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CONNECTIONS – PLUMBING
37
PIPE SIZES
To achieve true mains pressure operation, the cold water line to the water
heater should be the same size or bigger than the hot water line from the water
heater.
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.
RELIEF VALVE
The temperature pressure relief valve is shipped behind the lower front cover of
the water heater. The temperature pressure relief valve must be fitted before
the water heater is operated. Before fitting the relief valve, make sure the probe
has not been bent. Seal the thread with Teflon tape - never hemp. Make sure
the tape does not hang over the end of the thread.
Screw the valve into the correct opening
(refer to the installation diagram on
page 30
) leaving the valve outlet pointing downwards. Do not use a wrench on
the valve body - use the spanner flats provided.
RELIEF VALVE DRAIN
Temperature Pressure Relief Valve
A copper drain line must be fitted to the relief valve to carry the discharge clear
of the water heater. Connect the drain line to the relief valve using a
disconnection union. The pipe work from the relief valve to the drain should be
as short as possible and fall all the way from the water heater with no
restrictions. It should have no more than three right angle bends in it. Use
DN15 pipe.
The outlet of the drain line must be in such a position that flow out of the pipe
can be easily seen (refer to AS/NZS 3500.4) - but arranged so hot water
discharge will not cause injury, damage or nuisance. The drain line must
discharge at an outlet or air break not more than 9 metres from the relief valve.
In locations where water pipes are prone to freezing, the drain line must be
insulated and not exceed 300 mm in length. In this instance, the drain line is to
discharge into a tundish through an air gap of between 75 mm and 150 mm.
Warning: As the function of the temperature pressure relief valve on this
water heater is to discharge high temperature water under certain conditions, it
is strongly recommended the pipe work downstream of the relief valve be
capable of carrying water exceeding 93°C. Failure to observe this precaution
may result in damage to pipe work and property.