Basic Principles - Culligan CTM 21 Installation, Operation, And Service Instructions With Parts Lists

Basic Principles

Activated Carbon Filter
Filters reduce unpleasant taste and odors from the water supply. In normal operation, the water passes through the multi-
port valve into the top of the media tank. As it flow down through the mineral bed, sediment in the water is filtered out and
objectionable dissolved gases are absorbed into the mineral. The clear water that leaves the bottom of the media tank
and goes into the service lines is free from many disagreeable taste and odors.
Depth Filter
Depth filters filter both heavy sediment and suspended matter from the water supply. In normal operation, the water
passes through the multi-port valve and into the top of the media tank. As the water flows down through the mineral bed,
sediment in the water is filtered out. The clear water that leaves the bottom of the media tank and flows through the ser-
vice lines is free from most sediment and suspended matter.
Filtering Process
To keep the filter operating properly, it is necessary to periodically remove the accumulated sediment from the mineral
bed. This done by a three-step process:
Backwash
The direction of flow through the tank is reversed, and the mineral bed is backwashed. This action expands and agitates
the bed, releasing the sediment that is then carried up and out to the drain.
Settle
The tank is allowed to be in an idle state to tallow the different types of media to stratisfy and settle. Water flow to the
drain will be present during this step.
Fast Rinse
A rapid downflow flush repacks the mineral bed and washes out traces of sediment not removed by backwash.
Backwash Frequency
Generally, backwash the CTM filter once per week. However, more frequent cleaning is recommended for water with high
turbidity. On carbon filters operated semi-automatically or automatically, backwash when the pressure drop across the
bed is 8–10 psi higher than a normal clean filter bed.
On depth filters with pressure gauges, the differential pressure across the filter can be monitored. A depth filter should be
cleaned when the differential pressure across the filter increases by 8–10 psi over the pressure differential across a clean
filter bed.
2 Cat. No. 01029343
2 Culligan® Culligan Top Mount (CTM) Water Filters