Multiport Functions
 Multiports direct the water through the filtering system. There
are multiport valves on almost all sand filters and on most vertical
grid DE filters. A malfunctioning multiport valve allows water to go
in the wrong direction, for example water would go out the backwash
line when it is placed in "filter" position. It would also allow DE
powder to go back into the pool when it shouldn't. It is important
to know how your multiport valve should function.
Multiport Positions
FILTER
Normal operating position.
Water goes from pool, through filter, and back to pool. |
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BACKWASH
Used to clean debris from the filter.
Water goes from the pool, through the filter, and out the backwash
line.
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RINSE
Used to rinse tank after backwashing.
Water reverses cycle through the filter to rinse fine residue from
inside the tank so it doesn't end up back in the pool. Rinsing helps
to eliminate blow back into the pool after backwashing. See "backwashing"
for more tips.
WASTE
Used to bypass the tank.
Water goes from the pool to straight out the backwash line. This way
heavy algae & debris does not go into the filter or through sand
filters & back into the pool when vacuuming. With a DE filter, you
can drain the water level in the pool after heavy rains without
losing any DE powder.
RECIRCULATE
Used as a service aid.
Water goes from the pool, through the multiport, and back to the
pool, bypassing the filter. This position can be used to
troubleshoot when circulation is poor. Put the system on recirculate
and see if the circulation stays the same or improves. If it
improves, the problem is in the filter because you've just
eliminated it. It may need backwashing or to be hosed out. If the
problem persists, there may a problem with the pump or in the
suction line.
CLOSED
This position closes the multiport (not used very often). DO NOT
make the mistake of putting the multiport on "closed" and turning
the filter on...not a good mistake!
Place multiport between any two positions when winterizing.
To vacuum as if on "waste" with a filter that does not have a
multiport valve, simply vacuum with the bottom drain valve partially
open. See Service Tips or
Vacuuming.
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