Plumbing Re-Do

[silverloaf]

I'm in the process of replacing the water lines in our '88 30-P. I have installed a new water pump and on-demand hot water heater. I'll likely change out some of the fixtures as well. The old gray stuff is 30 years old so I'm switching to the modern PEX.

I have several different ways of installing various fittings in the line. The 1st one is the crimp-type method used in residential application. A steel ring is squeezed over the tubing and barbed fitting using a crimping tool. Its a relatively inexpensive method but does involve a special tool ($25 and up). It is very robust but not meant for periodic removal.

The 2nd method involves CTS fittings consisting of either a shark-bite fitting or a compression type fitting. Both can be removed, although the compression is by far the easiest. But none of these fittings are cheap($5-$12 each).

So it's a tradeoff between cheap fittings requiring a special tool versus expensive parts and no tool.

I'm thinking about doing most of the fittings with the crimp method. I would install some compression fittings in key places should I need to easily separate a line for drainage, repair, etc.

Any thoughts from the troops if there is a better mousetrap than I've described? Have I overlooked any "what ifs"?

Thanks in advance!

[KYAvion]

I haven't installed PEX tubing in my Avion yet, but I have in several parts of my house. I went with the copper crimp rings that require the special tool. Keep in mind this is different from the stainless cinch clamps that also require a special tool.

When I get around to redoing the lines in my trailer, I'll do everything using the the copper crimp rings and brass PEX fittings. In areas like you mentioned where easy dismantling is a desire, I'd just use the same standard brass PEX fittings (pex fittings, not barbed fittings) with food grade vinyl braided tubing and a hose clamp on one side. While I haven't installed any PEX tubing in my Avion yet, I have installed lots of brass PEX fittings in my trailer. I've got several PEX connections (pex tees, pex shut offs, etc) and vinyl braided tubing fastened with hose clamps from where I modified all the existing grey polybutylene lines so they slope downhill for gravity draining (makes winterizing a breeze for frequent weekend trips in cold temps). In areas where I had trouble with the polybutylene fittings, I cut the fitting out and replaced the fitting and section with a PEX fitting and clear braided vinyl tubing. In areas like this I inserted the grey polybutylene inside the vinyl tubing and fastened via a hose clamp. I've use the trailer extensively year round on city water with no issues whatsoever, so it may be awhile before I feel the need to swap all the polybutylene lines out for PEX.

[silverloaf]

Thanks for the info.

I've elected to use the stainless steel crimp ring. I can get everything I need at a local plumbing supply co. I deal with. However, I ordered a crimping tool on-line.
https://www.amazon.com/IWISS-Ratcheting ... l_huc_item

By the way, the plumbing supply co. has a PEX fitting that converts the grey polybutylene tubing to PEX.

[silverloaf]

Below are a few pics of the new water and gas rough-in plumbing in our trailer. Not shown is the water supply to the sinks and tub.

The loops in the fresh water hoses are designed to minimize flow vibration from the water pump.

I fabricated the copper manifolds to jump over the parallel connection points on the tankless water heater.

I also used bend supports in the corners rather than 90 degree elbows.

So far, no leaks.

CD8B6CD6-2C64-4EAB-AFBB-A4D9C5AAEE0B.jpeg (46.35 KiB) Viewed 15409 times

44C136C9-2EE7-491B-BEA3-9EFA5FB508BA.jpeg (41.54 KiB) Viewed 15409 times

6897AC8B-FEA5-401B-B84B-E4DF9317961C.jpeg (43.16 KiB) Viewed 15409 times

[KYAvion]

Looks great Silverloaf. Good idea using those bend supports with the PEX instead of 90's. Fewer connections that way. Which water heater did you decide to go with, and what's the metal box to left of it?

I like the plywood panel you made to seal the opening to the freshwater tank area. I've thought about doing the same since cool air coming through that space is noticeable in really cold temps (near zero degree temps). However, one concern I've had is leaving that area accessible in case I ever need to access any of the fittings, so for the time being I've just stuffed fiberglass in there.

[Razorback]

I like that...... very neat and tidy....and functional!

[KYAvion]

To the left is that metal box I was curious about.

IMG_2817.JPG (51.16 KiB) Viewed 15386 times

[silverloaf]

The cover surrounding the hoses and gas line is actually two pieces. It splits at the center line of the hoses and line. Both halves can be removed without disconnecting them.

When I replaced the belly pan, I cut out a corresponding rectangular access hole to get to the water fittings at the bottom of the fresh water tank. I fabricated a cover plate to go over the hole.

The large square box is the Atwood tankless water heater. To the left of the tank is the transformer. It converts 110v "shore" power to 12v.

I checked out the water heater function as part of a systems check of water and gas lines. It works, however, I have yet to put it through its paces.

[Erehtuo]

Hey silverloaf, Did you have to drop the belly pan to change all that plumbing out? Everything looks topside so I'm thinking no but not sure if the connection to the tank was accessible from anywhere but the bottom. Trying to plan ahead if this is feasible with cabintry and woodwork removed or if the pan would need dropped as well.

[silverloaf]

It's not necessary to remove the belly pan to replace water lines. Even the supply (suction) hose from the tank to the pump might could be replaced though the access cover near the pump.

Bear in mind that residential PEX is not as compliant as one might think. I actually did portions of the new plumbing twice because clearance condidions in an Avion are very tight. I tried using bend supports in the corners. But the supports did not produce a true 90 degree bend. I ended up using more crimp fittings than I wanted to. Each fitting theoretically reduces system flow; to what extent I do not know.


Attached are some pictures of the fresh water tank fittings and plumbing to the bathroom. Ignore the black wire sticking into a tank fitting; strictly to keep the wire out of harm's way during re-assembly.