CONNECTIONS
–
PLUMBING
32
EXPANSION CONTROL VALVE
Local regulations may make it mandatory to install an expansion control valve (ECV) in the cold water line to
the water heater. In other areas, an ECV is required if the saturation index is greater than +0.4 (refer to
“Water Supplies”
on page 13).
The expansion control valve must always be installed after the non return valve and be the last valve
installed prior to the water heater
(refer to diagrams on page
30
)
. A copper drain line must be fitted to the
expansion control valve (refer to
"Relief Valve Drain"
on page 32).
The expansion control valve and it‟s easing gear must be accessible from ground or floor level. A position of
up to 1800 mm above ground or floor level is recommended. It must not be installed either on the roof or in
the ceiling space, unless it is an accessible trafficable area. Extend the cold water line from the expansion
control valve to the cold water inlet fitting on the Sunstat valve.
The valve 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
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 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 water heater 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 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 to
“Multiple Installations”
on pages 36 and 37).
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.
INSTALLATION CHECK LIST
Once the installation is completed and the system is full of water, it is IMPORTANT to check the following:
Right hand side of the collector array is 20 – 35 mm (one solar collector) or 40 – 70 mm (two solar
collectors) higher than the left. If in doubt use a spirit level.
The solar hot and solar cold pipes grade downwards from the storage tank to the solar collector(s). If in
doubt use a spirit level.
