View Full Version : 3/8 water line for 60 psi
Moosetracks
10/10/2016, 10:22 PM
when I put my RO system together I used tubing purchased at lowes. I used some 3/8 vinyl tubing for the long distance runs to help with flow from my storage tank. Recently I added more stuff to my system and I noticed a few of the 3/8 lines were leaking. I used push to connect fittings everywhere. When I took them apart the 3/8 clear tubing was a cloudy white and hard where it went into the push to connect fitting. I know this tubing is not rated for plumbing pressures but I figured with ro it would work ok. Now I'm thinking that when the ro system is full the pressure must climb too high for the tubing. I looked around but most of the 3/8 push to connect tubing was around 40 psi.
What do you guys recommend for tubing so it won't degrade over time?
uncleof6
10/11/2016, 01:12 AM
Low Density Polyethylene is possibly the most common type of tubing used with RODI systems (no data to support that.) Linear Low Density Polyethylene tubing is probably the best choice. LDPE is more flexible, however LLDPE tubing is recommended for use when stress-cracking is going to be a problem; LLDPE is recommended for use with push on fittings, such as John Guest and imported knock-offs. I am not going to try and guess why your tubing failed; but I don't have much faith in anything from Home Depot or other big box stores.
You are right, however, 3/8" vinyl tubing (pvc) max working pressure is ~55psi. The max working pressure for LDPE is 90psi; and the max working pressure for 3/8" LLDPE tubing is ~108psi.
https://www.h2odistributors.com/pe-12-ei-0500f-b
bblumberg
10/12/2016, 05:47 PM
when I put my RO system together I used tubing purchased at lowes. I used some 3/8 vinyl tubing for the long distance runs to help with flow from my storage tank. Recently I added more stuff to my system and I noticed a few of the 3/8 lines were leaking. I used push to connect fittings everywhere. When I took them apart the 3/8 clear tubing was a cloudy white and hard where it went into the push to connect fitting. I know this tubing is not rated for plumbing pressures but I figured with ro it would work ok. Now I'm thinking that when the ro system is full the pressure must climb too high for the tubing. I looked around but most of the 3/8 push to connect tubing was around 40 psi.
What do you guys recommend for tubing so it won't degrade over time?
+1 on LLDPE. I used LDPE tubing from Lowes from my RO to the tank (I used to refill my discus tank overnight after changing water) and woke up to 3" of water in my downstairs one morning due to the tubing splitting. I have never had a LLDPE tube split, although, I am cautious enough now to keep the RO unit and tubing outside and pump the water in from a storage barrel!
Buckeye Hydro
11/01/2016, 03:03 AM
Yep - the clear vinyl (PVC) tubing is not intended for use in the john guest style fittings. You need a rigid walled tube like the LDPE mentioned above. Additionally, the LDPE tubing is sized based upon the OUTSIDE DIAMETER, the flexible tube on the inside diameter, because it is intended to be used with insert (barbed) fittings.
Russ
lngliv3
11/02/2016, 06:30 PM
You can use airline from Parker hanifin or such I am a diesel tech at a freightliner dealership I got new airline from work for the plumbing for my ro/di unit and will get 3/8 or 1/2 for waterchanges and such . It's will handle it most air systems run at 135-150 psi with no leaks using push-loc fittings .
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