Using ATO as sump overflow security?

Pigpen17

New member
Hey RC,
So could you have your return pump in your sump set up on an ATO switch and only use the OFF sensor in your tank as security against tank overflow?

I was thinking of using it with only the OFF sensor, or setting the ON sensor well above the waterline or just out of the tank so it's always on and the OFF as high as it can be under the tank lip.
 

alexgv14

New member
You can do that. Seems kind of odd though. Also, remember float switches fail pretty often and you would probably want some sort of backup method. I probably would not recommend doing that. The best option would be installing another emergency drain for situations like that.
 
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Pigpen17

New member
Yeah, I have never heard of anything like this before, so there must be a reason why not.

My concern is I am going to use a HOB overflow, for many reasons. From what I understand, if the overflow loses suction, there is no safety net to stop your pump from overfilling your tank. If you have ATO in your sump, this could add the volume of your RO water on your floor as well. I was thinking a switch on your return could save you a lot of heartache.

Please keep in mind this is my first sump attempt and I have no idea what I am talking about.
 

ryeguyy84

New member
I have a sump low switch that shuts off the pump if the sump level is too low. in theory this should work like you are trying to do except mine just failed and I burned out my pump when my ATO was empty. My other safety is a ATO timeout so if the switch did work and the ATO was filling and allowing the pump to run it wouldn’t overflow the display.

Hope that makes sense, this is all done through an apex.
 

morleyz

New member
Yeah, I have never heard of anything like this before, so there must be a reason why not.

My concern is I am going to use a HOB overflow, for many reasons. From what I understand, if the overflow loses suction, there is no safety net to stop your pump from overfilling your tank. If you have ATO in your sump, this could add the volume of your RO water on your floor as well. I was thinking a switch on your return could save you a lot of heartache.

Please keep in mind this is my first sump attempt and I have no idea what I am talking about.

Your safety net is making the return section on your sump small enough that if your return pump completely empties the return section, your tank does not overflow. If you're going to use a HOB overflow, this is the only way to insure you do not overflow your tank. Float switches can help, but they're very prone to failure. With a small return section, ATO is probably a necessity.

If you lose suction, it is possible that you'll burn out your return pump in this situation, but it won't overflow your tank. You also need to make sure your sump has enough excess capacity to accept whatever water drains back to the sump when you shut off the return pump.

I would recommend that float switches only be used for notification purposes along with something like an Apex, so you know something is wrong, but don't act on those unless you have redundancy and are constantly checking the switches to verify functionality.
 

Sk8r

Staff member
RC Mod
FLoat switches and check valves are not a guarantee against flood.
You need enough space in your sump to contain all the water that comes down at pump shutdown, that's all. A doublewalled overflow box prevents the tank draining down.
 

Shaummy

Member
I could also see this potentially cycling your return if water flows back to your sump when the pump kicks off...which fills your return section enough to fire up your pump and start it all over again.

I guess if you had a quick enough siphon break on the return line it may not happen...but not sure.
 

Pigpen17

New member
Thank you all.

I have a sump low switch that shuts off the pump if the sump level is too low. in theory this should work like you are trying to do except mine just failed and I burned out my pump when my ATO was empty. My other safety is a ATO timeout so if the switch did work and the ATO was filling and allowing the pump to run it wouldn’t overflow the display.

Hope that makes sense, this is all done through an apex.



Yes. In fact it is way simpler than what I was thinking. Thanks.

And I was thinking about the fact that the return section of the sump would be the safety net by running dry with just a small amount of water running in to the tank. Wouldn't my ATO kick on though? and start to refill the sump and therefor keep the pump running until my ATO is empty as well?

I could also see this potentially cycling your return if water flows back to your sump when the pump kicks off...which fills your return section enough to fire up your pump and start it all over again.

I guess if you had a quick enough siphon break on the return line it may not happen...but not sure.

Oh yeah. It might. Hmmm.
 

ryeguyy84

New member
Thank you all.





Yes. In fact it is way simpler than what I was thinking. Thanks.

And I was thinking about the fact that the return section of the sump would be the safety net by running dry with just a small amount of water running in to the tank. Wouldn't my ATO kick on though? and start to refill the sump and therefor keep the pump running until my ATO is empty as well?



Oh yeah. It might. Hmmm.

I use an Aqua lifter pump for my ATO because it is very low flow. I also have my ATO timeout after I think 5 minutes. when it times out I get a text and e-mail to say "hey there's something going on here" and I can take action from there. The ATO won't turn back on until I reset it.
 

Pigpen17

New member
I use an Aqua lifter pump for my ATO because it is very low flow. I also have my ATO timeout after I think 5 minutes. when it times out I get a text and e-mail to say "hey there's something going on here" and I can take action from there. The ATO won't turn back on until I reset it.

Now that's handy. I am guessing that is with a controller? Not on the shopping list yet, but the longer I am at this the more I am finding out that everything will be eventually.

I'm still thinking about this. There's a new ATO out that is a one or two float switch. The "Simple" ATO. I could hook up the single switch inside the tank above the waterline so it is "ON" all the time. Then if everything else fails and the tank fills to the rim, it would shut off. Right? Then I could put the real ATO in the sump and have no worries about it refilling the sump during a suction break?
 
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