L2 flow rate help

[jepuskar]

Hi, I have a new Vectra L2 I am trying to dial in the actual flow rate of to setup a UV sterilzer. My Hydros was reporting about 600gph at full power and I've been scratching my head.

So I took the flow sensor out of the equation and just filled a 5G bucket up in 13 seconds, using 2 feet of 1 1/4" tubing straight from the outlet of the L2 turned up to full speed. If my calculations are correct this is about ~1384GPH

Checking the L2 graph this rate should be around 10ft of head pressure, which there is no way with 2 ft of 1 1/4" tubing.

I always assume I am doing something wrong and it's not the equipment, so what is wrong with the above? I am filling up a 5G HD Homer bucket and the timer starts when water comes out of the end and stops right at the top. Driver is constant green and turned all the way to the right.

thanks,

 

[Sisterlimonpot]

It's been debated many times that the claimed flow based on head pressure has been exaggerated.

Your numbers seem to be in the ballpark.

I don't know what hydros uses to sense flow rate, but it sounds like that method can be thrown out as a means of accuracy. I'd be curious if their software requires other data points to get closer to accuracy... but I'm just guessing

So 2 things are true from your tests, the flow sensor is incorrect and the exaggerated numbers from marketing don't cross over to real world applications.

I've verified your math and you're correct with your guesstimate for water volume. Even if you were off by a split second, you're in the ballpark.

How do you translate what you learned into achieving the proper flow theough your UV? Well it gets even more complicated because you'll probably end up using a manifold to split the flow rate, and that becomes even more intense to calculating flow through each branch of your manifold, minor changes can dramatically alter flow in all the branches.

A while ago I used cad software to simitate flow theough plumbing and was amazed at just changing a 90° elbow to a 45° made, and how nothing is equal.

The best approach is the same thing you did to test flow through the pump, is to plumb everything and then dial the flow through the uv based on time and filling up a known volume.