HEALTH AND SANITATION
c.
33
Float switch installation
o The float switch shall be tethered to a rigid freestanding
object, such as a vertical section of pipe or the pump, that:
• permits the float switch to rise and fall without any
obstructions; and
• is located in an area where it is easily accessible
and can be withdrawn from the tank without
requiring entry into the tank.
o To set the operating parameters of the float switch:
• to maximise rainwater collection, the tether length
should be as short as possible: 75mm [3 in.]. Refer to
the manufacturer’s installation instructions for details;
• to maximise rainwater collection, the tether point
should be as low as possible (so that the float is
50mm [2 in.] above the pump intake when in the
down position); and
• if using a dual float switch configuration, the float
switch controlling the solenoid valve should be
located a minimum of 75mm [3 in.] above the float
switch controlling the pump.
d. Other water level sensors shall be selected and installed
in accordance with applicable National/Provincial/ Local
codes and regulations, and all electrical connections must
be made by a licensed electrician in accordance with the
manufacturer’s instructions.
Solenoid valves and shut-off valves
a. Select the type and size of solenoid valve and/or shut-off valve.
• All valves must be suitable for potable water and pressure
applications.
• Valve openings must be the same size as the piping where the
valves are located.
• Top-up systems typically use an N/C solenoid valve.
• Solenoid valves with a ‘slow close’ or ‘soft close’ are
recommended.
b. Electrical requirements
• Solenoid valves must be wired into a power supply in
conjunction with a water level sensor.
c.
•
•
Solenoid valve and shut-off valve installation
Solenoid valves and shut-off valves used as part of a top-up
system shall be installed on the potable water supply pipe
upstream of the air gap.
Solenoid valves must be installed by a licensed plumber and
electrician in accordance with the manufacturer’s instructions.
d. Water hammer protection
• If a ‘slow close’ or ‘soft close’ solenoid valve is not used,
a water hammer arrester shall be installed on the potable
water supply piping upstream of the solenoid valve, in
accordance with applicable national/provincial/ local codes
and regulations.
June 2019 Volume 25 I Number 4