RO flow rate/pressure

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
ggcadc
Posts: 66
Joined: 13 years ago

#1: Post by ggcadc »

I'm looking at an RO system (tankless with a pump) for a built in coffee bar in our new kitchen. I'll have a bar sink and I'm wondering if there's a known good system that flows enough to use a regular faucet. Since it will be a small bar sink I don't necessarily want to have two separate faucets. I know with my old tank RO system the flow was extremely low and this wouldn't be possible.

Are there good known systems that accomplish what I'm looking for?

Nunas
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#2: Post by Nunas »

Nearly any RO system will do, providing you don't use the accumulator tank. In yachts, desalination systems, which are just RO systems running at higher pressure, dump the product water into non-pressurized tanks. The water is delivered to ordinary faucets with pressure pumps. So, you could easily do this using a stock, generic under the counter RO system, into a tank, with a float switch to cut off the RO when full (like on toilet cisterns). The product water could then be delivered with any small pressure pump, such as those used in RVs and yachts.

prust
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Posts: 56
Joined: 6 years ago

#3: Post by prust »

The home systems that use a pump have a very limited flow rate. The flow rate also decreases as the temperature of the water in goes down in the winter. The ones I researched were up to 600 gallons/day under ideal conditions. I purchased one rated at 500 gallons/day and in reality, it takes puts out 1-2 quarts/minute. If you are connecting this up to a plumbed in machine, you need a separate pump to increase the pressure. If you want to use it as a faucet for cleaning and water for a machine tank, the flow rate will be very slow. Hope this helps.

_Ryan_
Posts: 183
Joined: 3 years ago

#4: Post by _Ryan_ »

Nunas wrote:Nearly any RO system will do, providing you don't use the accumulator tank. In yachts, desalination systems, which are just RO systems running at higher pressure, dump the product water into non-pressurized tanks. The water is delivered to ordinary faucets with pressure pumps. So, you could easily do this using a stock, generic under the counter RO system, into a tank, with a float switch to cut off the RO when full (like on toilet cisterns). The product water could then be delivered with any small pressure pump, such as those used in RVs and yachts.
I had an RO setup at home using a Dow filmtec membrane and a few stages of carbon. I ran it into a 8l 'dispenser'(counter top water holder/juice jar) then dispensed water from there. This overcame the flow rate when I'd want 1.5l to fill the espresso machine, or 1l for my water bottle.

If I were plumbing RO only for a coffee machine, I'd run mains > prefiltering > RO > remin > holding tank with float valve > espresso machine.
But I'd personally probably avoid plumbing RO unless I could be sure of remineralisation content.

The challenge I foresee, if my understanding of remineralisation cartridges is accurate, is that you'd want to discard the 'start' of the flow for consistent mineral content.

As a point of reference, my RO membrane was of the below specs, it would output around 8l in 30-35 mins from our weak mains pressure via a diverter valve on a faucet.
This 4 stage counter top reverse osmosis system has the following flow rate: 100 GPD/ 400 litre per day genuine Dow Filmtec membrane @50 psi, 600 LPD @ 100 psi