Plumbing Size?

[steveirving]

Hi,

Getting ready to pull out the old leaky/patched copper plumbing in our '59 Tradewind. I plan on installing PEX.

Any tips on what size to use? Should use 1/2" or 3/8" or a mixture of different sizes?

[n2916s]

Granted, my trailer is newer than yours (86) but I can tell you that most of the main runs are 1/2". With the pressure regulator on mine set at 40psi, that gives me pretty good flow rates. The leads that branch off the main to the bathroom sink are 3/8" though.

I used PEX and Sharkbite fittings for the few repairs I've had to make and all has held up fine.

Mike

[Protagonist]

Originally Posted by steveirving

Hi,

Getting ready to pull out the old leaky/patched copper plumbing in our '59 Tradewind. I plan on installing PEX.

Any tips on what size to use? Should use 1/2" or 3/8" or a mixture of different sizes?

Simple answer, you want the nominal diameter of the PEX to be the same as the nominal diameter of the copper you're replacing. Inside diameters will be slightly different for the same nominal diameter, but that doesn't matter for this application.

[HiHoAgRV]

1/2" PEX is widely available, 3/8 can be a bit more scarce - thus my choice to go with 1/2" all the way.

[TG Twinkie]

I used 1/2" throughout. That way all of the fittings are the same size. Also used the flexible braided stainless lines to connect to all fixtures, including the water heater. I posted some pics on my blog.

[utee94]

Yup, I used 1/2" throughout because it was the most common and available size.


-Marcus

[donh1]

Most 1/2" Pex is 3/8 inside diameter. I would stay with 1/2" myself.

[Wazbro]

Like others have said 1/2", bigger is better.

The only place it is good to restrict water flow is at the point of use, such as where it comes out of the shower head, not where or before it goes into the shower head, that way you still have pressure.

[Jammer]

Originally Posted by steveirving

Hi,

Getting ready to pull out the old leaky/patched copper plumbing in our '59 Tradewind. I plan on installing PEX.

Any tips on what size to use? Should use 1/2" or 3/8" or a mixture of different sizes?

3/8" is completely sufficient, in terms of flow rate, for any runs that serve a single fixture. Smaller pipe means less water wasted running the tap until the water gets hot or cold, as the case may be. And although there isn't much difference in the weight of the pipe, using 3/8" will reduce the weight of water and fittings by a couple of pounds.

Most people, including the mother ship, just use 1/2" because then you only need one crimp head and one size of fittings and pipe.

[BAB]

...also, you can buy red for hot and blue for cold. I started using PEX about 7 years ago when I added plumbing in my house...used it throughout my pool house and for other projects. Sharkbites work....but I dropped the coin and bought a crimp tool (around $100)...it came with multiple heads so I can use it with all sizes of PEX. You can also find fittings that'll let you connect it to copper and even PB pipe. Once you use it you will never go back to anything else. GREAT for DIYers and most builders are now using it in new home construction. Side benefit: it has a bit of give if there's a freeze...unlike copper.

[steveirving]

Any thoughts on crimps vs clamp pex?

[donh1]

Cannot tell you what to do, but will say i have replumbed three houses using the crimp method.HAVE HAD ZERO LEAKS, THIS HAS BEEN OVER A FIVE YEAR SPAN. I am not a trained plumber. I would spend the money to buy a good crimper tool. (I bought mine at Lowes big box store.

[Kevin245]

Originally Posted by donh1

I would spend the money to buy a good crimper tool. (I bought mine at Lowes big box store.

Ditto here. I will say that crimping requires some forethought as the tool size can limit access when working in tight spaces.

Kevin