Section 11: Screen Maintenance; Screen Damage - Pentair PR AQUA ROTOFILTER Installation And Operation Manual

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SECTION 11: SCREEN MAINTENANCE

11.1 Screen Damage

The screens on the Rotofilter are made from
polyester fabric molded into polypropylene grid
frames. Although strong and resilient, they may
become damaged from the following:
11.1.1 Punctures
Prevention
Protecting the Rotofilter from large debris is the
best way to prevent puncture damage.
Remedy or Repair
If the grid is still intact around the cell that was
punctured, use the square rubber plugs supplied
in the owner's kit to repair the screen. See Section
11.3 for plug installation.
If damage is more extensive, replace the entire
screen. See Section 11.5 for screen removal
and installation.
11.1.2 Breakdown by Ultraviolet Light
Prevention
Do not allow direct UV light to hit the screens. If
the Rotofilter is installed outside, a weatherproof
shelter should be built to prevent UV light from
reaching the unit.
Ultraviolet (RFUV) units come with UV light block
baffles to prevent UV breakdown of screen panels.
The baffles stop direct UV from penetrating the
screen membrane.
You will still see light emitting from
NOTE
UV chamber inside of the drum
area. This is normal.
11.1.3 Mineral Deposits
Remedy or Repair
Certain high water-soluble mineral environments
may cause screens to be obscured by mineral
deposits. The frames and polyester screens are
unaffected by acids effective in cleaning away
these deposits. Either of the following solutions is
effective:
1. Remove all affected screens as outlined in
Section 11.4, and fully immerse in a 5 to 15%
muriatic acid solution until clean.
PR Aqua Rotofilter Drum Filter Installation and Operation Manual
™
2. Follow the appropriate Shutdown procedure,
as outlined in Section 8.3.
3. Drain the tank/sump. Prepare an appropriate
quantity of the following phosphoric/citric
acid solution:
• 3 liters (3.17 quarts) of clean water
• 1 liter (1.05 quarts) phosphoric acid (84%)
• 110 grams (0.25 pounds) commercial-grade
citric acid
• 30 cc (1 fluid ounce) liquid detergent (common
dishwashing fluid is acceptable)
4. With the backwash system off and tank/sump
empty, run the drum motor and evenly apply the
acid solution to the screens using a common
garden sprayer or similar device.
5. Leave the drum motor turning for 20 minutes
to prevent pooling and drip-off. Rinse the
screens and the inside of the machine with
a pressure washer.
Do not exceed 7.0 kg/cm2 (100 psi). Pressure above
7.0 kg/cm2 (100 psi) will damage the screens. Do not
hold the pressure head closer than 46 centimeters
(18 inches) from the screens. Do not use an
oscillating pressure head. An oscillating pressure
head will damage the screens.
6. Flush and drain or pump out the enclosure
(tank/sump).
7. Follow the Rotofilter Startup procedure as
outlined in Section 8.1. 11.1.4 Biological Growth
Prevention
No single solution resolves this problem due to
the high diversity of growth that can occur. We
recommend that screens be kept away from light
and heat sources to minimize biological growth.
Remedy or Repair
1. Remove growth with a high-pressure power
washer as described in Section 11.2. For
stubborn deposits, a 15 to 20% sodium
hypochlorite solution can be effective when
applied as follows:
2. Follow the appropriate Shutdown procedure as
described in Section 8.3.
3. Drain the enclosure (tank/sump).