Automatic RODI Flush and ATO which eliminates TDS Creep - DIY Solution

sgrosenb · Oct 1, 2018

Hi there,

I've got a possible DIY solution for an auto top off which eliminates TDS Creep. The diagram below shows my thought. Basically it's a dual solenoid - the first one opens for a few minute to flush the system, then the second one opens (and first one closes) and you have clean DI water for the tank. The top-off at the thank is merely a float switch. Anyone see any issues with this? I'm not well versed on RODI but I do know that pressure and on/off/on/off needs to be minimized. This also has a drinking water component, although I don't think that will play in to it much. Any help is appreciated. Thanks!

-Scott

Ranjib · Oct 2, 2018

I like it, thanks for sharing. Would love to see how this performs in field test

. Not a plumbing expert, but I was wondering if theres any thing for safety. I would start with contemplating how things will unfold if each of the solenoid fails

KStatefan · Oct 2, 2018

This is my DI-bypass system but not tied in to auto top off just my storage container.

sgrosenb · Oct 2, 2018

Nice thanks KState and Ranjib. KState - do you have a quick list of components in there? looks like a few solenoids and a controller of some sort? Thanks! Also any other info would be helpful. Appreciate it!

KStatefan · Oct 2, 2018

Tank Level Controller
Delay Relay
2 NC solenoids

dmolavi · Jan 3, 2019

what brand of solenoid is that? (or, where did you buy it?)

KStatefan · Jan 3, 2019

dmolavi said:
what brand of solenoid is that? (or, where did you buy it?)

I think they came from Buckeye Hydro

sgrosenb · Jan 3, 2019

Both mine are tunze I got from aquacave https://www.aquacave.com/tunze-solenoid-water-valve-8555-200.html. Also - on my tank, I use a Liquid Level Controller from SpectraPure https://spectrapure.com/Single-Tank...er-115VAC&filter_name=liquid level controller. Just an update to this thread - I have had this in place for a few months and it is working great.

dmolavi · Jan 3, 2019

Those are Tunze? They look nothing like them. I'm wondering how they are compared to the DC ones from autotopoff.com

sgrosenb · Jan 3, 2019

dmolavi said:
Those are Tunze? They look nothing like them. I'm wondering how they are compared to the DC ones from autotopoff.com

nah I think the ones KState mentioned are different - mine are not pictured but this was my original post with the diagram

dmolavi · Jan 4, 2019

Thanks. I think I'll pick up some from autotopoff.com and use a pi-zero for control (maybe link to reef-pi once I get that up and running).

HouseofStark · Mar 16, 2020

I am trying to do the same setup, but I use a booster pump. I am having an issue with "auto shutoff pressure" switch seeing enough pressure to shut off. I have the pumps on/off pressure switch after the ro membrane and before TSDS flush solenoids....which does shut down the pump off after production has reached full level, but then I can see/hear the 4 way diaphragm pressure switch still letting water run down waste side off RO membrane. Any suggestions ideas? The only way I can get it to stop is, leaving the DI production solenoid on past shut down....and let water pressure build all the way back to the diaphram.