5/8 Pex Tubing And Fitting Options

[Indydyne]

I have a leak in my supply lines to the bedroom register. I am having a difficult time finding push to connect unions and 5/8 Pex tubing.  I don’t have good access to use a compression fitting to make the repairs, hence the desire for ptc fittings. I have researched 3/4 airline and DOT push to connect fittings and found they are good to 150 psi and 200 degrees F. The OD of the airline is the same as 5/8 ID Pex.   Has anyone tried this before?  Does anyone have a good source for 5/8 Pex and Pex ptc fittings?

[TW Racing]

You should be able to find a sharkbite for 1/2 pex that is 5/8 OD at Lowe’s or Home Depot. I purchased my own pex crimp tool so I can now make repairs as needed.

[Ivan K]

I think Brian is talking about 5/8 ID pex?

I thought I have one like it from HD but I was wrong, seems I have 3/4 ID.

Edited February 1 by Ivan K

[Indydyne]

Correct.  The lines are 5/8 ID Pex B.  The OD of the line is 3/4. 

[Ivan K]

Since the 5/8 ID isn't a standard size anymore, maybe this would work? And they sell by the foot.

[Indydyne]

Ivan, 

 

Thanks for the tip. Unfortunately the OD of Pex al is too large. It also takes special fittings. 

[TW Racing]

Here in Las Vegas I would have to go to a plumbing supplier for that since it’s not a normal size. Have you had any luck at your local plumbing shops?

I forgot to ask, what type of fittings are you looking for, angle stop …etc

[Indydyne]

I checked all our local suppliers. They can get 5/8 Pex tubing, but I would need to buy 500 feet. They cannot get the ptc unions. 

[wamcneil]

It’s just feeding the bathroom?  Surely no need for tubing as large as 5/8.  Maybe cut it back to some place where you have good access for crimping and replace the entire run with 1/2”? 5/8-1/2 crimp reducers should be available. 
Have you considered cinch clamps instead of crimp rings? Cinch might work in tight spots easier than crimp. 

Edited February 2 by wamcneil

[Indydyne]

This is the run to the bedroom register in the rear closet. Cinch clamps might work, I am just trying not to invest in tools that I hopefully won’t need again in the future…

[wamcneil]

Cinch tool is just about $25!

[David Pratt]

Ace, Lowe's and Home Depot sells the Pex 3/8", 1/2", 5/8" and 3/4" In rolls and 8 -10 foot sections.

[Steve Merritt]

There is a 5/8 pex and fittings designed specifically for hydronic heating systems and boilers that is for use in radiant heat systems like concrete floors and driveways and is also used in systems with registers. It has its own fittings and is normally a dark brilliant red in color. I am an electrician by trade and talked to a plumber and a HVAC contractor I know and both know it exists but have never bought or installed it.

[Ivan K]

The problem here is that PEX lines are identified by OD but Brian is looking for 5/8 ID which is nonstandard size.

[jacwjames]

If he lives near a larger city I'd suggest finding a supply house that sells this type of item.  When I needed fittings for my air system I went to a local company called Royal Brass, they carry a wide variety of this type of item.  If they don't have it they'll be able to source. 

The pex tubing the coach can't be something so obsolete you can't find fittings for it.

[dandick66]

3/4 inch heater hose (automotive) will slip over the 5/8 PEX.  You can use hose clamps to secure it.  I’m sure it can take the heat of the Aquahot.  

[wamcneil]

Oh, I finally clued-in on the term “register” in the original post. So we’re talking about a coolant line from the aqua hot. Sorry, I thought OP was talking about a WATER line.  

Edited February 3 by wamcneil

[Steve Merritt]

I went down and double checked my system just to be sure and my coach has black or red 5/8 automotive heater hose with really thick walls and double braided cording in the walls sort of like 4 wire hydraulic hose. There is no pex in my system anywhere that I can find.

Edited February 3 by Steve Merritt

[Ivan K]

39 minutes ago, dandick66 said:

3/4 inch heater hose (automotive) will slip over the 5/8 PEX.  You can use hose clamps to secure it.  I’m sure it can take the heat of the Aquahot.  

Good point, that is how our registers actually connect to pex lines, whatever their size.

[Indydyne]

All,  

Thank you for all the good ideas. I learned a lot about DOT and pex pipe/fitting specifications with this adventure, so at least that was fun. Long story short, my lines are 1/2 pex, not 5/8 as previously thought.  I did not have calipers with me to measure when I found my leak.  I was sighting the size off the 3/8 lines that run to the washing machine.  Rookie…. 
 

After a not so relaxing evening with a fish tape, I am all fixed up with new 1/2 pex supply and return lines.  My lines also connect to the registers with heater hose as Ivan’s do.  Thanks again!

[DBRV.0]

On 2/4/2024 at 8:30 AM, Indydyne said:

my lines are 1/2 PEX , not 5/8 as previously thought.  I did not have calipers with me to measure when I found my leak.  I was sighting the size off the 3/8 lines that run to the washing machine.

Very understandable!  Recently, I was in the belly of my beast and was looking at the PEX lines for the water supply.  Visually, I thought I could see 3/8 and 1/2, but when I fetched my digital calipers, I found everything to be the same.  Very deceiving.  And they are all 1/2" PEX B, and even my flexible nylon-reinforced water hose reel supply line is 1/2.  If you think you have 3/8 somewhere and need to be sure, I encourage you to measure again, for a washing machine should want a flow greater than something minor such as a sink, and even my sinks use 1/2.

Edited February 6 by DBRV.0