Questions about RO Systems


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Old 09-24-16, 08:51 AM
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Questions about RO Systems

Putting in a 75GPD RO system in the downstairs kitchen.
input - Well pump pressure 40-60 PSI from water softener system.

1. Can I run a 30' extension hose to the upstairs kitchen to a point of use faucet from a tee in the line? (3/8" diameter line)

Usage would be the same. I'd either use upstairs or downstairs not at the same time.

2. If so, should I put in a larger than included 4 gallon storage tank to maintain pressure, or would I need a delivery booster pump?

3. Water softener has a sediment pre-filter, do I still need a 5 stage RO system or will 4 stage be OK?
 
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Old 09-24-16, 09:44 AM
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You can run a long line from the outlet of the system. Pressure at the outlet of the system will be about 2/3 of the incoming pressure, at best. Then you will lose at least 5 psi due to the elevation change to the second floor, plus loss due to friction in the line, fittings, etc. So I think you will find you will need a booster pump to get any kind of decent flow on the second floor. And undersink R/O systems, for the most part, have pretty low flow to start with. Some are better than others. Increasing the size of the storage tank won't really help with increasing pressure or flow.

I suggest you use PEX or copper for the long run and consider using at least 1/2 inch to minimize losses. I don't like to run that thin wall PE tubing through walls and such; just don't trust it.

As for the sediment filter, I suggest you compare the specs (particle size) of the R/O pre-filter with the one you have before the softener. If the softener pre-filter is at least as fine as the R/O pre-filter than you can skip the R/O pre-filter. The pre-filter helps extend the life of the R/O membrane, but it also adds pressure drop.

Good luck with your project!
 
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Old 09-24-16, 10:45 AM
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I have my RO system located about 30 feet from the points of use. I ran 1/2" PEX for the long run but the system is still limited by the 1/4" fittings at the pressure tank and pure water tap in the kitchen. Still, the larger line does help cut the pressure loss. If you find that the pressure at the faucet is not as good as you'd like they to have electric booster pumps that will improve the flow.

As for the pressure/accumulator tank... how much water do you use at a time? If you are just filling a coffee pot and a water bottle in a half hour period then your system will be more than adequate. If you fill a large stock pot with RO water then want to fill drinking glasses for a dinner party the flow will noticeably slow and you may want a larger tank.
 
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Old 09-24-16, 01:15 PM
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I would make a test run with the 30' tubing and see how the pressure is. I think it might be fine if all you want is faucet.
Granted you are going vertical, but look at a typical horizontal run and how much tube it takes:

- maybe 8' over to fridge
- 5 to 10' coil behind fridge

Let's call it 20' and the pressure at the fridge is sometimes very good in situations like this.

If you want to go in the walls, use copper if 3/8" is allowed in your area. 3/8" soft copper is compatible with the push in fittings.

Edit: Here's a tip I tell some of my customers:
If your upstairs pressure is good for filling a glass, but takes too long to fill a pot, most filter faucets can stay open.
Lift up on the handle and it will lock open until pushed down.
 

Last edited by Handyone; 09-24-16 at 01:42 PM.
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Old 09-24-16, 04:02 PM
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Thanks for the quick replies.

1/2" PEX great idea. I wasn't too keen on the thin stuff that long of a run either.

I'm going 25' over and 5' up, so I'll give it a try before ordering the pump.

The water softener sediment filter is 25 micron and the RO units are 5 micron so I'll leave them in place.

We use about 5 gallons a day for drinking/cooking.
I'm assuming that the 4 gallon tank will only hold about 2 gallons or so of water. Correct?
Is it more efficient (less waste water to make RO water) to draw out 2-3 gallons in jugs at a time or just by the glass full.

My understanding is that the lower volume of the depleted storage tank produces a more efficient process as opposed to topping off the tank.
Or am I being too anal about efficiency and the amount of waste water processed?
I'm so used to having gallon jugs in the fridge and on the counter, and
I really hate wasting water.

The water taste OK after the water softener, but the TDS is 763 that's why the RO filter anyway.
 
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Old 09-24-16, 05:06 PM
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Water waste is the main reason I don't like whole house R/O systems, especially on a well. But for cooking and drinking water the waste isn't that bad. Amounts to a toilet flush or two a day.
 
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Old 09-24-16, 05:18 PM
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I only reconnect systems or install them for customers as a favor. I'm not familiar with the water quality.
From what I understand, at least 3 to 4 cups of water will be drained for every cup filtered.

I have heard of numbers 3 times that, but that's probably commercial quality systems.
 
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Old 09-24-16, 06:14 PM
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OK thanks everyone.
Should be here next week.
I'll report back.
 
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Old 10-09-16, 09:32 AM
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Just wanted to close by saying everything is working great and thank you all for the help.

I installed an I-Spring 5 stage 75GPD system, and it's like drinking bottled water.
TDS went from 763 to 25 ppm.

I'm a little disappointed with the waste rate of 7:1 (measured) as compared to the manuals claim of 2:1, but it's still better than buying 150 gallons of drinking water a month.

I gave up on the second floor line because of the max 15' hose recommendation in the manual.
A booster pump and larger storage tank is just not economical for the convenience.
 
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Old 10-09-16, 09:45 AM
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Good to hear it is working for you. Thanks for the update!
 
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Old 10-09-16, 02:09 PM
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I got my booster pump off Amazon and it was much cheaper than the one offered by the RO company. I went the first 6 or 8 years without it so it's something you can add in the future.
 
 

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