Rheem Solar Hiline 52D180 Owner's Manual And Installation Instructions page 44

CONNECTIONS – PLUMBING
RELIEF VALVE DRAIN
DN15 copper drain lines must be fitted to the temperature pressure relief valve and expansion control valve (if
one is installed) to carry the discharge clear of the water heater. Connect the drain lines to the valves using
disconnection unions. The drain line from the valve to the point of discharge should be as short as possible,
have a continuous fall all the way from the water heater to the discharge outlet and have no tap, valves or
other restrictions in the pipe work.
A drain line from a relief valve must comply with the requirements of AS/NZS 3500.4. A drain line must be no
longer than nine (9) metres with no more than three bends greater than 45° before discharging at an outlet or
air break. The maximum length of nine (9) metres for a drain line is reduced by one (1) metre for each additional
bend required of greater than 45°, up to a maximum of three additional bends. Where the distance to the point
of final discharge exceeds this length, the drain line can discharge into a tundish.
Subject to local regulatory authority approval, the drain lines from the temperature pressure relief valve and
expansion control valve from an individual water heater may be interconnected.
The outlet of a drain line must not discharge onto roofing materials, roof gutters or onto paved areas. 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 AS/NZS 3500.4.
In locations where water pipes are prone to freezing, drain lines must be insulated, must not exceed 300 mm
in length and are to discharge into a tundish through an air gap of between 75 mm and 150 mm.
If a drain line discharges into a tundish, the drain line from the tundish must be not less than DN20. The drain
line from a tundish must meet the same requirements as for a drain line from a relief valve.
Where a drain line crosses over a metal roof, the pipe work must be fully insulated with weatherproof lagging
to offer corrosion protection to the metal roof against water runoff over the copper pipe. The insulation must
be UV resistant if exposed.
For multiple installations the drain lines from several water heaters can discharge into a common tundish (refer
"Multiple Installations"
to on pages 47).
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.
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