PEX Manifolds

[KYAvion]

I’ve been wanting to run PEX for awhile and decided to finally go ahead and do it along with some manifolds. The manifolds are really overkill, but after installing them in my house I thought I’d go ahead and make some for the trailer too. With the exception of the toilet, everything runs down hill to the manifolds. One valve drains the water heater and the hot water lines, and another valve drains all the cold water lines. I used 3/4” PEX for the manifolds and the cold supply and water heater supply and output. The drains are also 3/4” so everything drains pretty fast. The individual runs to the shower, bath sink, and kitchen are all 1/2”. It’s a little crowded, but all the individual runs have shut offs as well.

Since there’s no way for the toilet valve to gravity drain, I ran a tee off the cold line that feeds the kitchen sink. The tee is real close to the water pump, and I put a shut off right after the tee, followed by another tee that feeds the toilet and connects to the water pump output. This way I can isolate the toilet and pump just a small amount of antifreeze through the toilet valve.

[Razorback]

That's very nice work. I like seeing a well-laid-out plan.

[silverloaf]

I’ve been wanting to run PEX for awhile and decided to finally go ahead and do it along with some manifolds. The manifolds are really overkill, but after installing them in my house I thought I’d go ahead and make some for the trailer too. With the exception of the toilet, everything runs down hill to the manifolds. One valve drains the water heater and the hot water lines, and another valve drains all the cold water lines. I used 3/4” PEX for the manifolds and the cold supply and water heater supply and output. The drains are also 3/4” so everything drains pretty fast. The individual runs to the shower, bath sink, and kitchen are all 1/2”. It’s a little crowded, but all the individual runs have shut offs as well.

Since there’s no way for the toilet valve to gravity drain, I ran a tee off the cold line that feeds the kitchen sink. The tee is real close to the water pump, and I put a shut off right after the tee, followed by another tee that feeds the toilet and connects to the water pump output. This way I can isolate the toilet and pump just a small amount of antifreeze through the toilet valve.

I'm envious of the space you have to run the Pex. Our 30P with the rear bath and spare tire compartment was a beast to run the plumbing. I had no room for any manifolding or formed corner bends. I did create some copper jumper pieces around the tank-less water heater. I used a ton of brass connectors and elbows design with crimp-style features.

I have yet to put the system under pressure. I'm not optimistic about having good flow. All piping is in 1/2".

I do like your way better. Nice work, my friend!

[Bobbyz]

I just went for simple with the PEX. With the exeption of adding valves at the faucets, toilet and water heater. (highly recommend that) Also eliminated the fresh water pump since I have no plans to camp without hookups anytime soon. Just ran it pretty much like the original gray plastic garbage.
To winterize a cheap drill power pump where the water house hooks up and isolating the hot water heater with the valves should keep the antifreeze at a gallon or two. Used it all last winter though, so I didn't get to try it.

[Salty]

@KYAvion Nice work. You are far more ambitious than I

[KYAvion]

Given our frequency of short weekend trips in the winter, gravity draining makes it a breeze. The manifolds are really not necessary, but I got the idea after doing our house that way so I thought I might as well. I was surprised to see that my water pump didn’t take any more time to prime...at least not a noticeable amount.

BTW, Silverloaf - I bet you’ll be fine as far as the 1/2” pex and flow. Test it out and let us know!

[silverloaf]

I plan on doing that next week and let you know.

We plan on using it at the property while our house is being built. I'm hoping to have water, propane, and sewage (septic) hook-ups in place. We can then use the trailer for additional bedroom space if necessary.

[Salty]

Bob, I've got 1/2"PEX in mine, flow is just fine!

[andyykuo]

Newbie questions as our piping is different in our 1988 34x:

1) Re-piping starting point should be going forward from water entry near pump or backward from each outlet
2) Optimal manifold location for 34x - Is there another place to put manifold accessible from outside. Your manifold is under twin bed hot water tank but mine is super cramped under closet space...
3) Center bath pipe access and crossover point - I see that a panel was removed for rear bath. Where would that be for center bath? Also do I need to open belly skin to get repipe the crossover point?

[KYAvion]

Just to clarify, my 30R is a center bath with bedroom in the back. As far as running the pipe, I think the most important thing is having an organized plan ahead of time for the layout of the plumbing, and then just fishing the pex in whatever way works. Also, keep in mind manifolds are really overkill. I just did it because I felt like it, and once on a trip we did have a leak at a fitting in the bathroom and it would have been nice to have the capability to shut off just that area. Now I can if something like that happens again.

So as far as my 30R…

I fished my pex front to back. So from the bathroom and kitchen to the manifolds at the rear. I used shark bite style connections (everything is from PEX Universe) after the manifolds strictly because it’s a tight area and they made the installation easier. I made the manifolds with PEX coming off the shut offs ahead off time, and then installed the manifolds in the trailer. I installed each sharbite after that along with the pex that I fished from each fixture to the rear.

Yes, there isn’t much space where the manifolds are. If we had storage bays under the trailer, then that would have been the ideal spot. In my case, that area next the water heater made the most sense for me. I staggered the shut off valves to make each one easier to get a hand on, but keep in mind that I only operate three valves (unless something were to go wrong). I’ll close the main valve from the city water inlet if using my water tank instead of city water. Otherwise, it stays open all the time. So keep in mind I only open two valves and the entire system (except for the toilet) gravity drains. That is, all hot and cold fixtures and the water heater.

The panel you may be seeing is either the access panel for the shower connections, or the panel covering the tub wall. There was no need to remove the bellypan. Everything was accessible via inside the bathroom cabinet, via the tub panel, etc.

Also, I installed plastic pex mounting brackets along the way to ensure the pex runs downhill toward to the manifolds. This was important since I want everything to gravity drain so don’t have to mess with pumping any antifreeze through the water heater, bath fixtures, or kitchen fixtures.

As I mentioned in a prior post, I do isolate the toilet with separate valves and pump a small bit of antifreeze through the toilet valve via my water pump.