Rheem 610340 Owner's Manual And Installation Instructions page 21

CONNECTIONS – PLUMBING
EXPANSION CONTROL VALVE
Local regulations may make it mandatory to install an expansion control valve (ECV) in the cold water line to
the storage tank. In other areas, an ECV is required if the saturation index is greater than +0.4 (refer to
"Water Supplies"
on page 9).
The expansion control valve must always be installed after the non-return valve and be the last valve installed
prior to the storage tank (refer to diagram on page 20). A copper drain line must be fitted to the expansion
control valve (refer to "Relief Valve Drain" on page 21).
The valve, if installed within 500 mm of the water heater, must be insulated with closed cell polymer insulation
or similar (minimum thickness 9 mm) and the insulation installed so as not to impede the operation of the
valve. The insulation must be weatherproof and UV resistant if exposed.
RELIEF VALVE DRAIN
DN20 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 storage tank. 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 storage tank 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 9 metres with no more than three bends greater than 45° before
discharging at an outlet or air break. The maximum length of 9 metres for a drain line is reduced by 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 storage tank may be interconnected.
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. Drain lines must not discharge into a safe tray.
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 DN25. The drain
line from a tundish must meet the same requirements as for a drain line from a relief valve.
For multiple installations the drain lines from several storage tanks can discharge into a common tundish
"Multiple Installations"
(refer to on pages 24 and 25).
Warning: As the function of the temperature pressure relief valve on this storage tank 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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