Rheem XWELL XC-10 Owner's Manual And Installation Instructions page 18

CONNECTIONS – PLUMBING
The pipe sizing for hot water supply systems should be carried out by persons
competent to do so, choosing the most suitable pipe size for each individual
application. Reference to the technical specifications of the water heater and local
regulatory authority requirements must be made.
Cold Water Valves: An isolation valve (shut off valve) must be installed on the cold
water line to the water heater. A pressure limiting valve is recommended to be
installed if the mains supply pressure exceeds 640 kPa. Local regulations may
require a non-return valve to be installed. Refer to the schematic diagrams on
page 19.
Pipe Insulation: It is recommended to insulate the hot water pipe work to reduce
heat loss and also prevent any contact with the hot pipe. It may be necessary to
insulate the cold water line to and the hot water line from the water heater in
accordance with local regulatory authority requirements.
Pressure Relief Valve Drain: A drain line must be fitted to the pressure relief valve
to carry the discharge clear of the water heater. The pressure relief valve outlet has
a 7 mm barb connection. Connect the drain line securely to the valve using a pipe
clamp. Cable ties must not be used.
The drain line must have a minimum internal diameter of 7 mm and be capable of
maintaining its internal area under all operating conditions. Water discharged from
the outlet of the drain line can be of a high temperature and under certain conditions,
boiling or steaming.
The drain line from the valve to the point of discharge must be as short as possible,
have a continuous fall all the way from the water heater to the discharge outlet, be
supported over any length that is not vertical, be left open to atmosphere and have
no tap, valves or other restrictions in the pipe work. The outlet of a drain line must be
in such a position that flow out of the pipe can be easily seen, but arranged so
discharge will not cause injury, damage or nuisance.
The termination point of a drain line must comply with the requirements of national
and local plumbing standards and regulatory authorities. A termination point of
between 150 mm and 300 mm above a floor trap is recommended.
Warning: As the function of the pressure relief valve on this water heater is to
discharge high temperature water under certain conditions, it is recommended pipe
work downstream of the pressure relief valve be capable of carrying boiling water.
Failure to observe this precaution may result in damage to pipe work and property.
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