On Nov 7, 1:52 pm, Oren wrote:
On 7 Nov 2007 18:47:59 GMT, Clark wrote:





ransley wrote in
oups.com:

On Nov 7, 12:21 pm, Oren wrote:
On Wed, 7 Nov 2007 10:25:48 -0500, "BETA-32"

wrote:
Can PEX piping be used for a cast iron hot water radiator heating
system?
And the site did say 140f for saftey, for a reason, plastic has
failed. 140f would not get me through a winter without being cold.
Boilers can run at 190-200f safely, aquastats go bad. Plastic pipe is
is just not safe at high temps for the long term. Also his system
pressure must be figured in.

Perhaps you aren't reading the correct portion of the website. The
Wisbro/Uphonor and Zurn pex's are rated at 200 degrees and 80 psi.

Pex is approved by code for hydronic radiator systems in many areas.

I Vanex PEX - 160 psi @ 73°F and 100 psi @ 180°F.

From the data sheet:*

* Vanex tubing can also be used in "continuously-recirculating"
plumbing systems at temperatures of up to 140° F while still
maintaining excellent chlorine resistance. For information on the
suitability for other hot and cold water applications not listed here,
consult with your Vanguard Piping Systems representative.- Hide quoted text -

- Show quoted text -

Clark, I see it as rated for 200f, but the site also says " for saftey
and conservation 140F". He can of course do it but it does fail, its
plastic. Radiant underfloor heating is around 110f and lower pressure
than a 185f boiler. My car is rated 5000 rpm redline, , but for long
life it never goes there. Metal is proven, Pex does not have a long
track record in years. nobody really knows how Pex will last at high
temps and pressure over 50 years++.