Low pressure fresh water system?

[Feral Cement]

My Tartan 34C had old, gross clear vinyl plumbing to hand pumps for the fresh water system. I tore it all out and bought new clear vinyl tubing - thick wall (at least compared to the Lowes version). I was going to install a Johnson 35 psi pump but was told that the tubing would not handle that much pressure. Any thoughts? Any recommendations for a pump with an adjustable pressure switch? Or maybe an in-line pressure reducer that does not cost more than new, stronger tubing?

Johnson Pump 1.1 Pump/Faucet Combo 12v

Thanks!

John

[colemj]

Is the tubing you bought completely clear or does it have a web of threads going through it? If the latter, this is just fine with your pump. If the former, it should be replaced with the latter.

Better yet, make most of the runs out of pvc or PEX and just use short pieces of hose when necessary to make connections. PVC is dirt cheap and PEX is pretty inexpensive. Our entire boat is plumbed with PEX (or a similar product), and it has a large, complex water system.

Mark

[Feral Cement]

Originally Posted by colemj

Is the tubing you bought completely clear or does it have a web of threads going through it?

Completely clear, no reinforcing web. What psi will get water delivery but not splash-back pressure at the head sink?

John

[colemj]

I don't know, but that really isn't the right tubing for your application. And you will be disappointed in how much organic growth it will get.

On the other hand, it seems like it should be able to handle 35psi if it really is thick walled.

Mark

[sailorchic34]

The clear vinyl tubing has a rated working pressure of about 40-45 psig. For a 35 psig pump it should be just ok. Its not rated for hot water, only cold.

A long time ago standard design was to have 8 psig at the fixture. However with the water saver faucets and showers that has gone up to 15-20 psig minimum. Some newer shower heads need 30-40 psig.

Of course one could simply remove the restriction orifice disc under the faucet aerator and drill out the shower head orifice.

[RainDog]

FWIW my RV has adjustable pressure. The water system should be similar to your boat. 20 PSI is not nearly enough for the shower. It is fine for the faucets. I keep it at 45 PSI normally. I would not go with less than the 35 if you will be running a shower head.

[Suijin]

You should bite the bullet and buy the reinforced tubing that is specifically engineered for your purpose. Having leaks on your boat is a recipe for irritation, and is dangerous in some cases too. It's not something you want to have to redo in a few years. You can probably unload the tubing you bought on Craig's list if the store won't take it back.

Most of the modern pumps provide variable pressure, as needed, with the more powerful pumps allowing for the use of multiple fixtures at the same time. It's not going to keep the system pressurized to it's full capacity when it's idle, afaik.

[SV THIRD DAY]

So there we were on our first trip down the outside of Baja heading to Mexico. Our Pearson 365 had 3-50Gallon water tanks. On day 5 with 6 left to go, our Home Depot water line got soft from the heat of passing through the engine room and ruptured. Before we knew what happened, 100 gallons of water was pumped into the bilge by our house fresh water pump and then overboard by the bilge pump. We didn't have a water maker back then and with a crew of 6 I learned my less in trying to save a few bucks on things that matter. Water lines are something that Matter!

[Dennis.G]

They don't even use the clear tubing (non-reinforced) in RVs, so that should say something.

[kthoennes]

The previous owner used some of that non-reinforced clear tubing on our boat. It doesn't burst necessarily but it does expand and gets loose and floppy and leaky around the connections. Just hanging on by the hose clamps and not snug. It also kinks too easily. Buy the proper reinforced line, it's not worth your time and future hassle to use the clear stuff.

(i still don't trust pex - feels like connecting soda straws to each other.)

[Jman]

PEX is the answer. Works and approved for hot and cold in household installations (75+ PSI). No hose clamps! (although on our re-plumbed boat we needed 2, water tank had a 1/2" male nipple, so we just used 2 clamps on a short piece of reinforced hose to a PEX to barb fitting).

You can find almost any possible PEX to anything connection to attach to existing fixtures. Almost all plastic fitting available inexpensively online, search PEX RV fitting to avoid boat prices.

Easy disconnect/reconnect!

Only downside is flexibility, but in some cases makes life easier because you can just push it through existing holes.

PEX itself could not be cheaper, about $0.25 a foot at big box home stores.

[jkindredpdx]

Last summer I heard hissing down below galley sink. The old yellowed clear tubing ruptured and spewed, fortunately I was on-board (although I turn off the pressure system when I'm away). It only took a couple days with numerous beer breaks to replace all the old tubing in the boat with reinforced from the "walking distance" chandlery which only cost pennies a foot more than clear. That said, I use clear tubing for my beer keg and I've taken it up to 40lbs for a short while when carbonating my homebrew.

[Feral Cement]

Thanks for your comments, everyone! With no existing on-board shower plumbed in, I'm gonna use the 35 psi pump and my existing (already installed) clear vinyl tubing with a 20 psi pressure reducer just past the pump. Unless y'all think 15 psi would be enough for rinsing dishes and brushing teeth?

John

[sailorchic34]

It should be fine that way. If pressure is too low at the faucet, remove the nozzle (it unscrews) and remove the plastic piece with the tiny hole in it. Most have the orifice disc pressed in to the diffuser. A one minute job.

If you have a accumulator / expansion tank, locate the pressure reducing valve after the tank.

[SV Maclas]

I vote for the pex tubing too, or at least reinforced tubing!