create some back pressure and divert water through the manifold valves.

WillH · Feb 21, 2019

Breadman03 said:
So the main line is open ended? If so, you may be creating a Venturi with the branch lines. I'd try adding resistance to the end of the loop (a thumb could work well if it won't spray everywhere) and see if you get the flow you expect.

Yes, I had both under water on the sump side at one time, but I starterd moving them back out of the water to see if that helped, so they both sit above the water now

WillH · Feb 21, 2019

ca1ore said:
Where does the ‘down to the right and then back into the tank’ actually go - I cannot tell from the pictures. If the manifold valves are higher than the mouth of the return then they’re more likely to suck air than expell water. You’d have to put a ball valve on the ‘down to the right’ line to create some back pressure and divert water through the manifold valves.

Yes, its about 7 feet higher, I was curious about this. I will try the ball valve, that sounds like my issue. I was guessing the falling water was the issue.