Solenoid Valves

[E_rock]

On my quest for a new auto top off system. I was wondering if anyone has used a Solenoid Valve to plumb directly into the RO system.
So far from what I see the real advantage is not needing an RO tank for top off and no need to fill said tank.
But on the down side theres alot of risk hooking your tank up to an endless supply of water. I have read a number of ways to combat this. Multiple float switches, mechanical float valves, timers.

It kind of sounds like this is old technology. Not really sure, just looking for input.

 

[SkiFletch]

Relaible solenoids are also not cheap, and are energy hogs for what little they do... I'm never a fan of a system allowing endless RO water into the tank as a possibility, even if there are 2 or 3 levels of protection. Not to mention the other mode of failure, not enough water if one of the multiple parts fails when you design a system with too many fail-safes.

Back when I used an ATO (don't anymore) I had a dual-float switch setup, with a 3rd emergency cutoff all feeding from a resevoir with no more than 5g. My total system volume (sump, etc) is around 70g, so I figured even if all 3 float switches failed, I'd only drop my sg by 5/70, 33PPT, which while not ideal, isn't going to kill anything quickly. I would manually fill the resevoir when it would get low, which in the winter was twice per week, and in the summer around every other day. Now I just use a constant-duty metering piston pump and adjust the speed and stroke weekly to keep a nice equillibrium in the sump. It's max GPD is 4, so even if it does stick on, it will be a long while before any troubles rear their heads.

 

[E_rock]

What's the max head pressure on a pump like that

 

[jpjr]

I have a setup with my ro directly plumbed to sump on a float valve and also have a water timer that I got from lowes that only allows water into the ro unit twice a day for 30 min. That way if the float sticks open, the water supply to the ro will shut off after 30 minutes anyway. When I need to make saltwater, i shut off the supply to the sump, turn on the valve to my mixing barrel and turn the timer on to manual mode. Been almost a year and So far so good with this setup! I can get you the number of the timer when I get home if you want...

 

[E_rock]

Yeah that would be good I would like to take a look at it.

 

[SkiFletch]

Most metering piston pumps are capable of 100-250PSI, so a LOT of head. No prob if you want to run it in your basement They're decidedly NOT cheap, but robust as anything, and the adjustability is wonderful. More commonly used for industrial applications and for swimming pool acid or chlorine dosing. The programmable ones are KEY for outdoor pools in dealing with the variable chemical demands of such a system. For us, they're phenomenal for any chemical dosing, especially kalwasser which is what I have it do. No tubing to replace like with peristaltics, and continuous duty if necessary. LMI makes the best ones in my experience, and they're more marketed to industry, but youc an find them on Ebay. Just be careful, you don't wan to buy a used one that dosed chlorine to someone's pool...

 

[jpjr]

Sorry it took a while to get back to you... Had flat tire on way home, what an ordeal!!! Anyways, here is the item number from Lowes: 159978. I believe Walmart sells it also if you Google Orbit 1 Dial Electronic Hose Timer. It shows not avail at lowes.com but I have seen them in my local Lowes. Hope this helps!!

 

[E_rock]

skifletch i pmed you a link to you one. Let me know what you think.

 

[E_rock]

jpjr flat tires are never fun.
Thats an interesting device looks like it could have alot of other uses in hobby not sure if I would use it as an ATO into the tank though. I will have to keep that in mind though possibly automated water changes or to fill my ato bin.