Reverse Osmosis to Pre-Plumbed Ice Maker/Refrigerator Loop

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yesngo

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My kitchen has a pre-plumbed 1/2 in loop under the sink presumably leading to the refrigerator ice maker line. What's the best way to hook up a reverse osmosis system to this? Since all the lines from the RO system seem to be 1/4 in, it seem to me like change from 1/4 in to 1/2 in would result to too much of a loss in water pressure.

I was thinking of using a 1/4 push connector (like a sharkbite fitting) to the pipe, reducing it to 1/4 to the RO system, and then the reverse when it leaves the RO. Will the push fittings work on the tubing that comes with the RO system?
 

ditttohead

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It is typically copper. The best fitting for this is a simple 1/2" compression by 1/4" angle stop, and a 1/2" compression by 3/8" compression angle stop.

The 1/4" would go on the inlet, the 3/8" would go on the outlet for higher flow to the refrigerator. This is very common on modern houses and makes RO installations very easy.

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yesngo

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Yes, it is copper. So the output line from the RO can accomodate either a 1/4 or 3/8? I have not yet purchased the system, but all the instructions I've been reading online seem to indicate the output tubing is 1/4 inch. I'm assuming I could get an adapter to go from the 1/4 up to the 3/8.

When the 3/8 tube outputs back into the 1/2 pipe, is there going to be a problem with the amount of pressure the refrigerator needs to make ice?

Finally, do you know if the compression angle stops come in the push fitting type (like Sharkbite) or would I have to use a push fitting first and then screw on the compression angle? Thanks for all your help.
 

Reach4

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You may want to re-plumb the output of the RO to the ice maker with polyethylene. I suggest that you do a search engine search on "RO system" copper
 

yesngo

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Hmm, just did a quick search on copper with RO system and I see there is definitely some controversy regarding the safety of RO on copper pipes. Seems strange to me that the house would come pre-plumbed if this is a known issue. Are they assuming we would be using just an in-line filter and not go as far as a RO system? I'll definitely have to read more into this.

BTW, I see that sharkbite does make the compression angle stops, so I could use those if I plan on proceeding.
 

Tom Sawyer

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Copper to an ice maker ain't going to cause an issue unless it's a commercial unit. Otherwise a residential ice maker doesn't use enough water for it to be an issue. Get a couple of compression x compression couplings and have at it.
 

ditttohead

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I highly recommend an RO with a Permeate pump if you are going to feed an ice maker as well as 3/8" final tubing. The inlet tubing is almost always 1/4"

Tom is correct, a standard residential RO will usually produce a high TDS RO Water. Commercial high pressure RO systems can reduce the TD to below M, a residential RO is usually 5-10X that much TDS.

If you are concerned, a simple remin filter is not a bad idea, it adds a little mineral taste to the water and raises the pH above 7. http://www.impactwaterproducts.com/#!5-Stage-RO/zoom/c1wv2/image18qp
 

yesngo

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So if I understand correctly, you want the RO system to work pretty well, but not THAT well. The more it reduces the TDS, the greater the chance it will harm the copper pipes. Does that sound about right? It seems a little strange to me to take out the minerals and then have to readd them, but I'll definitely keep that option in mind.

Do you think that if I go with a RO without the permeate pump that I'll still have enough pressure at the refrigerator if I use the 3/8 outlet line? I don't plan on having a faucet at the sink at all. It will all be piped into that 1/2 copper pipe going to the refrigerator.
 

Tom Sawyer

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Generally, I don't like to use RO for mineral removal. It's a very inefficient use of water. The usual reason is to remove other contaminants that media filters won't remove or the cost is too high.
 

Tom Sawyer

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Addendum, and minerals in quantity greatly reduce the life of the RO membrane
 

ditttohead

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It will probably be fine, but... add the permeate pump. They are not that expensive, save a lot of water, increase the storage capacity, and increase the water pressure feeding the appliance. The 3/8" is only on the product line from the tank to the outlet, the inlet side is 1/4". A standard RO only makes 1-2 gallons per hour, the flow is derived from the storage tank to the faucet/appliance.
 

yesngo

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Sounds like the permeate pump is definitely worth its price. Do you have any recommendations regarding the ERP 500 vs 1000? Should I keep the shutoff or remove it? I'm thinking if TDS creep happens, that's not such a bad thing, as it may help protect my copper pipes.
 

ditttohead

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TDS creep is not understood by most. It is rarely detectable except in cases where the RO water use is very low. Do not bother with an ASV. The 500 is for up to 50 GPD systems, the 1000 is for up to 120 GPD systems. The 500 is much quieter than the 1000. The 1000 makes a noticeable "click" that bothers some people when it is installed under the kitchen sink.

Hope this helps!
 
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