I’m trying to find out if the use of CPVC water piping is acceptable with a 1978 hot water boiler system where the thermostat on the boiler goes up to 240 degrees and the pipe is rated to 180 degrees. I realize that this type of pipe is used in the in-floor heating systems of new construction, but this is used in the open ceiling of the basement and is connected to the vertical pipes via copper couplings. Thanks for any insight or areas I can research to determine the acceptability of this use.
CPVC pipe is rated to 210F. After that it loses its shape. I have yet to hear of a successfully installed poured radiant system with CPVC pipe inside the pour. The labor to secure, glue fittings, and repair leaks make installation more difficult than other materials. CPVC may be used by some installers as manifolds and exposed pipe when temperatures are lowered to 160F. The usual plastic used for radiant is PEX today.
Likewise some systems use Pex as it can take 240F, although few hot water heating systems are used higher than 180F.