Originally Posted by GordMay
Do NOT use Quest "polybutylene" pipe. !!!
Not quite true - and for the rest of the story - There is nothing wrong with the Qest system** as I have installed and used it for over 20 years in both RV's and boats.
- - The ** is important as you should not use it unless you KNOW what you are doing. Polybutyl pipe is very good for installations where flexibility is needed and freezing is a problem. The pipe will not burst when frozen and thawed. The problem with the Qest/Polybutyl is you cannot glue it. For mass installation where time is a cost factor the system was originally sold using "crimp" fasteners which weakened and corroded over the years and resulted in significant water leaks
. So the system was withdrawn from the home/housing market. The failures were all attributed to improper installation. Those who have had so-called "professionals" work on their boats know all about improperly done installations of this or that.
- - Compression
fitting have always **if properly installed** been secure and mine have lasted now for almost 20 years. If exposed to excessive heat over time (e.g. up close and personal to a water heater) the oils that keep the polybutyl soft and flexible evaporates and the fitting will fail.
- - The Qest brand is just about gone from the home repair (e.g. Home Depot) market but remains strong in the RV market. You would be hard pressed to find the material these days.
- - In the marine
market other manufacturers, Sea-Tech and Whale are marketing
a white translucent with similar push on/compression type fittings - they are much more elegantly engineered for D-I-Y use - and of course, with a higher price
- - As with a lot of products in the professional markets, how the system is installed and maintained makes a world of difference. The same bottom paint
system will work great if applied expertly or will fail to do its job if it is slapped on by somebody who does not know how to do it correctly.
- - In boats you have very few choices these days for potable water supply. Pipe/hose are the options with most after-market going for white vinyl hose. I have not been to a boat show
in about 4 years but friends with new upscale boats are using the white marine Sea-Tech/Whale systems version pipe. Copper is problematical as it is difficult to install after the boat is complete and is subject to corrosion
. Normal PVC and CPVC pipe is really too brittle for the high vibration, flexing and slamming that boats are subject to in the oceans.
- - You really need to know what you are doing with just about any system except vinyl hose and the new Whale/Sea-Tech high priced pipe. Although boats appear to be very similar to "house" installations - they really are not. They are probably more akin to aircraft installations. Vibration, high shock loads, support/restraint for inverting of the vessel and the highly corrosive environment
of the oceans make the installation design and techniques more critical. And more expensive.