Did I Plumb My Flush Valve Incorrectly?

[Adamantium]

Sorry if this is the wrong forum, but I'm having trouble figuring out whether I'm using a flush valve correctly.

I have it plumbed to bypass the pressure valve on the waste line. My in-line TDS meter, which comes out of the RO membrane (but before DI) shoots up to like 100 (tap is ~125) before slooowly climbing down to about 20.

Then, after closing the flush valve, the RO output slowly comes down to the appropriate 2-4TDS, over a few more minutes.

So, my question is, should I have installed the flush valve after the RO membrane, before the DI? It just seems like that makes more sense, since it would avoid having that high TDS water ever touch the DI.

Everything I've seen online seems to indicate it should be used to bypass the pressure valve on the waste line, though.

Any thoughts, or insights, would be greatly appreciated.

 

[lapin]

The flush valve goes on the exit of the ro cartridge. What it does is release the water pressure that forces the water thru the ro canister. This causes a big flow of water to pass over the membrane and not thru it. Thus flushing action.

 

[Adamantium]

The flush valve goes on the exit of the ro cartridge. What it does is release the water pressure that forces the water thru the ro canister. This causes a big flow of water to pass over the membrane and not thru it. Thus flushing action.

See, that's exactly what I thought, just intuitively, but if you look up videos, and instructions, they show it as being used to bypass the waste line. Any idea why that is?

 

[Adamantium]

The flush valve goes on the exit of the ro cartridge. What it does is release the water pressure that forces the water thru the ro canister. This causes a big flow of water to pass over the membrane and not thru it. Thus flushing action.

Wait, to clarify, the exit between the RO and the DI, or the waste line?

 

[lapin]

There are 2 exits of the ro cartridge
1 is waste and thats where it goes
The other is processed water and goes to your di. It does not go on that line.

 

[Adamantium]

There are 2 exits of the ro cartridge
1 is waste and thats where it goes
The other is processed water and goes to your di. It does not go on that line.

Ah! So, I do have it installed correctly. In that case, is it expected to have TDS shoot up so high when opening the flush valve? And then for it to only drop down to about 20 after like 10-15 minutes?

 

[lapin]

You should have no water coming thru your exit to the di cartridge when the valve is open. It will all exit out the waste line exit of the flush valve.
When you shut it you will see water starting to flow thru the ro membrane and go to the di cartridge.
This water can be higher in tds for a brief period if measured before it enters the resin
You could divert this water with a valve for a few min but the amount is so slight I dont see any reduction in the life of the resin.

 

[Adamantium]

You should have no water coming thru your exit to the di cartridge when the valve is open. It will all exit out the waste line exit of the flush valve.
When you shut it you will see water starting to flow thru the ro membrane and go to the di cartridge.
This water can be higher in tds for a brief period if measured before it enters the resin
You could divert this water with a valve for a few min but the amount is so slight I dont see any reduction in the life of the resin.

I do get a few drops coming out of the production line (having gone through the DI), but I guess it's so minor, it doesn't matter.

Maybe, just to preserve the DI as much as possible, I'll throw a valve on the line between the RO and DI to prevent anything from getting through, and then open it once things are flushed, and then close the flush valve.

Sound okay to you?

 

[lapin]

yep perfect

 

[Adamantium]

yep perfect

Nice. Thanks!