Mysterious Siphon from ATO?

[texhorns98]

So my relay failed on my ATO from autotopoff.com. They are taking care of it for me promptly, which I of course appreciate!

I disconnected the switches, etc. and left the tube in the sump, still connected to the aqualifter pump. This was yesterday morning. I noticed some waste water discharge from the RODI yesterday afternoon which means SOMETHING had to have pulled water out of the reservoir. I go to check the sump and it's risen a good couple of inches!! HUH? I pull the tube out, and no water is coming out of it (save a few drops from being submerged).

Call a few people who can't figure it either, and decide to put the tube back in the sump again and mark the waterline. Sure enough, over night another couple of inches!

Normally, I could write this off as simple siphoning...BUT, my reservoir is across the house and the water level in there is probably 18 inches above the water level in the sump. The water has to go up the tube probably close to 2 feet, go down into the crawlspace, travel 20 feet, and then (the kicker) go BACK UP almost three feet and over into the sump!

I even blew air back through the hose until there were bubbles in the reservoir. Is it possible that the actual flow through the sump is causing water to pull from the reservoir? Normally, the tube is not submerged...this time it was. Sorry for the long post, it took some splainin' to get my issue across!

 

[texhorns98]

bratliff;346881 wrote: IMO, if the flow through your sump is causing that much of a siphon, you have too much flow! To test, I'd put the line back in your sump the way you found it and go down to your ATO and see if you see any water creeping back up the tube. Is it possible your pump came on?

I only have about 700 gph running through the system, I don't think that's excessive, do you? I would do like you're saying, but the tube is not see through. No way the pump came on because it was unplugged from the ATO relay. Hmmmm...

 

[texhorns98]

ares;346903 wrote: "my reservoir is across the house and the water level in there is probably 18 inches above the water level in the sump"

this seems to pretty much sum it up.... if the resevior is above the sump, it WILL drain out. with all that distance, it may be absurdely slow, but given 10 hours or so, itll get it done anyway.

I thought about that as well, BUT then I would ALWAYS have that siphon occurring, right?

 

[texhorns98]

Yeah Brett, the pump has to pull it up two feet out of the rubbermaid 20G container.

 

[texhorns98]

ares;346913 wrote: yep... need to make some sort of syphon break in it somewhere.

Yes but I DON'T always have this siphon going. I would have surely noticed by now after almost a month. The only time I get the siphon is when the tube itself is submerged in the sump water column. That's why this thing has me baffled!:doh:

 

[texhorns98]

Standard RO/DI sized tubing. 1/4" I'm pretty sure...

What you say makes sense...kinda... :lol:

 

[texhorns98]

It won't do it if I pull the tube out. While the ATO is in the shop, I'll just pop the tube down in there over night and BOOM, instant top off! If I weren't so lazy, Id tell them they can keep the ATO and just give me my money back!

NOW you see why I titled this thread "Mysterious..."

 

[weaglereefer]

I don't think it's that mysterious. When the tube is submerged and the sump level falls, it tries to take the water in the tube with it. When the tube is submerged at normal level, the pressure is equal, but when the water falls, the pressure drops outside the tube starting the siphon which may be just enough pressure to overcome the Aqualifter's internal mechanism. When the tube is above the water, there is no difference in pressure in the tube, and because of surface tension, when the water level drops, there is no siphon. It only needs to be a small force to get a little siphon started, and a drop of a few mm in water level may be enough.

 

[texhorns98]

Ahhh...but chew on this, the level in my sump only drops in the return section. The tube is placed in the fuge section which remains constant! I'm telling you, it's "mysterious"!

 

[wbrown]

what's the chance of a brief power outage overnite? Just long enough to refill the sump and break the siphon from the tank. Power comes back on, water level drops, and starts a siphon from your top off..

 

[texhorns98]

wbrown;347003 wrote: what's the chance of a brief power outage overnite? Just long enough to refill the sump and break the siphon from the tank. Power comes back on, water level drops, and starts a siphon from your top off..

I can see how that would work in theory, but I would know if the power went out because I would have a few clocks blinking. Guess again...:tongue:

 

[texhorns98]

Yeah, but what would cause it to start siphoning once removed and the placed back in the sump? Sump flow? I'm temped to take the tube running into the pump and place IT in the sump...see if it still siphons. All in all it's such a slow flow it doesn't TRULY matter. It would take 3 or 4 days to overflow the sump, if even that quickly.