Instruction manual

9
Electrode Installation
All electrodes for the Webmaster series are provided with signal conditioning electronics, and
conductivity sensors may be located up to 250 feet (75 meters) from the controller, and pH/ORP
sensors may be located up to 1000 feet (303 meters) from the controller . It is highly recommended
that the electrodes be installed within 10 feet of the controller in order to make periodic electrode
calibration more convenient.
Electrodes should be located such that they respond rapidly to a well-mixed sample of the cooling
tower water and the treatment chemicals. If they are too close to the chemical injection point, they
will see spikes in concentration and cycle on and off too frequently. If they are too far away from
the chemical injection point, they will respond too slowly to the concentration changes, and you
will overshoot the set point.
If the electrode cables need to be extended, then 24 AWG shielded twisted pair cable should be
used. Always route electrode cables (or any other low voltage wiring) in conduit that is separated
from any AC voltage wiring by at least 6 inches.
The optional pH and ORP electrodes must be installed such that the measuring surfaces will
always remain wet. The U trap provided in the manifold design should achieve this, even if the
recirculation pump stops, as long as the sample valve remains closed. These electrodes also must
be installed with the measuring surfaces pointing down; that is 5 degrees above the horizontal, at a
minimum.
If the electrodes are to be submersed in the cooling tower sump, mount them firmly to the sump,
and protect the cable with PVC pipe to prevent premature failure. Place the electrodes in an area of
good solution movement.
3.4 Icon Definitions
Symbol Publication Description
IEC 417, No.5019 Protective Conductor Terminal
IEC 417, No. 5007 On (Supply)
IEC 417, No. 5008 Off (Supply)
ISO 3864, No. B.3.6 Caution, risk of electric shock
Pending
Caution, High temperature, risk of
burn
ISO 3864, No. B.3.1 Caution