
16
PR Aqua Rotolter™ Drum Filter Installation and Operation Manual
SECTION 5: PRE-INSTALLATION
Problems that may occur if water levels are not
controlled include:
Damage to the Rotolter screens, drum shaft,
support wheels, and drum frame, due to excessive
weight caused by a high differential between water
levels inside and outside of the drum. The warranty
will be voided if the difference is greater than 30.5
centimeters (12 inches).
Reduced drum shaft bearing life, due to frequent
or constant submergence from a high outlet
water level.
Tray sludge may reenter the lter or may bypass the
lter and enter the outlet water, due to water owing
into the backwash tray of the lter from a high inlet
water level.
The above problems will result in reduced
operating range of the lter, which may cause
more frequent or continuous backwash, and will
reduce lter performance.
Continuous monitoring of the inlet and outlet
water levels (e.g., using a level transducer)
is recommended, but may not be suitable or
necessary in all applications.
• Inlet water levels should be continuously
monitored regardless of application if large
variations in ow are anticipated or could occur.
• Outlet water levels should be monitored if the
Rotolter does not have a low/high water level
alarm switch or automatic backwash system.
An outlet (level control) weir is necessary to
maintain a minimum water level inside the unit
to prevent damage. Rotolter Molded (RFM) and
Ultraviolet (RFUV) models contain integrated level
control weirs that help maintain the minimum water
level required inside of the drum. Frame (RFF)
models utilize one of two level control methods:
a weir integrated into the lter sump design, or a
level control basin installed on the underside of the
Rotolter.
A high overow weir is necessary to protect the
drum in the event of a backwash system failure.
The overow weir allows unltered water to bypass
the drum screens at critical levels and ow directly
into the outlet. Rotolters contain integrated
overow weirs. If overow directly into the outlet
is unacceptable, RFM and RFUV units will require
additional plumbing upstream of the lter. RFF units
will require an overow channel integrated into the
sump.
5.6 Backwash System Considerations
The backwash system requires a water supply, an
electrical supply, a xed pump location, and proper
plumbing.
5.6.1 Water Supply
The water supply may come directly from the
Rotolter or may need to come from an external
source. This depends predominantly on the water
quality requirements of the Rotolter application.
Some applications require highly ltered or puried
water. If water quality is not an issue, a source may
be selected based on the desired frequency of
maintenance.
The backwash system can be plumbed directly into
the ltered water supply of the Rotolter. Water
coming directly from the unit has been ltered, but
is not puried and contains dissolved nutrients that
will support bacterial growth.
This growth, combined with accumulations of ne
particles and deposition of dissolved minerals,
can cause the backwash system to foul over
time. Increased fouling will require more frequent
maintenance.
More stringent water quality requirements will
necessitate plumbing to an external water source.
Municipal water supplies generally do not contain
higher concentrations of dissolved nutrients and
ne particles, reducing the degree of fouling over
time.
Check with the local water supplier for quality
parameters. Pressure and ow rates from external
water sources should meet the values required for
the Rotolter, as specied by Pentair.