7
Sizing Requirements
Water Pressure
The water system must have a pump large enough to deliver the recommended backwash
rate with a minimum pressure at the inlet of the filter of 30 psi. If the existing system cannot
do this, it must be upgraded to do so. Whenever possible, the water system should be ad-
justed to deliver at least 30 psi for even more satisfactory results.
Backwash Flow Rates
The most important criteria in sizing a filter is the capacity of the pump/supply flow and pres-
sure. The water must pass through the filter media at the proper service flow rate. The filter
must also be backwashed at a flow rate sufficient to dislodge and remove the captured parti-
cles. Failure to provide sufficient water will cause a build-up of particles in the filter media,
impairing its ability. In order for the filter to backwash and rinse properly, the pump/supply
flow and pressure must be capable of providing the backwash flow rates indicated on page
6.
Checking Available Flow Rate
There are several ways to check the available flow rate of the water supply. The following
method is intended to be simple for any application. A bucket of known volume (5 gallon
buckets are typically used) and a stop watch is required.
1.
Go to a point of use that will allow full flow when opened. This can be a garden spigot
or a fully ported valve or faucet.
2.
Open the point of use and allow the water to run in the bucket. If the water source is
supplied by a well pump allow the water to run until the pump starts then convey into
the bucket.
3.
Use the stop watch to monitor how long it takes to fill the 5 gallon bucket. Use the fol-
lowing equation to find the flow rate available;
60 Seconds / Bucket fill time (seconds) * Bucket Volume = Flow rate (GPM)
Installation, Operation and Maintenance Manual
Models: 089-IF-150, 089-IF-250, 089-IF-400,
089-IF-500