SAF
– 4500
910101-000341 / 07.2019
Page 9 of 26
DESCRIPTION OF FILTER OPERATION
Filtering process:
The SAF-4500 is a sophisticated yet easy-to-operate automatic filter, with a self-cleaning mechanism driven by an electric
motor. The SAF-4500 is designed to work with various types of screens in filtration degrees from 10 to 500 micron, and is
available in 4", 6" and 8" inlet/outlet diameter.
The water enters through the inlet pipe into the coarse screen from outside in, and through the fine screen from inside out. The
"filtration cake" accumulates on the fine screen surface and creates head loss to develop.
The coarse screen is designed to protect the cleaning mechanism from large dirt particles. Usually, it does not accumulate large
quantities of suspended solids and is not cleaned automatically.
Self-cleaning process:
The SAF-4500 initiates the self-cleaning process when either the pressure differential across the screen reaches a pre-set value
or the flush timer reaches its preset timed interval.
The fine screen filter element is cleaned by the suction scanner, which rotates in a spiral movement while removing the
filtration cake from the screen, and expels it out through the exhaust valve.
A 2-way (fwd/rev) drive unit that is attached to the scanner by a threaded shaft rotates the scanner and provides the linear
movement.
The exhaust valve is activated for the duration of the cleaning cycle by a 3-way solenoid. During the 20 seconds self-cleaning
process, filtered water continues to flow downstream.
System Operation modes:
The filtration system may be found in one of the following modes:
1. Filtering mode: This is the normal operating status. The flush mode is idle and the power light on the control board is lit.
2. Flush mode: The motor and exhaust valve activate according to the previously described self-cleaning process.
3. Continuous flushing mode: It is possible to activate the self-cleaning mechanism continuously by setting the SW1 switch in
the control board to "CONT." position.
4. Malfunction mode: If the filter malfunctions, the self-cleaning operation stops, the malfunction light on the control board is
turned on and a 24V AC external output is activated.
The filtration system enters a malfunction mode under any of the following conditions:
1st.
A continuous signal from the pressure differential switch longer than the PD fault time-out (default value=15 minutes)
indicates that the filter is unable to clean itself.
2nd.
The motor Over Load protector was activated, either manually or due to actual over load.
3rd.
Limit Switch malfunction - (usually, simultaneous activation of both limit switches).
