Plumbing pipe sizes?

[grantgoold]

Folks I am looking for some information on the size of your plumbing pipes. I am particularly interested in the kitchen, shower, bathroom sink, and toilet. I already have the sizes for waste/gray returns.

I have 3/8 pex tubing and 1/2 inch cooper pipe already on hand.

Sure would like to have good pressure when connected to public supply. Wife likes showers that dont require shut off during the experience.

Any help would be greatly appreciated.

Thanks

Grant

[papatony]

bring the water in in1/2 then reduce to 3/8 going to shower and faucets . run 1/2 to water heater and back to 3/8

[JohnEd]

Grant,

I would make all runs in 1/2 pex, as in a house that has 90PSI.  Use your 3/8 inch stuff for the hot water return that goes back to the fresh tank from each HW valve.  Use this, with a button valve, to circulate the hot water back to the tank and get the hot water right up to the valve so you don't waste water letting it run to get hot before showering or anything else.  You can also use this to "heat" the fresh tank in winter using the HW heater and with design and insulation that could be your wet bay freeze proofing.

HTH,

John

[bevans6]

I used 1/2" PEX for everything.  Didn't bother with the HW return trick.

Brian

[luvrbus]

Keep this mind 1/2 Pex and 3/8 copper are almost the same ID you add the crimp fitting to 3/8 Pex you are down to about a 1/4 inch our S&S job has 5/8 inch

good luck

[gumpy]

I used 1/2" pex with 1/2" copper manifolds.  I wish I would have made my shore input 3/4" so I could fill my tanks quicker, but it's really not a big issue,
and I don't think I've ever seen a shore connection inlet in 3/4" anyway.

If you're using barbs for the pex, 1/2" barbs restrict down to about 3/8". If using the push in type connectors, there's little or no restriction.

[robertglines1]

After your faucet temp selector in shower on the way to shower head there is a 1/4 to5/16   orfice going to shower head or reducer at shower head that limits flow.All that said I used 1/2 inch all way thru even thought it is reduced in end use to a much smaller  outlet.  FWIW    Bob

[luvrbus]

Unless I am way off base here and that does happen Pex 1/2 inch is 3/8 Id without the barb fittings 3/8 Pex is not going to work for you very good so go with copper you have it will be 1/2 ID and the fitting will be the same

good luck

[TomC]

Use the Pex manifold for each plumbing fixture-then you could just turn off that one if you have a problem and continue to use everything else.  Use 1/2" going to each fixture, then use 3/4 coming into the manifold. Keep the pressure down around 45psi, but use two pumps in parallel for increased volume.  Good Luck, TomC

[Melbo]

If a a water line supplies more than two appliances it should be 3/4 if you work off a manifold all the supplies can be 1/2 inch and you will get plenty of water.

HTH

Melbo

[Jriddle]

All have said what would have said. I would not put the 3/8 in. I did ours in 1/2 and find my system to be as good as my house. It works so well that when boomdocking I have to watch the water supply. I have a manifold and have the shower and bathroom sink on one hot and cold line and the kitchen sink and toilet are on the same cold water line. The kitchen sink has its own hot water line. I figured that the chances of running all them at once was pretty slim.

John

[Doug1968]

Grant,

I am just completing the water plumbing on my coach. I purchased two 1" Pex manifolds (6 port) with built in ball valves. I used one manifold for the cold water supply line and one for the hot lines. All of the lines up to the manifolds are 3/4" Pex and all of the supply lines from the ball valves to the fixtures are 1/2" Pex.

One thing I wish was different is that the ShurFlo pump has only 1/2" inlet and outlet?

I have 168 gallons of water and an 80 each black and gray tank. I am all plumbed up into the coach but I am going to look at adding the circulation back to the water tank to eliminate wasted water when waiting for the hot to show up.

I have filled the system and checked for leaks and I have run the pump and everything seems fine.

I am not sure I would use the Pex system again. A lot of money for fittings and I don't feel that the fitting availability is all that good. For those who still have plumbing to do buy the fittings on-line as they are half the cost of Home Depot.

Good luck, let us know how it turns out.

Doug

[Seayfam]

I used 1/2" PEX for everything.  Didn't bother with the HW return trick.

Brian

This is how I did mine. Plenty of water and lots of pressure, even with dishwasher and laundry going at the same time.
On the drain side of things, I used 1-1/2 drains for the kitchen sink and the bathroom lav. The shower I used 2" and the toilet I used 3" The toilet is almost directly above the tank and so is the shower.

Good Luck
Oh I almost forgot GO STEELERS

Gary

[pipopak]

Every time you go from 1/2 to 3/8 you are effectively putting a restrictor in the pipe. Also copper is not probably a good idea, you may have leaks at the unions due to vibration. VERY IMPORTANT to protect ANY kind of pipe at all/any rubbing points. My preferred method is to put a plastic sleeve on the pipe and then fill with some expanding foam as needed.

[gus]

Pip is right, avoid using any kind of rigid pipe, vibration will kill it. My 4104 is all flex tubing but my 4107 has a lot of copper tubing, a really bad idea.

Rigid can't be avoided for sewer pipes but the use of flexible connectors solves that problem.