Building a water autofill by injecting water into the pipes?

You need to have a Back Flow Preventer - Further Reading to protect the potable water supply from pool water contamination.

I would put the control valve between the water supply and the BFP input.

I would not use a solenoid with 120V for safety. Use a low voltage solenoid.

Let’s see what @Dirk thinks.

I have something very similar. Orbit B-hyve sprinkler controller controlling an orbit sprinkler valve plumbed off my hose bib. Check valve between sprinkler valve and pool plumbing. Back flow preventer on the hose bib.

ajw22 said:

I would put the control valve between the water supply and the BFP input.

I would not use a solenoid with 120V for safety. Use a low voltage solenoid.

Let’s see what @Dirk thinks.

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I have my motorized valve after my BFP, but that had more to do with ease of installation than thinking it through. One could argue that the motorized valve before everything could save the day. Like if you were away and something down stream of the motorized valve failed and was leaking, or spewing water, the motorized valve could be operated remotely to shut things down. The same cannot be said for the BFP.

Is the auto-fill "toilet valve" still in place? If so, you cannot use a check valve or Orbit valve to feed that. I think the link Allen gave you explains why, or I can if you're curious. This is a good choice for a BFP:


This is the motorized valve you want. It's low voltage, and unlike an Orbit valve, it only draws power as the valve moves. It'll even shut itself off (or on) should the power go out. You choose one that is either normally open, or normally closed. Apply a voltage and it'll move to the opposite valve position, remove power (or if power goes out) the valve will return to the normal position.


That may be similar to what you identified above. If so, that's the ticket. But as Allen warns, do NOT use one that requires 120V. That's just too risky. I tapped mine off of available low voltage in my pool automation system. But I would have used a low voltage power supply had that not been available. The less 120–240V things you have associated with a body of water you put your body of water into, the better!

I have an auto-fill valve, so I got the normally open motorized valve. I only apply power when I want to shut down my auto-fill. I do so at night while my water softener is regenerating, because I don't want hard water going to the pool while that is happening (I fill my pool with soft water). Should the power go out, or something otherwise fails, I want that valve to be open, so my pool doesn't evaporate to the point of starving my pump.

But if you don't have an auto-fill valve, and would be using the motorized valve to fill your pool "manually," then perhaps you'd want a normally closed valve, so that if something goes wrong, your valve will close and not overflow the pool. Think that through...

Dirk said:

Should the power go out, or something otherwise fails, I want that valve to be open, so my pool doesn't evaporate to the point of starving my pump.

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Technically you don’t need to worry about starving the pump if the power goes out.

Bperry said:

Technically you don’t need to worry about starving the pump if the power goes out.

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Actually, there is a "perfect storm" to consider.
- Pool evaporates to lowest point before auto-fill kicks on.
- Power goes out on day one while I'm gone for a week.
- Yes, pump doesn't run, but pool continues to evaporate below skimmer opening (or leaks, or both).
- Motorized valve has defaulted to "normally closed" position so auto-fill doesn't run.
- Power is restored and pump is starved before auto-fill can fill pool, pump burns itself up.

Without the motorized valve, the auto-fill would continue to top off the pool during a power outage. But if my motorized valve defaults to its closed position, it wouldn't. On a hot week, I think it would only take about three or four days for my water level to get below the skimmer. Which is why I wanted a normally-open valve.

What wouldn't work during a power failure is my pool cam, so I wouldn't be able to monitor water level while away. Pretty much the only thing mission critical for my pool is that auto-fill. I could deal with a green pool upon my return, but a burned up pump is a couple grand.

If the OP plans to abandon his auto-fill "toilet" valve, then he might need to consider what will happen to his pool during a power outage event that lasts a few days, or some other failure of his auto-fill scheme.

Dirk said:

Actually, there is a "perfect storm" to consider.
- Pool evaporates to lowest point before auto-fill kicks on.
- Power goes out on day one while I'm gone for a week.
- Yes, pump doesn't run, but pool continues to evaporate below skimmer opening (or leaks, or both).
- Motorized valve has defaulted to "normally closed" position so auto-fill doesn't run.
- Power is restored and pump is starved before auto-fill can fill pool, pump burns itself up.

Without the motorized valve, the auto-fill would continue to top off the pool during a power outage. But if my motorized valve defaults to its closed position, it wouldn't. On a hot week, I think it would only take about three or four days for my water level to get below the skimmer. Which is why I wanted a normally-open valve.

What wouldn't work during a power failure is my pool cam, so I wouldn't be able to monitor water level while away. Pretty much the only thing mission critical for my pool is that auto-fill. I could deal with a green pool upon my return, but a burned up pump is a couple grand.

If the OP plans to abandon his auto-fill "toilet" valve, then he might need to consider what will happen to his pool during a power outage event that lasts a few days, or some other failure of his auto-fill scheme.

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Yea, makes sense. I’m one of those people who don’t trust water automation that costs money when it fails. Automatic sprinklers especially. Seems like I’m always driving by some place early in the morning where there’s a geyser shooting water into the air for who knows how long cause a sprinkler head broke off.

Yep, the more we automate, the more we have to fix!

RichTJ99 said:

just curious the water spigot on the top of your pump

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Spigot is used to drain to waste on cartridge filters.

RichTJ99 said:

Thanks this looks to be very helpful info.



So – how about this combo:



Hose bib

to

¾ NC low voltage solenoid - Amazon.com

to

¾ backflow preventor

Amazon.com

to

¾ PVC check valve (overkill maybe but OK?)

Amazon.com

to

tapped into pool plumbing





Any concerns about brass with salt water? I am converting to salt this season.

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Check valve is not necessary. A BFP is, in essence, doing that same function. And a cheap PVC check valve has no indication that it is working and no way to test if it is. It'll just be an unnecessary weak link in your otherwise very sturdy and reliable parts list.

I suppose some amount of pool water will backwash to the BFP, but the salt level in a pool is closer to that of your tears than the ocean. I don't expect it would do a thing to brass (which is one of the metals of choice on ocean-going vessels).

Unless you anticipate going out to your pool pad for a good cry often, I think your BFP will be OK.

You keep referring to "hose bib." I've been assuming that is your water source. Your pool-filler system should be hard-plumbed to the pipe that feeds that hose bib, not attached to the hose bib itself (like with a chunk of hose or anything else attached to the threads of the bib).

Otherwise, your plan looks good. You might consider a manual shut off valve for your system, so that you can shut it down when you need to. Perhaps you were planning to use the hose bib for that. I wouldn't.

FYI: (I noticed because I had to go back through my first post and make this same correction on what I wrote) The valve you've chosen is "motorized," it's not a solenoid. A solenoid valve, like a typical Orbit used in a sprinkler system, opens, and stays open, as current is applied. It's burning watts to stay open. But a motorized valve opens with a bit of current and then stays open, without using any significant wattage, as long as a voltage is present. It's a small distinction, but a solenoid is a sort of electro-magnet that is using watts and "straining" against a spring to stay open the entire time, where a motorized valve just sit's there, either open or closed, and doesn't consume watts to do either.

Mine is activated (closed) for four hours a night, every night, which is why I chose motorized over solenoid.

Is the pipe feeding that hose bib inside the wall, or external? This is how I connected mine. I connected my filling system to the pipe poking out of the wall, and then attached the hose bib to that. I later insulated it. I included a proper brass shut off valve, too. I use that to manually shut off my filling system when I need to. I used all copper above ground, and only switched to PVC underground. That, IMO, is the right way to do it. Most plumbers will just do all PVC, but technically PVC is not supposed to be exposed above ground (even though your entire pool pad plumbing system obviously is!!).

Notes:

You'll be mating PVC to brass here and there, depending on how you plan to do the plumbing. Personally, I would minimize that as much as possible. As I illustrated above, I used all copper and brass as much as much as I could. Regardless, the important thing to remember when you have to make the transition, is to screw PVC male threads into brass female threads. Never screw metal male threads into PVC.

If you decide to include a manual shut off valve for your system, don't be tempted to use a PVC ball valve. That'll be the first thing that fails. Use a quality brass ball valve. I like 1/4 turn valves for that.

Many plumbers will swear that you use either teflon tape OR pipe dope at your threaded connections, but never both. Just as many will swear that you should use both. I used to be in the former group, but recently started using both. Connections I was making should have been sound, but leaked anyway. Once I started using both, I only had to do it once. My theory is that plumbing parts used to be of higher quality and made with greater precision. But now-a-days, everything is cheap and made in various countries, so the spec's maybe get neglected a bit, and threads just don't fit like they used to. Using both seems to alleviate that issue. Be sure the dope is rated for PVC.

Now if I could only find a 5¢ candy bar...

Sorry, two more things. The BFP needs to be installed a certain distance above the level of your pool water. I forget how much. At least 12", I would think, but it might be 18".

Also, you'll see a couple of test ports, with flat-head screws (like little valves) and the blue shut-off valves. You need to mount the BFP so that there is easy access to all that. The BFP you've chosen is testable (that's a good thing), but the tester needs good access to all those ports and valves. Leave clearance leading into those ports (they attach a hose to those when they test), and face all the valve handles and screws outward (not next to and blocked by the wall).