I need more PSI for my RO/DI

Loki · Mar 18, 2013

As we all know ideally we want 60psi for our RO/DI. At my last house I had 52 which was close enough for me. I just now setup my RO/DI and the gauge is reading 38psi.

So my question is are there any tips to optimize my psi that I can try before getting a booster pump?

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tomterreefic · Mar 18, 2013

Not sure how to increase pressure without pump. However, I added a permeate pump a few years ago and couldn't be happier with it.

http://www.amazon.com/gp/aw/d/B004BB47ZI/ref=mp_s_a_1?qid=1363662913&sr=8-2&pi=SL75

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fragmatic · Mar 18, 2013

Your water pressure will vary some according to how much water is being used in the house, how many homes are on the system, and what time of day. This has to do with lawn watering, peak shower times, etc.

As far as aiding at your RODI, if your water line runs very far you can try increasing the size of the tubing from the connection to the RODI system. If it isn't very far there is not much you can do about it. The reason increasing the size helps in long runs is because of line resistance. When a fluid runs through a line, velocity equals a pressure drop. So a larger line (tubing) has less velocity and therefore less pressure drop. Though you must realize this is not going to give you a huge boost when you are only talking about the volume per hour of the membrane and the bypass. If your line is really long it can make a difference though.

GratefulReef · Mar 18, 2013

+1 to all the posters above me. You will need a booster pump.

Loki · Mar 19, 2013

That's what I thought but I recently heard someone talking about turning up their pressure in the house. I didn't think it was possible but I knew if it was the people here would know

About this permeate pump. How does it work and where does it go?

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tomterreefic · Mar 19, 2013

The pump uses the pressure from your waste water to drive a diaphragm pump to increase your RO production. It can mount anywhere you want. I have mine on top of my RO unit. No electricity needed as it uses the waste water to drive the pump.

http://www.aquatec.com/permeate-pumps.html

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Reef Fever · Mar 19, 2013

dude mines at like 75 PSI and takes about 2-3x longer than it should, cant seem to get it to work right

AZDesertRat · Mar 19, 2013

Permeate pumps ONLY work in conjunction with a drinking water style bladder or pressure tank. They will not work without one. here are some FAQ from their site:
http://www.aquatec.com/sg_userfiles/FAQforPERMEATE.pdf
They use the stored up pressure in the bladder tank to drive the piston in the pump, otherwise they do nothing at all.

Without the pressure tank there is no pressure anywhere to drive the pump as it installs after the flow restrictor in the waste line so is open to atmosphere without the pressure tank as noted here in their installation instructions

"Locate the

"BRINE TO DRAIN" tube. it is extremely important that the flow restrictor is in front of (before)

the "brine inlet" to the Permeate Pump. The pump will not operate if the restrictor is in the "BRINE

OUT" line leading to the drain."

If you home is a new one, or even some older ones, look to see if it has a pressure regulator on the incoming water line, usually next to the shutoff valve or first exterior hose bib. Many municipalities require regulators but you should be able to adjust the diaphragm.

If not, check your pressure at different times of the day to see when it is highest. Often mid day when everyone is at work/school is a good time or late evening after all the bathing is done etc.

If none of the above applies then an Aquatec 8800 booster pump is your best option, really the only good option.

Loki · Mar 19, 2013

Ah! Now I have another question I have the storage container coming off of my RO only line. That won't help the permeate pump will it? It goes on the waste which is going straight down my drain.

I will check the valve a little later today.

Last night at midnight I had 38 psi this morning around 8am I had 36. Currently at 10:30am I am back up to 38 psi.

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Loki · Mar 19, 2013

So the permeate pump is only for upping the psi to put more water into my storage bladder?

I have a 3 gallon storage tank that (I believe) is around 60-90psi(?) if my water pressure is at 38 there isn't enough pressure to fill the storage bladder and will not be able to get the full volume out of the storage tank.

If that's the only use for it then I am not concerned with it. I would rather boost the psi going into the RO/DI to 60 to optimize the water usage.

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AZDesertRat · Mar 19, 2013

If you have a pressure/bladder tank it will work since it is hooked to both the treated RO and the waste lines.
here are the directions:
http://www.aquatec.com/sg_userfiles/IMI-106c.pdf

If you don't have a pressure tank it will not work.

OK, you last post says you have a pressure tank. The pressure in it will neve rexceed the 38 psi you have available, it cannot create its own pressure without a real booster pump.

All the permeate pumps do is reduce the amount of waste water by using some of the wasted energy to shorten the cycle time filling the pressure tank quicker. Systems with pressure tanks can actually have a waste ratio over 20:1 or more as the tank fills and the resistance is higher. By using some of that backpressure it balances things out. It will not raise pressure or anything else, just fill the pressure tank faster and reduce teh amount of waste water which is really a good thing.

Loki · Mar 19, 2013

Yes reducing my waste water is the whole goal.

I'm still unclear a little on the placement of the pump. My unit has two 75gpd RO membranes and a RO only output (for drinking) as well as the normal DI output.

I am using RO only for my drinking water and that goes into the pressurized storage tank. My DI goes into the two 55 drums in the garage.

So the permeate pump would have the waste line go in on one side and the RO on the other and then the RO would go to the storage tank. This will increase efficiency in the whole RO/DI and reduce waste even when I have the RO only closed?

Forgot to say that. I have heard that the storage tank needs to be shut off when I am wanting to make RO/DI water so that it doesn't push backwards through the unit.

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redfishbluefish · Mar 19, 2013

You need a booster pump!

I have the commonly found Aquatec 8800 that I picked up from BRS for $140

However, there are other no-name brands that are considerably less:

HERE’s one from Filter Direct for $85.

And yet another example HERE from ebay for $64.

What’s important is that you match the pump to the gph membrane you have.

That will fix your problem.

AZDesertRat · Mar 19, 2013

Stay away from the generic pumps, they are less expensive for a reason. Quality costs money and its not that much more for the industry standard Aquatec pump, it will probably outlast the others by several times meaning it actually costs less over time.

shovelrider · Mar 22, 2013

If you own you home or rent a house that usess city water, there will be a water pressure regulator outside that attaches to the city line. You can adjust pressure with this easily. If it is an old house, take care so you dont burst your lines by over pressurizing.

AZDesertRat · Mar 22, 2013

Pressure regulators are not that common, usually only in newer areas or where pressure zones are not laid out well. You rarely see them in the west. If you do have one on your incoming plumbing then it is an easy thing to screw the diaphragm in further though.

mc-cro · Mar 22, 2013

how are you feeding the ro/di unit. 35psi sounds very low for house pressure, doesnt it have to be higher than that by code or regulation or something?

I had a very similiar problem when I moved into my new house. the pressure at the unit was too low, around 3opsi. after tons of troubleshooting, I discovered that the piercing saddle valve I used for the feed line didnt properly pierce the line all the way. when I backed it out and redid it, I got the pressure I needed

Loki · Mar 22, 2013

I have a split from my washer line. No piercing or anything. It sits at 38.

The house is about 5 years old so I need to find the incoming water and mess with it I guess. I've heard that if the valve isn't open all the way it could be restricting the pressure.

I haven't messed with it at all in the last few days. Been busy moving other stuff over and haven't had a chance.

I won't be able to mess with it again until Tuesday.

This is a new subdivision and they are still building houses in it. I'm on city water and am hoping its just done easy tweak/fix instead of having to buy a pump.

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AZDesertRat · Mar 22, 2013

38 psi meets most codes. Around here is is 40 psi normal and 20 psi during fireflow events or maximum demands. Not ideal but its what it is. Mine is usually 68 though even in peak summer months except early in the morning and around 9-10 PM when everyone is bathing.

fragmatic · Mar 22, 2013

A valve being partly closed is not going to effect static pressure. It will only effect the pressure to your RODI if you are really running a huge RODI. At the volume of fluid you are moving the pressure drop will be slight and may even be not detectable. How much water are you getting out of your RODI? Fill a 1 cup container and time it. Then tell us how much it would be per hour.

There is another aspect. If your 1 micron filter is in the first canister by mistake without a sediment filter (or two) of some kind before it, it will clog up really fast and your water flow through the RODI will drop to near zero.

I've seen people put a common slip fit ice maker filter in the tubing before the RODI to catch more trash, and it adds life to the RODI filter cartridges. Those ice maker filters are cheap and change really easily. Our city water is so heavy with sediments I had to put ice maker filters in the lines before every one of our toilets so the darn fill valves would last more than a few months... and that was the last time I had to replace those fill valves.