HELP: overflow sucks in air...

[zalnn]

Hi All,
I'm in the process of building DIY PVC overflows for a 55gal. I'm using the design pictured bellow.

Problem: at the inlet (top ob pipe B) a vortex is created and air gets sucked in, breaking the siphon! How do you guys overcome this? What am I doing wrong?
I even tried using a 90* at the end of B (inlet).

My overflow is exactly as pictured. The levels of E-D-E are the same (within 1/16 of an inch).
Section C is an inch above the tank.

 

[davcheng]

i've been told that 2 90* at the end of "B" would make it so that it doesn't suck in air

 

[rocker92]

is your water level too low?

 

[stumble]

Maybe you can turn it down so you are not moving so much water and sucking as hard

 

[rocker92]

did you get it working?

 

[Burko]

"What am I doing wrong?"


Did you prime it correctly?

 

[zalnn]

i've been told that 2 90* at the end of "B" would make it so that it doesn't suck in air

That is not a bad idea; the 2 x 90* will need a small hole to let the air out so that the water can actually flow when it reaches the inlet

is your water level too low?

don't quite know what you are asking? once the siphon is working, when i simulate a power outage (stop the pump) the water level goes down to the level of the inlet (top of B). Then when I restart the pump, the water level rises, but as it drips into the inlet air gets sucked in as well.

Maybe you can turn it down so you are not moving so much water and sucking as hard

The would defeat the purpose of having this type of siphon, or I am going to need a lot more siphons.

did you get it working?

Not yet.

"What am I doing wrong?"
Did you prime it correctly?

Yes. Got ALL the air out of the siphon.

 

[yogurt_21]

what size pipe did you use?

 

[cypher1024]

You haven't capped the top of pipe 'C' have you?

 

[zalnn]

what size pipe did you use?

3/4" schedule 40 PVC

You haven't capped the top of pipe 'C' have you?

I tried without a cap, with a cap and with a cap and variable hole. No luck... still getting the vortex that causes air to be sucked into the siphon.

Arrrgh!!!