Scale; Hard Scale - EcoWater CHC Series Service And Troubleshooting Manual

5.10 Scale-

Scale formation within a system can occur for many reasons. This section outlines the items to do and
check to aid in CHC's determination of possible causes for scale formation .
There are three major types of scale that can form within a treated system. They include Hard Scale
(like glass), Soft Scale (reformed granular or sandy sludge), Silica Scale. Some other forms of scale
have also been discussed.

5.10.1 Hard Scale

Hard Scale is an indication that either the CHC treatment is not working as well as it should, or
that the cycles of concentration are too high. Thing to verify are as follows:
1. CHC function:
a. Is the pressure on the CHC unit appropriate (78-85 psi for a CHC 20, 88-105 for all
other CHC units.). Some causes for pressure loss may include suction side vacuum
leak, plugged strainers, incorrect valve positioning, plugged suction manifold or line,
loss of system power, defective pump, plugged CHC nozzle channels or loss of
pump prime due to air entrapment in pump or piping. Verify the cause and take
appropriate action. All gauges must be verified by turning the system off and the
pressure should decline back to 0, and then back on to measure the pressure.
b. The vacuum must be at least -25 inHg.(may vary depending upon elevation of the
site). Loss of vacuum may be associated with a leaky gauge, tube, connection and or
fitting, low pump pressure, plugged nozzle and or too much back pressure on the
chamber.
c. Back Pressure too high or too low. Back pressure must only be 2-5 psi. if it is too
low or too high make sure to adjust.
d. Alignment of Nozzles. As the water enters the end bells it should not enter one of
the nozzle's channels directly. It should however, pass directly to the blank area
between two channels. This verification requires a visual inspection of the nozzles.
e. Inappropriate Venting of discharge. If the discharge of the CHC discharge drops
and is not vented, a siphon can occur causing an abnormal backpressure on the
cavitation cloud, it is important that the gasses are released to the atmosphere, and
that the back pressure is controlled within acceptable limits.
f. Inappropriate distribution of treated water. When one CHC unit is treating multiple
towers or sumps and you have a scaling problem on one of the towers, this is a
possible indication that the treated water is not being dispersed to all towers equally.
You will also want to verify that the suction from the tower is equal to the others as
well.
g. The CHC nozzles may be blocked. Open the chamber and make sure the nozzle
ports are open and free from any large debris.
h. The CHC is undersized. This can occur when the initial quotation information was
gathered. It is possible that if the system water volume was underestimated, the
quoted CHC treatment required can be undersized and will require an upgrade. This
can also be the result of a significant change in Make-Up water hardness or Silica
levels.
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