RO/DI units

[ballardjr2000]

Ok i know what and the importance of RO/DI units are etc. what i don't understand is i see some with pumps and some without. now the question is do you need a pump with all of them. or do some work of the normal pressure from say a garden hose fitting etc.

[Jonthefishguy]

Pumps are used to increase the pressure if your city water pressure is too low and needs a boost. The unit does not work efficiently if the pressure is too low.

[ballardjr2000]

Ok got it. so one may or may not be needed all depending on water pressure of the source. well i look at it like 4wheel drive better have and not need then need and not have. lol

[dipan]

Another good reason to have a booster pump is to increase pressure to the membrane. It can be setup so that it keeps 80-90 PSI at the membrane. That is, after the sediment/carbon block prefilters, where some pressure loss will occur. The booster will also maintain your water pressure and consequent efficiency even if you're flushing a toilet, taking a shower, watering the lawn, etc. when some pressure loss will happen even if your static water pressure is good ...

A good idea, IMHO ...

[Squiers007]

Not to thread jack, but what pressure do you want to maintain and what would be the low end cutoff to where you would want to consider a pump? Thanks.

[TexasRedneck]

Generally speaking, minimum water supply pressure for small (20-50 gpd) RO systems is 40 psi. Higher pressures ARE helpful - but I'd be VERY reluctant to install such inside a home! Generally speaking, the types of fittings usually used are pretty cheap, and consequently leaks are not at all uncommon. Personally, I prefer ANY RO system to be located in the garage in an area where leakage can occur without causing damage - because sooner or later , it WILL leak - period.

Look at the average small RO, and count the connections - the average connection has at least two leak points - the threaded part and the part where the tubing or piping connects. The push-type connections commonly found are, IMO, some of the worst offenders - but manufacturers love 'em because they're cheap and assemble fast, makin' labor costs lower. The fact that they leak in a couple of years isn't their problem - but at this time, no one is using the better-quality fittings because to do so would put their price points too high and folks won't buy them.
They also make a inlet valve that installs inline (1/4" tubing in/out) and mounts on the floor, and if a leak occurs it shuts the water supply off. They run about $20-25 and aren't reusable (if they "trip", you have to replace them) - but it's cheaper than water damage!

[dipan]

I'm gonna have to disagree with your put-down of John Guest type fittings. I've never had one leak in over five years and four RO systems ... Small sample size, probably, but these fittings are solid ...

That said, I do think it's a good idea to put them in a garage if possible ... just in case.

[txav8r]

John guest fittings pass the federal aviation administration standards fir use I. Pressurization fittings but only up to 18 psig. Just a little info. Not taking sides.

[TexasRedneck]

No offense taken - after all, we don't know each other, so there's no way of knowing background. I've been doing water purification and treatment since 1976 - everything from softening to ultrafiltration. I've designed and installed everything from plating shops to pharmaceutical systems. I've screwed up by the numbers, too - I am an Honors Graduate of the University of Hard Knocks!

I currently have about 5-600 RO units out - everything from 1,000 up to 100,000 gallons per day. The RO's are commercially made (IOW, no - I don't make 'em), but I've been involved with redesign of 'em over the years. I don't say all this to boast, but rather to give you an idea as to my background and where I'm coming from - because yes - I DO tend to "overbuild". So I try to be cautious when I approach something designed for residential use, and remember that it's not made to be nearly as robust as a commercial unit. That's why I said that while I don't like 'em, pretty much everyone uses 'em.

I see a lot of them fail - not when new, but 2-4 years down the road - because I service some residential units with the fittings on them, and I can ASSURE you that the failure rate is significant enough that they'd never go on a unit in my house - but bear in mind that I say that knowing I'd spend a good 20-30 bucks in fittings and several hours labor by the time it's over and done with. But, that's fine for ME - it's worth it. Most folks don't consider it to be worth it, and that's okay too - it's their house!

Generally speaking, when I'm working with JG fittings and removing/replacing tubine, I replace the fitting as well. Overkill? Maybe - but remember that they seal because of an o-ring which WILL compress over time - so taking the tubing out and reinstalling it will often result in a leak, and I hate going on a "call-back"!

[mikedelgado]

what type of fittings do you replace them with?