More RO/DI questions

[ellisz]

Hi all,

I recently did an over haul of my RO/DI unit. I bought an Aquasafe Canada unit 3 years ago. I added a Dual DI unit and got rid of the DI unit that came with it 2 month ago. I replaced the Applied 100 gpd membrane with a 75 gdp filmtec unit 3 weeks. The membrane housing had what appeared to be an metal restrictor on the membrane housing. I removed the guts of this and added a 75 gpd inline restrictor. I have collected about 150 gal of filtered water in the last 3 weeks too,

I had been getting good results but after doing some calibration on the TDS meters, I am wondering about these findings.

Readings are from a Hanna TDS1 calibrated with 342 PPM solution.

Incoming water: 242 TDS
Post RO: 70 TDS
Post DI: 7

Post RO TDS per the DM1 Dual inline TDS that I swear I calibrated was 40. Not very accurate ...

Now I am pretty sure my DI is exhausted as it has color changed from blue to brown. I have some DI beads on hand. I don't like the Post RO number though. Could the restrictor not be correct? It was only $2.99.

I am flushing the the membrane now. I am using a lot more water now than in previous years. Will the flush take care of the issue or do I need to do some more digging?

Thanks

 

[Colin]

That thing you removed was most likely a check valve. It needs to go back on. The flow restrictor is a plastic piece, probably clipped on to the frame, right before the output. Mine has a big handle on it.

Your post RO is waaaay to high. Something is wrong. It's burning through your DI resin.

HTH,

--Colin

 

[Spuds725]

Yep-- your RO out (with that membrane) should be about 5 ppm (10 max if you are running a low feed pressure)

 

[ellisz]

I knew the RO out was messed up, hence the post

What would be the use of the check valve? I have read that some of the flush kits have the restrictor built in? I do have the flush valve with the handle on it. You only turn it when you want to flush the membrane though. I am wondering if I have 2 flow restrictors in the unit now? I also have the auto shut off. I can't really find any info on the specifics for this unit ...

Thanks

 

[Colin]

The check valve keeps water from flowing backwards. They're especially important if you have a tank or some sort of float valve attached.

That flush valve with a handle is also a flow restrictor. Remove it.

--Colin

 

[ellisz]

I just found out about the check valve! I need to keep the flush valve though. I guess I need to take it apart and see if there is a flow restrictor in there...

I am assuming that I need a flow restrictor in there rated for my membrane? Is this not the case?

I am going to order a new check valve and auto shutoff as a maintenance precaution. Cant be too safe. I just to make sure I have everything I need.

 

[Colin]

I have an AquaSafe unit, trust me, there is a flow restrictor in there. The easy thing to do if you want to flush is just disconnect or bypass the flow restrictor. That has the same effect. You really should pull the second flow restrictor out of the system.

--Colin

 

[ellisz]

I put the check valve back in and removed the inline flow restrictor. I have the DI bypassed right now as the TDS is still high coming out of the RO. It is getting lower so I am just running the water in the sink to see what happens.
I guess I can remove the flush valve and add the inline flow restrictor to see what the TDS does.

Have you replace the membrane in your unit?

Thanks for the help.

 

[Colin]

Yeah, I put a 75G/day membrane in mine and got an adjustable flow restrictor so I can adjust for seasonal temperature variations.

Good luck, let us know how it goes.

--Colin

 

[Colin]

Oh, and be sure to use the 75G/day flow restrictor! The one that came with it won't work properly for a 75G/day membrane.

--Colin

 

[ellisz]

Well, I have tried it both ways ...
I removed the 75 gpd inline restrictor I bought with the membrane and just used the one in the flush valve ... Post RO numbers are still in the 50's.

I removed the flush valve and and just used the 75 gpd inline restrictor and the TDS got to the 40's after running for about an hour!

Stupid question: I put the inline restrictor where the flush valve would be ... this is on the waste water out put line. Is this correct?

I currently have the 75 gpd restrictor out and am flushing the membrane again. This is frustrating!

 

[ellisz]

I put the restrictor inside the waste drain tube line and turned it on again. Post RO TDS was 50 again. It had went to 25? I also noticed the was from the Post DI line is coming out faster than normal ...

Maybe the restrictor I have is not correct...

 

[Colin]

Try re-seating your new membrane. Maybe it's not quite in right.

The restrictor should be the last thing before the waste water output, and after the auto shut off valve. What kind is it? Do you have a link to where you bought it?

--Colin

 

[ellisz]

It is a capillary style restrictor. I have it right at the membrane housing. I will move it after the shut off and see what that does.

I think I might have messed up the check valve too. Did you replace anything else when you did yours? I wondered if replacing the auto shut off and check valve might be a god idea too.

 

[ellisz]

The auto shutoff is only connected to the water feeding the membrane and the water coming out of the membrane to the DI. The restrictor is inline of the waste water output. So it sounds like it is all correct. I basically removed the flush valve that came with the unit and put a Guest fitting coupler. I put the capillary restrictor after the coupler. It is a small piece that fits inside the water tubing. It then slips into the coupler with the line.

I did pull the membrane out and based on how hard it was to get it, it looked to be seated well. It is all back together now and bypassing the DI to run some water through the membrane.

Thanks

 

[Colin]

What's your waste water to product water ratio? You can check it with measuring cups. It sounds like everything is hooked up right. The only thing I replaced was the flow restrictor.

--Colin

 

[ellisz]

I filled a 1/2 cup measuring cup with waste water in 17 seconds. My RO output filled it in 30 seconds. I seem to have too much water running through the membrane right? I have pulled it out twice to make sure it is seated properly. The membrane is only 2 weeks old

 

[AZDesertRat]

It probably is still not inserted far enough. They go down past the lip of the housing so you will need something to push it in the rest of the way. I use a small block of wood myself.

 

[ellisz]

I had read a previous post that you had said this very thing. Mine is flush with the housing. I felt like I would have to hammer it to go down farther. I'll try again.

Thanks

 

[ellisz]

Alright, I took a small piece of wood and smacked it down with a large wrench. It might have lowered a bit but not much. The RO output is now at 38 TDS according to the DM1 which is probably around 50 on my TDS1 hand held. I calibrated both meters but the DM1 is pretty inaccurate.