| In the diagram below, there is a sand filter with a multiport valve in the waste position. The water enters through the backwash line and is directed straight out to the sewer line. This setting is useful for draining the pool. It can be used to vacuum the pool to waste, however if a large amount of mud or grit is vacuumed through the backwash valve, the residue can damage the gasket or internals on the valve due to it’s abrasiveness. |
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