Hidden Closed Loop Intake

[banditpowdercoat]

Closed loop wont drain the tank. Its Closed. from overflow, straight to pump inlet, then out of pump, back to tank, right?

[Dez]

Originally Posted by banditpowdercoat

Closed loop wont drain the tank. Its Closed. from overflow, straight to pump inlet, then out of pump, back to tank, right?

Yes, however it's not so closed anymore once there is a drain in the overflow. Take a look at this diagram that I quickly mocked up (white box is the pump) If you have a power outage, the whole tank is going to drain to the level of the standpipe (standpipe drains to sump - I didn't continue it in the diagram). The water is going to go through the return at the bottom of the tank, into the overflow, and drain down the standpipe in the overflow box. Meaning in the case of this diagram, almost half of the tank would be drained to the sump. Please correct me if I am wrong, but I think that I've thought it through alright in my head. Mr. Alberta said that this exact thing happened to him so he doesn't run the inlet of the closed loop in the overflow box anymore.

[golf nut]

If what you have drawn is correct, then as the power goes out the overflow would fall to the level of the standpipe going to the sump, the water in the tank would force water back through the pump and into the overflow which would go to the sump.

you are correct, the tank will drain to stand pipe level.

[Delphinus]

Ohhhhh oh ho !!! Tricky, very tricky!! It took me a while to see it, but yes now I see it. The outlet has to be higher than the standpipe if you don't want that to happen.

[Delphinus]

Or I guess a check valve.. But I myself don't like having to rely on a check valve to prevent a flood.

[Delphinus]

You've lost me. What was the original question? I thought you were asking if you could have your CL intake in the overflow box. Or are you asking about the additional hole in the overflow box?

[Delphinus]

Oh ... wait. The question is about whether it's a good idea to use an overflow box that doesn't lead to the sump at all?

Interesting. That seems like it could work. No idea what pitfalls to expect but it seems like a workable idea..

[Dez]

Now that we have it sorted out that I can't have the intake in my overflow (due to using Herbie Style Drain and don't want water draining out and wanting returns on the bottom). Any suggestions on the original purpose of this thread? How does my original hand drawn diagram look? The idea is to have that as a completely separate box.

(I spent way more time than I should have on that mock up diagram of "what if power failure occurs when inlet is in overflow box)

[golf nut]

Originally Posted by Delphinus

Ohhhhh oh ho !!! Tricky, very tricky!! It took me a while to see it, but yes now I see it. The outlet has to be higher than the standpipe if you don't want that to happen.

Then what happens is the tank settles to the level of the closed loop feed, then the water in the overflow drains to the standpipe height.

When power comes on there is no water in the overflow for the closed loop pump and it runs dry....play it safe .... do it right.

[mark]

My tank is two sides viewable as well, with the overflows on both ends.

My CL intake is midway up the side of one of my OF chambers, plumbed straight through to my CL pump (does not draw from the OF chmber). As you're trying to avoid, is covered with LR but seems to work.