RO DI Unit

[stevil]

I did check out all his feedback and only saw 2 negatives... I should have done a bit more research I guess. I think the unit will be ok for maintenence fills, but not for the initial fill up.
Airforceb2 - how do you have your unit connected? I have the needle valve under my sink, but I also just tried to hook it up via the garden hose. The valve that hooks to the RO unit shot a water stream 15 feet away (at least), so I don't imagine that pressure is an issue. I didn't get any improvement in output with that method.
I will try doing the membrane flush and see if that improves output.

 

[chipmaker]

Originally Posted by Birdy
Just be aware that a faster flow usually means more impurities in the water, the faster the flow through the membrane the more stuff the membrane will let through. I would rather have slower flow and purer water than vice versa.
snip.
I asked this same question to a few online retailers, one auction site seller as well as three places here locally that sell RO/DI units, and they all made the same reply....Its a myth that a higher capacity membrane will filter out less than a lower capacity membrane. All thats made less is the quanity of water produced, not the quality of the water. If a membrane is made to flow "X" amount of water per day and designed to give X in TDS, why would a smaller membrane designed for 1/2 of X be any more efficient....? The belief has no basis.
There are more variables that will affect quanity of water produced and your waters input pressure, temperature and what it contians all play more in how well your system produces.

 

[airforceb2]

Originally Posted by stevil
I did check out all his feedback and only saw 2 negatives... I should have done a bit more research I guess. I think the unit will be ok for maintenence fills, but not for the initial fill up.
Airforceb2 - how do you have your unit connected? I have the needle valve under my sink, but I also just tried to hook it up via the garden hose. The valve that hooks to the RO unit shot a water stream 15 feet away (at least), so I don't imagine that pressure is an issue. I didn't get any improvement in output with that method.
I will try doing the membrane flush and see if that improves output.
Ok, this is what I did...it sounds like you have it backwards...
The supply line goes straight to the "IN" on the first filter. From the "OUT" to the check valve then to the RO unit.
Better yet,
Let me take a picture for ya...

 

[stevil]

Ah, that's not what I was referring to, I should have been more clear. I have my unit hooked up the same way. I was asking how you hooked up the supply side to the raw water source - with a needle valve or the hose connect. I'm assuming you get more pressure with the hose connect, which could increase the amount of water the unit processes.

 

[ezee]

Airforce
It took me 20 hours to fill my 90. That comes out to just under 100GPD if my math is correct. It takes a little while for the filter to start working at full capacity. Make sure you flush the membrane every so often. I flushed mine about ever 4 hours.
FYI, the sellers don't speak english very well so e-mailing was about hopeless for me. I had to do a couple adjustments to keep the leaks from starting but it only cost me about $8 at Home Depot. I still think the purchase was well worth it.
I seriously hope to have your experience. If I may ask, what did you have to adjust, teflon tape?
Thanks
E

 

[birdy]

Chipmaker- all I know is that the place I get my units from states on his website that the 75gpd has a higher rejection rate than the 100gpd.
I have tested the TDS from higher units and the ones with a lower gpd seem to have lower TDS. You have to test this before the DI unit as most good DI filters will take any TDS of water to 0.
I like to try things for myself and not just take a retailers word for it.

 

[newfishguy]

Honestly I don't like RO/DI units. I bought a 100 gpd one. Personally it takes too long to produce the water. 100 gpd is only 4 gallons an hour. It is easier for me to goto the drug store down the road and the get the water out of the machine for .25 gallon. I can get 5 gallons real fast. But that is just me. I still need to sell my 100 gpd unit. I bought it in July and only used it once.

 

[airforceb2]

Originally Posted by ezee
Airforce
I seriously hope to have your experience. If I may ask, what did you have to adjust, teflon tape?
Thanks
E

Yes, I had to re-tape the fittings and run them in tight. I also sealed the connections with silicone just to be sure.

 

[jerthunter]

OH NO! Not the leaky fitting game again!! I sure hope mine won't leak, I don't want more flash backs from the bad place.
Are the fittings flare fittings or do they require o-rings?

 

[airforceb2]

Half are compression fittings (I like these...they don't leak at all) and the other half are the "just push in and it wont leak ever again" fittings. These are the ones that require a little work. If the tube isn't sitting straight in the fitting, it will leak.

 

[jerthunter]

I just got my RO/DI unit and I have looked over it but I haven't installed it yet. I was curious how you set up the feedwater to the unit. I really do not like the idea of using the needle valve it comes with and piercing my piping like it says to do. Just curious if you have any better ideas that wouldn't require piercing the piping? I am planning on a trip to the hardware store to get something, maybe a threeway valve or something.

 

[lennon]

Originally Posted by airforceb2
Ok, this is what I did...it sounds like you have it backwards...
The supply line goes straight to the "IN" on the first filter. From the "OUT" to the check valve then to the RO unit.
Better yet,
Let me take a picture for ya...
Hey there. I am not sure where your unit is located..But can I attach to the laundry area so that the waste water goes into the washing machine??
That would at least make me feel better..rather than actually wasting that good water.
thanks

 

[airforceb2]

I took a couple more pictures but I can't post them right now. I think the boards are full from the photo contest going on. I'll try later tonight.

 

[jerthunter]

I got my ro/di unit yesterday but I just set it up today, unfortunatly I did not find any of the things that I wanted from the hardware store so I just set it up using the needle valve it came with and so far I have only had one problem (my own fault) caused by turning the needle valve until it pierced through both sides of the pipe, but a little rubber patch fixed the problem and now I am leakless. I guess I had a lot of luck because I didn't even have to use silicone or teflon tape. Of course now I see what people were saying about the flow rate, this would take forever to fill a tank.

 

[stevil]

Originally Posted by Jerthunter
...so far I have only had one problem (my own fault) caused by turning the needle valve until it pierced through both sides of the pipe

I did the exact same thing. I'm not sure what your plumbing is like, but I was able to replace the copper tube with a new one from home depot for about $3. It was very easy to install.
I'm curious what kind of output you are getting from your unit. Flushign the membrane periodically improves output, but I'm not getting much more than 6 GPD... if that.

 

[chipmaker]

They make an adapter thatfits standard faucets commonly found on kitchen and bathroom sinks........Piece of cake to install and you got lots of volumn unlike using the piercing needle type valves....... All you have to do is loosen the cold water supply riser and remove it from the sink faucet. Install the adapter where the nut originally held supply riser to sink faucet spud, run RODI supply line to this adapter. Cut off a portion of original supply riser and reinstall........if you get one of the flexible type grey risers its a peice of cake......but only a it more hassle with a chrome plated copper riser pipe, which is really somehting thats not seen much anaymore today since the advent of these flexible risers, which in my opinion are better anyhow.

 

[jerthunter]

Stevil- Well right now I am getting only about 1 gal per hour, I hope it goes upeventually, I am not going to mess with my unit for now but I suppose replacing the pipe would be a good idea in the long run.
Chipmaker - Yeah that was the idea I had but I could not find the right parts, maybe I was looking in the wrong section of home depot... I was suprised at how little they actually had, maybe I just need to buy a lathe and make my own.. ok, I'm not going that far, but I will try to find some good hardware so I can leave it and not worry about springing a leak.

 

[stevil]

Just curious how many Gallons Per Day (GPD) everyone's RO unit is and what kind of RO membrane you have. I believe this is the primary cause for the low output I've been experiencing. From my research on the web, a 125 GPD RO membrane must operate at higher pressures (100 PSI - 250 PSI), and a common household plumbing is around 40-50.
75-100 GPD RO membranes on the other hand seem to operate at the 50 PSI level, although there are some that require higher PSI.
This also explains why RO units can be sold as 125 or 100 GPD for the exact same housing and other filters - it's all in the membrane.
I don't believe there is anything specifically flawed with dvoneb's units, as a matter of fact, I think they are just generic housings that he slaps a sticker on since I've seen several others for sale elsewhere (although at higher prices).
So - for anyone out there considering an RO unit, make sure the RO membrane will operate at low pressures and still provide the GPD that you are expecting.

 

[jerthunter]

Wow, so I got a quick question about that, you said that both 100 gpd and 125 gpd membranes could fit into the housing? If this is so, would it be one of the 100 gpd membranes that operate at lower pressure?

 

[mavgi]

i have the same one i add the five gallon tank to it and connect it under my sink.
very happy with it. here some picture