DI Bypass Query

[Reaf]

Currently have a standard vyair RODI unit that has a flush valve, how long should I let this run for before and after use?

Also from what I have read on the forums I should add a bypass before the resin as well, would you close this bypass whilst having the flush valve open?

 

[KStatefan]

I do not use a flush at all. I bypass the resin for a couple minutes at startup to move any TDS creep to the drain.

 

[homer1475]

Ideally you need a TDS meter to determine how long to flush for. I usually set a time for 5 minutes, long enough for my system(I go from 24 incoming, down to 3 before I start making water).

And yes you would close the valve, or send all water to waste when flushing the unit. The idea is so that even though you are flushing the unit(sending low pressure water over the membrane to clean off scale), you are still sending some high TDS water into your DI. With the valve installed, you shut the DI canister off, and send that small bit of water down the drain.

Is it necessary, no, but it helps prolong the life of your DI resin.

 

[Reaf]

Ideally you need a TDS meter to determine how long to flush for. I usually set a time for 5 minutes, long enough for my system(I go from 24 incoming, down to 3 before I start making water).

And yes you would close the valve, or send all water to waste when flushing the unit. The idea is so that even though you are flushing the unit(sending low pressure water over the membrane to clean off scale), you are still sending some high TDS water into your DI. With the valve installed, you shut the DI canister off, and send that small bit of water down the drain.

Is it necessary, no, but it helps prolong the life of your DI resin.

Thanks What's your process for flushing new filters and membranes?

 

[homer1475]

Same as above.

With the DI bypass valve, you can send any water coming out of the unit down the drain.

DI does not need to be rinsed before use.

 

[Reaf]

Same as above.

With the DI bypass valve, you can send any water coming out of the unit down the drain.

DI does not need to be rinsed before use.

Is flushing sufficient for new filters and membranes as I have read some people produce several gallons through the new filters and membranes which are then tossed before starting again afresh

 

[homer1475]

I personally let my TDS meter, and pressure gauge tell me when to change filters. RO membranes last a few years before they need replacing.

And yes flushing with a DI bypass valve is a perfectly acceptable way to rinse new filters.

 

[homer1475]

My current RO/DI unit is going on 15 years old. Think I have replaced the RO membrane once in that time.

If you measure TDS, you know when to change the membrane. When the rejection rate drops, it's time to change them. Never bought into the hype about changing them every so many gallons.

 

[Gatorpa]

My current RO/DI unit is going on 15 years old. Think I have replaced the RO membrane once in that time.

If you measure TDS, you know when to change the membrane. When the rejection rate drops, it's time to change them. Never bought into the hype about changing them every so many gallons.

At what level of TDS do you change the membrane, i’ll looked on here but haven’t found a number yet

 

[KStatefan]

At what level of TDS do you change the membrane, i’ll looked on here but haven’t found a number yet

I change mine when rejection rate is below 97%. The TDS will vary depending on source water

 

[Biglew11]

Same as above.

With the DI bypass valve, you can send any water coming out of the unit down the drain.

DI does not need to be rinsed before use.

I use 3 stages of di
Cation, anion, and mixed bed. I find that when I change out anion I have to flush it unti I get 0tds out of it. About 5 minutes usually.

 

[Mike konesky]

I use 3 stages of di
Cation, anion, and mixed bed. I find that when I change out anion I have to flush it unti I get 0tds out of it. About 5 minutes usually.

Good idea to flush resin before it's first use. Here is some brs pro cation being flushed. No idea what this is but I'd sure like to know.

 

[Biglew11]

Good idea to flush resin before it's first use. Here is some brs pro cation being flushed. No idea what this is but I'd sure like to know.

Definitely looks like something I do not want in my fresh rodi water.