Siphon question for auto top off system

[Olathereefer]

I am getting ready at add a Tunze 3155 auto top off system to my setup. The pump and top off water will be stored in a 32g Brute container. The plan is for the supply line to run from the pump out the top of the container, down the outside of the container, through the wall or (under the baseboard), and into my sump. In order to prevent a siphon, does the supply line into the sump need to be higher than the Tunze pump inside the Brute storage container or does the supply line into the sump need to be higher than the top of the Brute storage container since the supply line goes over the top of the container?

 

[mcgyvr]

When the output is lower than the input a siphon can/will form..

See here..
https://en.wikipedia.org/wiki/Siphon

 

[Olathereefer]

The pump inside the storage container will be below the return line that is going to the sump which will not allow a siphon to form. What I am not sure about is the fact the the supply line will be going out the top of the storage container which will be higher than the sump and I am not sure if that factors into the siphon issue or if I just need to have the supply line higher than the pump itself?

 

[SethO]

If the water level in the ATO container is lower than in the sump a siphon will be created.

What you need to do is create a break in the line at any point higher than the ATO container. An example is to run a CPVC pipe into the sump and simply drop the ATO pump output into the CPVC pipe.

 

[Jimbo327]

Check Valve

 

[SethO]

Check Valve

Not always reliable.

 

[JamesHolt]

Three rules for ATO system..
1. All check valves will eventually fail, you don't need them, don't use them..
2. The output FROM the storage container needs to be higher than the highest level in the storage container..
3. The output from the ATO pump should NEVER go into the sump water regardless of the water level in the sump..

 

[jewlz]

You can add an air-break to the system if you need to pump from a container that is higher than the eventual output... no check valves required....

 

[hann1bal]

I have same issue. I want to have the ATO drain to SUMP because there is less issues with it falling out of tank like if I run it up to DT. Does anyone have a suggestion to this problem.

Will a check valve work?

 

[hammond0]

I've seen too many check valves fail over time, I would never recommend them.

 

[sleepydoc]

As state above:

1. Don't use a check valve.
2. The should always be an air gap between the outlet of the ATO tubing and the water level of the sump/tank.
3. The outlet of the ATO tubing needs to be ABOVE the water level of the ATO reservoir.

If the ATO reservoir is at or below the destination tank it's generally no problem. If The reservoir is above the destination tank, you can do one of three things. The easiest (IMO) is to have the ATO tubing empty into a trough or piece of pipe that's above the water level of the reservoir, then let the water run down to the tank from there.

The second option is to put a tee in the tubing somewhere near the top. Depending on your ATO pump and the pressure it generates, you may need to extend a piece of tubing up from the tee so the water doesn't spurt out the top when the pump runs.

A final option is to use a peristaltic or similar pump that doesn't allow water to siphon, essentially using the pump as the check valve. The other two are generally cheaper and easer to do, though.