Whenever the media filter outlet turbidity increases by more than
0.5 NTU over the lowest reading since the last backwash.
Whenever the "media filter plugged" yellow light and horn go on.
As specified in the shutdown procedures.
c. Clean the strainer basket whenever strainer plugged warning light
and horn come on.
d. Replace the cartridge filter whenever the cartridge filter plugged
warning light and horn come on or the pressure drop exceeds 20 psi.
e. Membrane cleaning at operating intervals as determined from the high
pressure pump hourmeter (25 hours when using polyelectrolyte, 100 hours on
fresh water, 200 hours on sea water); as a part of long term secured
shutdown procedures; and following citric acid cleaning.
f. Mechanical breakdown and normal shutdown.
23. The performance of the RO elements will have to be checked regularly.
Have the operator use the portable TDS meter to measure the TDS at the four
RO vessel sample valves and at the combined sample as follows:
a. Compare the combined TDS with Table 1-7.
If the amount is greater,
proceed to troubleshoot the problem.
RO Vessel Maximum TDS Difference