O P E R A T I O N A N D M A I N T E N A N C E M A N U A L
PF-50 Series Filter (ver. 4/5/05)
PAGE # 15
FILTER VESSEL
The filter vessel is constructed of carbon steel with a fusion bonded epoxy lining and polyester coating.
The vessel is designed with a handhole/manhole located in the upper head for service. The internals are
constructed of corrosion resistance sch. 80 PVC plastic. The underdrain assembly is a header lateral
configuration design to help induce even flow through the media. The underdrain laterals can be removed
individually by rotating each lateral counter clockwise until all threads are disengaged. The 3 point
overdrain assembly is designed to distribute the influent evenly over the top of the filter media. The
internal assembly should be thouroghly inspected before adding media. To inspect the internals follow the
shutdown procedure. Carefully remove the filter vessel handhole by removing the hex nut on the crab
clamp of the filter vessel (do not drop the handhole into the filter vessel.) Refer to Loading Media (page 7).
BACKWASH CYCLE
When the pressure drop across the media bed reaches its terminal differential pressure (16 psid), it is
necessary to initiate a backwash. The backwash cycle must be completed in order to keep the media from
becoming contaminated. Higher differential pressures drive the debris deep into the media bed where they
cannot be flushed out. Over a period of time, the buildup of debris will cause a media failure and
channeling or plugging of the media will occur.
Automatic Units
Controls are furnished with a factory preset pressure differential switch, manual backwash override push
button and a 24 hour time clock to activate a backwash cycle. Upon an initation of a backwash cycle the
electric valve actuator will reposition the valves into the backwash mode.The backwash cycle is preset from
the factory for three minutes. After completion of the backwash cycle the valve actuator will reposition the
valves into the filter mode. The duration of the backwash time may be adjusted if necessary. Please
consult the factory before adjusting the backwash timer. It is essential that the backwash time remain at a
minimum of three minutes to insure that the media is cleaned properly.
Manual Units
The manual units function in the same manner as the automatic units except the valves have to be manually
repositioned into and out of the backwash cycle. The filter unit will need a backwash cycle when the
differential pressure reaches 16 psid or a minimum of every 24 hours. For units supplied with pump, the
operator must shut off the pump before repositioning the valves into or out of the backwash cycle. For filter units
utilizing the system for a backwash supply, reposition the valves, and then turn pump back on. The backwash
cycle should run three minutes. After completing a backwash cycle, the pump should be turned off and the
valves repositioned to the filter cycle. Once the valves are repositioned the pump can be turned back on. For
filter units utilizing an external source for a backwash supply the pump must remain off during the three minute
backwash cycle. After three minutes, the valves are repositioned into the filter position and the pump can be
turned back on.
NOTE:
Always relieve any trapped air in the filter vessel.
NOTE:
Always relieve internal vessel pressure before attempting any repairs or adjustments on the filter unit.
