I just finished replumbing my attic with PEX. As suggested in other
posts I ran all the lines first before disconnecting the existing steel
pipe. Here in Houston, everything is in the attic, so it makes getting
the job done in the winter almost a requirement. One thing I installed
that I don't see any reference to, was a water manifold. I ordered one
from Vanguard Maniblock from www.houseneeds.com. They carry a complete
line of PEX supplies.
It is basically a circuit braker for the water system (don't forget the
special wrench to make the manifold connections). The cold supply line
enters, another cold goes out to the Hot Wtr Htr, then returns hot.
There is a hot and cold side of the manifold. The volume of the
manifold helps keep constant water pressure to each fixture. You then
run dedicated lines for each house fixture from the manifold. Any cold
or hot line can be turned off independently on the manifold.
It makes testing your finished work easy too.
When I connected the new system, I could then turn on each fixture,
using my trusty CSI flashlight checking all my connections for leaks.
I only found one, in a shower gooseneck.
All the PEX conncections were dry and tight. I set two inline brass
ball valves in the 3/4 PEX.
One on the supply side to isolate the manifold from the main line and
one on the cold in line on the hot water heater. this way I can
isolate the heater to replace it without turning off the water to the
rest of the house.
I found a nice 1/2 and 3/4 crimper and cutter on Ebay for around $80.
I did not replace all my steel verticals, in some cases I attached a
collar and short extension to raise the pipe above rafter height to be
able to get the PEX crimpers on at 90 degrees to the pipe. This is a
MUST. I did run PEX down the walls to both baths where I could cut the
drywall inside closets to replace fixtures and backing boards. PEX
requires good backing boards and special brass fittings that the PEX
attaches to by way of the standard nipple, then gives a threaded recess
for a spigot pipe or shower gooseneck.
My method of installation gives me the option of later running PEX down
the walls and installing directly to the sinks, toilets etc. and
avoids the necessity or tearing up brickwork to replace hose bibs and
other nearly inaccessible fixtures. I didn't find any corroded
vertical pipes, only the horizontals lying on the rafters. I cannot
begin to tell you how many pinhole were on the pipe, both 1/2 and 3/4.
An important point to remember when using PEX is the water requirements
of your appliances. I found the washers and even your dish washer
fillers may work on a timer based on a average flow rate, and not the
actual water level. So if your pressure is low, or you undersize your
PEX (I would not go below 1/2" no matter what you read or are told)
your washers may be running at well below the water capacity you think
they are. Low water levels are hard on your washer and your clothes
for that matter.
Unfortunately, a lot of the old Texas Gulf coast homes vintage 70's and
80's(and probably newer) was built by illegals learning on the job,
employed by unscrupulous developers. My attic piping was a joke. No
fixtures had backing boards, the plumbing was held firm by well placed
gobs of mortar. The brick work of my chimney in the attic was actually
propped in place by toe-nailed 2x4's ostensibly placed to keep the
brick and wet mortar in place while it set.
A good reciprocating saw, with coarse metal cutting blades is a must.
It enabled me to remove pipe that would have been nearly impossible to
get out otherwise.