How to Guide
112
Plastics Technical Manual
Hydronic Heating, Chilled
Water or Geothermal
Applications
When plastic piping is used for recirculating systems such
as hydronic, chilled water or geothermal heat pump systems,
careful consideration of piping material characteristics and
system requirements must be made. This includes taking
into account pressure, temperature, flow velocity, design
stresses, environmental factors and the chemical resistance
of the piping materials to the fluids (heat-transfer fluids,
anti-freeze solutions and other chemicals) in the system.
Ultimately the engineer, designer or owner must evaluate
these characteristics and system requirements in order
to select the correct piping product for the particular
application. The table below highlights some of the key
points to consider when designing or installing these types
of systems.
This manual is not a complete engineering reference
addressing all aspects of design and installation of these
systems. Many excellent references are available on
this topic. The International Ground Source Heat Pump
Association: www.igshpa.okstate.edu or The GEO Exchange
at www.geoexchange.org.
“DOs” for all hydronic applications
• DoinstallCPVCSchedule80domesticwatersystemsusing
IPS P-70 or Oatey Industrial Grade primers.
• Do install CPVC Schedule 80 domestic water systems
usingIPS714orOateyCPVCHeavyDutyOrangesolvent
cements.
• InstallinaccordancewithbothCharlottePipeandFoundry’s
andsolventcementmanufacturer’srecommendationsand
installation instructions.
• Followrecommendedsafeworkpractices.
• Verifythatthemaximumoutlettemperatureandpressureof
the boiler is less than the temperature and pressure rating
of the pipe (see charts below).
• Always use the proper derating factors with FlowGuard
GoldandCorzanCPVCpipetondthepressureratingat
the applicable operating temperature.
• Always follow applicable codes and approvals when
installing plumbing and heating equipment.
• Ensurethatthesystemdesignallowsforthermalexpansion
and contraction as recommended in the Charlotte Pipe and
FoundryPlasticsTechnicalManual.
• UseonlyCPVCxbrassthreadedtransitionttingswhen
installing FlowGuard Gold systems.
• Usepropersolventcementingpractices,includingbeveling
andproperdaubersizing.
• Alignallpipingsystemcomponentsproperlywithoutstrain.
Do not bend or pull pipe into position after being solvent
welded.
• ProvideadditionalsupporttothebrasssideofaCPVCx
brass transition or other metallic components to support
the weight of the metal system.
• Usecheck valves, heat traps or back ow preventers to
prevent cross-connections between hot and cold water lines.
• Flush the interior of heat exchangers or the exterior of
condenser coils thoroughly with mild ionic detergent solution
to remove incompatible oils prior to piping installation.
• Rinse with clean water to purge the system as a nal
flushing.
• Verifythatallboilercleaningandsealingchemicalsused
in the hydronic radiant heating system are compatible with
CPVC.
“DON’Ts” for all hydronic applications
• Do not exceed the operating temperature or operating
pressure of the piping system.
• DonotuseCPVCmaleorfemaleadapterswithplastic
molded threads for FlowGuard Gold systems.
• DonotusetheCPVCpipingsystemtosupportanymetallic
components.
• Do not use compression ttings for hydronic radiant
heating applications.
• Donotusesolventcementthatexceedsitsshelflife,has
become discolored or has gelled.
• DonotuseCPVCteesorotherCPVCcomponentsashot
SPECIAL CONSIDERATIONS
Prior to installing PVC or CPVC piping in hydronic
applications, it is important to flush the interior of the heat
exchangers and the exterior of the condenser coils
thoroughly with a mild ionic detergent solution to remove
incompatible oils. Failing to do so could result in system
failure and property damage.
Verify that all boiler cleaning and sealing chemicals used in
hydronic radiant heating systems are compatible with PVC
or CPVC. Failure to do so could result in system failure and
property damage.
Equipment leaks in refrigeration or HVAC systems may
release POE oils or other contaminants into the piping
system. These oils and contaminants are incompatible with
PVC or CPVC and such exposure may result in pipe or
fitting failure regardless of flushing.