6.8
Thermal insulation
Thermal insulation requirements for hot and cold water
services are specified in the National Construction Code
NCC and in AS/ NZS 3500.
In cold water applications, the likelihood of pipe damage
due to freezing can be reduced. It is, however, not possible
to prevent static water from freezing completely. For longer
periods during which freezing is likely to occur, pump warm
water periodically through the pipe system. Alternatively,
the complete system should be drained.
6.9
Noise reduction
Eects of water hammer:
The low elastic modulus of PE-Xa pipes and their ability to
expand quickly and contract slowly enables the pipes to
absorb water hammer eectively.
In cold water service installations, the water hammer eect
can be reduced by up to 75% compared to metal pipe
installations.
6.10
Water heater connection
EDGE
TM
silver and EDGE
TM
red system can be used for
recirculating hot water systems provided the operating
temperature, pressure and level of disinfectants does not
exceed the capabilities of the piping system. Refer to
Chapter 9.
REHAU recommends the installation of both isolation
valve and non-return valve connected directly to the inlet
of every water heater or with metallic piping between the
valves and the water heater. REHAU recommends that the
non-return valve be connected closest to the water heater
and with the isolation valve at the up-stream of the non-
return valve
6.10.1 Storage water heaters
All storage water heaters should be fitted with operational
temperature and pressure relief valves for safety in the
event of malfunction of the heater’s operation. The rating
of the temperature and pressure relief valve must be
determined by the storage water heater manufacturer in
terms of maximum temperature and pressure as required
for the design and operational requirements of the water
heater.
If the storage water heater does not have provision on the
heater for fitting such a valve, REHAU recommends the
installation of a temperature and pressure relief valve on
the tee-connection of the heater’s hot water outlet and its
outlet piped to a drain location. This will allow the release
of hot water during the heater’s normal operation and in
the event of safety operation of the valve. REHAU also
recommends that the valve be operated manually every
six months.
Outlets of storage water heaters must be fitted
with a minimum of 1 meter of metallic piping prior
to the installation of EDGE
TM
silver or EDGE
TM
red system.
6.10.2 Instantaneous water heater
Before connecting EDGE
TM
piping system to either electric
or gas-fueled instantaneous water heaters, the installer
must check the appliance manufacturer’s instructions
regarding the connection of polymer pipes. The appliance
operational temperature and pressure may exceed the
capabilities of EDGE
TM
piping and might cause failure of
the piping system. Some manufacturers of instantaneous
water heaters state that connection of their appliances
to polymer piping systems is not suitable or subject to
restrictions.
The installer must confirm with the appliance
manufacturer that the maximum operational limits
of the appliance will not exceed those of the piping
system. REHAU recommends that only appliances with
temperature control devices which can, at all times, restrict
the outlet water temperature to within EDGE
TM
piping
system’s capabilities, be installed in conjunction with
EDGE
TM
piping system.
6.10.3 Water heaters with uncontrolled energy
sources
EDGE
TM
silver and EDGE
TM
red pipes should not be used
with uncontrolled energy sources and installation of a
tempering valve is required.
6.10.4 Solar water heaters
As per AS/NZS 3500 requirement, polymer pipe systems
must never be used on the flow and return piping to any
solar panel.
Solar collectors and other uncontrolled heat
sources generally have operating conditions which
exceed those of EDGE
TM
pipe system.
• Never use EDGE
TM
pipes in the flow and
return piping to any solar collectors/panels.
• Do not install EDGE
TM
pipes in the flow and
return of any uncontrolled heat source
(e.g. wood fire heaters, etc.).
• If a heat storage tank is used, EDGE
TM
pipes can be used after the tempering valve.
Potential back siphoning of super heated water
through the cold port of the tempering
valve from cold feed to the uncontrolled
heat source (including solar panels) must be
prevented through adequate measures, e.g.
fitting a suitable high temperature rated non-
return valve between the cold feed to the solar
panels and the tempering valve.
To Next Page
Loading...
Need help?
General