Drain valve for water table

Inspired by this thread, I’ve added a water storage tank for my water table, plumbed for compressed air to refill the tank and a simple manual operation to drain the tank. With this new setup I now drain the tank after every use and refill when I want to do a run. Refill time takes 63 seconds (for CrossFire water table, not your honking big ocean you have with the Pro!) and drain is mostly done after 2 minutes, but the last little bit takes a while. Not that I care on drain, it’s just open the valve and walk away…
I’ve coupled a float switch with the refill so now I just flip a switch, it fills, and stops filling when the float switch triggers. Easy peasy and let’s me do other prep while it’s filling.
Here are the key photos, let me know if you want deets…
Tank View:

Float Switch:

Pressure Regulator and Flood Switch:

The pressure regulator is a modified “Medium Pressure” Propane regulator (5PSIG) so I have fine control on the tank pressure and neither blow up the tank or wait forever for it to refill. The LED on the Flood control tells me when the solenoid is activated.


Pretty slick, is the solenoid 120volt or 12. Also like the magnetic tape measure on the side of the rail.

Solenoid is 12VDC, mainly to keep the wiring safe and within low power switching capabilities of the float switch. I’ll include PN in BOM. Tape measure is my rough gauge that I find useful in all my CNC equipment. Sometimes you just need to know sort of where you are… I’ll add that to the BOM as well.

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Looks like you have some plumbing and electrical experience

Even though there is an isolating gadket there, I think it is using the water as the conductive material from the valve to the water to the slats, to the piece… At that point the gasket makes no difference. But I do pretty much the same as you. Clamp directly to a side rail, or slat…

what kind of hose is that for drainage? been searching for something flexable like that.

I think it’s called “Heater Hose”, but it’s 3/4" and I got it at Lowes in the Plumbing department. Definitely worthwhile selection! I think the 1/2" barbs fit into it, but it could be 3/4". In any case, the barb fittings are in the same area as the hose so try the fit while you’re at the store.


@TomWS is it a 0 to 20 psi regulator? I haven’t been able to find a 0 to 5 PSI one. How much do the sides of your tank bulg when filling? Thanks!

Both good questions, first answering the second questions, yes, even at just s few PSI, the tank bulges so I put a pair of ‘U’ frames over it to contain the swelling. The tank probably would have been ok, but it certainly didn’t look OK.
Re the pressure regulator: https://www.amazon.com/gp/product/B07BHF6ZD6
You will need to remove the fitting on the input side of the regulator and replace it with an adapter to 1/4" FTP thread. I forget exactly which adapter, but it might have been this one: https://www.amazon.com/gp/product/B07DKK2J5G

To lift the water (without creating a shower) the few inches to the water table, you only need about 2.5 PSI. Anything else is potentially problematic IMO.

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Thanks. I put mine in a storage bin in case it blows a fitting. I don’t want to ever have to clean up 10 gallons off the floor if the tank blows. :). I am using an air pressure regulator but as you know its not great at regulating low pressure.

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Has anyone successfully installed a sub-flush drain so that all of the water drains? Do you have pictures and/or links to the drain fittings you used?

Here’s what I did:

You’ll have to scroll down a bit in the thread to see how I fitted it up. Best way to do it? Probably not, but it’s been working great for me.

Brazing that pipe in there and then sanding it flush is genius! …but way beyond my skill level… haha

Van stone flanges work great.

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I went ahead and ordered two of those from Amazon. https://www.amazon.com/Spears-Fitting-Flange-Schedule-Spigot/dp/B00ALMLVBE

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Yep that will do it. You will need to cut a spacer with the table, or stack some gaskets. I stacked two gaskets to get the seal.

Did you use 1/2" bolts to attach it?

I believe so. I ordered flange bolts since the initial bolt/washer setup leaked… obvious now lol.

Looks like the flange he order is 1/2 inch. Mine are 1 inch.

No, i ordered 1" flanges, maybe have copied the wrong link, same product though. And yeah, i had to do the same thing as you, i had to stack gaskets to prevent leaking and also prevent the water table from bowing. I’m not a craftsman, but here is my result:

I forgot to take a picture of the middle gasket.

Update: The two-layer gasket combo wasn’t enough and it started bowing the table, going to try three layer (two large center holes, one small center hole).

Update2: Here is the triple-layer gasket. I’m still waiting for the PVC cement to fully cure, so i won’t be able to test for leaks until the morning.

Update3: I can tell it will leak before even finishing putting it together, the inside pipe in the flange isn’t squeezing tight enough against the table… I’m completely at a loss, now…

Update4: I kept the three-layer gasket, but added huge washers on the top side to allow more torque on the bolts and prevent the rubber washers from squeezing out. I was able to get 10ft-lbs on the bolts, so we’ll see if they leak when I fill 'er up tomorrow. :slight_smile:

Update5: No leaks!