Backwash Options
18
United Industries, Inc.
P.O. Box 58
Sterling, KS 67579
800-835-3272 • 620-278-3160
Fax 800-500-3115 • 620-278-3115
www.towerflo.com
Form TFH-BW-OPS:10/02:
Data presented here is the best available at the
time of publicaton. United Industries and/or its
representatives assume no liability for its use.
Series
TFH
TOWER-FLO
®
Filters are equipped to automatically back wash using water from the same source they are filtering. In the
vast majority of sidestream applications this is perfectly satisfactory. However, in some cases it is not desirable to dispose
of system water for filter backwashing. In those cases, TOWER-FLO offers two alternative approaches as described below.
FRESH WATER BACKWASH FROM MUNICIPAL SUPPLY
This option uses municipal water supply for backwashing. When the filter’s differential pressure switch activates backwash,
the system pump is stopped for the duration of the backwash operation and a valve is opened to allow city water to back-
wash the vessel. The flow rate and pressure of the city water supply must be controlled so as not to exceed the limits of
the vessel; conversely, the flow rate must meet the vessel’s minimum backwash flow requirement of 75% of flow rate.
Ordering this option changes the facepiping from the standard configuration (as shown on pages 9, 10 & 23) to the
configuration shown on the following page. Municipal water supply is connected to the bottom valve as shown.
Additionally, this option provides a flow control valve, factory preset to the maximum flow rate of the vessel, to be
installed on site in the municipal water supply line to the filter.
The end-user is responsible for the addition of a
pressure-controlling device in the fresh water supply line set to a maximum 30 psi.
Local code may also
require the addition of a back flow preventer in the fresh water supply line.
FRESH WATER BACKWASH FROM STATIC SUPPLY, PUMP ASSISTED
This option uses some totally independent, static pressure water supply (such as an accumulation vessel) for back-
washing and relies on the system pump to create the backwash flow. This option is useful when it is not desirable to
backwash with system water and municipal supply is either not available or cannot meet the minimum flow requirement.
Ordering this option provides an additional three-way valve mounted to the suction port on the pump pre-strainer.
The three-way valve is normally open on the suction line from source and closed to the backwash water source. It
switches position simultaneously with the two backwash control valves.
