Publicité
Les langues disponibles
Les langues disponibles
To Calculate Backwash Frequency - Normal Applications
Backwash frequency for households with average water use can be determined using the following guides. The guide cannot
be used if the filtered water supplies a swimming pool, geothermal pump, outside spigots or other high water demand devices
or activities. If your application includes any of the foregoing refer to the paragraph on "Special Applications" below.
People
in
Family
2
4
6
1
1
1
1
2
1
1
1
3
1
1
1
4
1
1
2
5
1
1
2
6
1
2
2
Example: You have four in the family and 8 ppm of iron. Refer to the guide and locate the box intersected by four in the family
and 8 ppm of iron. The figure supplied is 2. This means your filter control should be programmed to backwash twice in twelve
days - that is every sixth day. If the figure had been 3 it would mean 3 backwashes in twelve days or every fourth day.
To Calculate Backwash Frequency - Special Applications
To ensure adequate reserve capacity and prevent loss of water pressure between backwashes the figure of 15,000 (not the
full 30,000 ppm capacity) is used to calculate backwash frequency. Determine your backwash frequency as follows:
1. Estimate daily iron removal requirements using the following calculation:
No. of people in family
x 75 gallons of water per person
+ No. of gallons of water for special use
= No. of gallons of water required per day
x Iron concentration (ppm)
= Daily iron removal requirements (ppm)
2. Establish backwash frequency using daily iron removal to complete the following calculation:
15,000 iron removal capacity (ppm)
÷ Daily iron removal requirements (ppm)
= No. of backwashes required in 12 day schedule
Example: You have four in the family, 8 ppm of iron and a swimming pool requiring 46 gallons of water per day.
4
People in the family
x 75
Gallons of water per person
300
Gallons of water for family
+ 46
Gallons of water for the pool
346
Gallons of water required per day
x 8
Iron concentration
2,768
Daily iron removal requirements (ppm)
15,000
Iron removal capacity (ppm)
÷2,768
Daily iron removal requirements (ppm)
5.4
Backwash frequency (days)
The calculation indicates the need to backwash every 5.4 days. The control can only be programmed to backwash at intervals
of two, three, four, six and twelve days. The control would be programmed to the closest more frequent setting i.e. every four
days.
Section 5: Backwashing Instructions
Iron Content (ppm)
8
10
12
14
1
1
1
1
1
1
2
2
2
2
2
3
2
2
3
3
2
3
3
4
3
3
4
6
1. Locate the box intersected by the number of
people in your family and the parts per million
16
18
20
(ppm) of iron in your water (if your ppm is between
1
1
1
two numbers on the guide, use the higher
2
2
2
3
3
3
number.)
4
4
4
2. The number in the box represents how many
4
6
6
times your filter has to backwash in a twelve day
6
6
6
schedule.
9
Publicité
