top off question

[russell_wiley]

I was thinking of running my RO directly to my tank triggered by a solenoid valve. The valve would be turned on/off using my float switches.

Has anyone done this? Do you have pics? Any suggestions?

Thanks,

Russ

[Mountaineer]

I would advise against this. What happens if the solenoid valve or float switch gets stuck in the open position? Your tank will become hyposaline and could be disastrous. I would prefer a fixed amount of water in a top off container so the damage would be limited should this occur.

 

My .02

[Origami]

A recipe for disaster. If a float valve fails, your salinty will crash as you continuously add fresh water. Don't do it. Use a top-off container that has a limited volume.

 

My system is set up so that I have a 10 gallon top off container which is refilled automatically once a day within a small time window from my larger RO/DI storage container (a 44 gallon Brute). The most that could possibly get dosed in my system is 10 gallons and that is unlikely since my topoff pump is a timed peristaltic pump. The RO/DI system is tied to the Brute using a float valve for control of production.

[russell_wiley]

Could I run the RO to the container with a float valve& timer? Then, have that pump into my tank via the float switches?

[Mountaineer]

Could I run the RO to the container with a float valve& timer? Then, have that pump into my tank via the float switches?

 

I would say only if you turn the RO off when it is full and not leave it on. If you leave it on and the switch is stuck the container will never empty and just keep pumping more RO into your tank until it is all RO and everything is dead. Why risk it?

[russell_wiley]

That is the reason for connecting the timer to the solenoid. I would have the RO pump into the container at set times, which should increase the redundancy.

[Origami]

That is the reason for connecting the timer to the solenoid. I would have the RO pump into the container at set times, which should increase the redundancy.

 

You didn't mention the timer before.... Also, when you say "pump into the container," are you pumping into your tank or into a container attached to your tank? Are you controlling the solenoid with the combination of a timer and float switches? What happens if the solenoid fails in the open state? It seems that you still have a design with a single-point-of-failure risk (in the solenoid).

[DaveS]

This is what I am doing with my new build. My RO tank is 8' high and I just let gravity do the work. I use a JBJ ATO so it's timed. I also put a small ball valve to turn down the flow rate. At 7 minutes or whatever the limit is, it dumps about 1G of fresh water. Not an issue with a 300G system. My only failure point right now is the solenoid being stuck open. I'm considering putting a second one in series and having them both run off the JBJ. This way the both come on/off at the same time. Both solenoids would have to fail to dump more than 1G.

 

A little complicated but I'm not crazy about the Aqualifters as I've seen them flake out. Also, since my RO is 8' up, the whole siphon break thing was a pain. I'd end up with 8'+ of air filled tube that would have to bubble through my kalk stirrer before any water got through. That would just kick up more kalk power/precipitate sending it into my tank.

[Origami]

This is what I am doing with my new build. My RO tank is 8' high and I just let gravity do the work. I use a JBJ ATO so it's timed. I also put a small ball valve to turn down the flow rate. At 7 minutes or whatever the limit is, it dumps about 1G of fresh water. Not an issue with a 300G system. My only failure point right now is the solenoid being stuck open. I'm considering putting a second one in series and having them both run off the JBJ. This way the both come on/off at the same time. Both solenoids would have to fail to dump more than 1G.

 

Dave, a second solenoid is added protection from a probability point of view. But you'll have to make sure that you're able to detect a solenoid that's failed-open if and when it does fail so you're able to replace it.

[DaveS]

Dave, a second solenoid is added protection from a probability point of view. But you'll have to make sure that you're able to detect a solenoid that's failed-open if and when it does fail so you're able to replace it.

 

Whaddya mean? If it's working, why so I mess with it? You're right though- a periodic test by tripping the float valve on/off and listing for 2 clicks would be a smart thing to do.

[Origami]

Whaddya mean? If it's working, why so I mess with it? You're right though- a periodic test by tripping the float valve on/off and listing for 2 clicks would be a smart thing to do.

 

LOL. Yes, fault detection is an important part of gaining benefit from redundancy. You could also put a switch in line with, or simply unplug, each solenoid to periodically verify proper operation.