| | | Skimmer Water is removed from the pool via an overflow (skimmer) which has a flap that positions itself according to the surface of the water. The skimmer increases the flow velocity of the surface water and draws any debris on the water surface into the skimmer. The debris accumulates in a filter basket. The basket must be emptied regularly, about once a week. If your pool has a main drain, the flow must be regulated so that about 30% of the water is taken from the bottom and about 70% from the skimmer. Pump The pump creates the vacuum (suction) at the skimmer and then forces the water through the cleaning filter, through the heater and back to the pool via the inlet jets. The filter basket in the prefilter of the pump must be emptied regularly, for example when backwashing. Before starting the pump, make sure that it is full of water, otherwise the shaft seal of the pump may be damaged. If the pump is above the surface of the pool water, the water drains back to the pool when the pump is stopped. Then, when the pump is started, it may take some time for the pump to evacuate all the air in the vacuum line and start pumping water. You can overcome this by closing the valve before the pump and then immediately switching off the pump. Doing this retains the water in the vacuum line. Filter The pool water is cleaned mechanically by a sand filter which design filters out particles down to about 20 u (microns, thousandths of a millimetre). On top of the filter tank there is a valve which controls the flow of water through the filter. The filter is two-thirds filled with filter sand with a grain size of 0.6-0.8 mm. As more and more dirt is trapped in the filter, the back-pressure increases. It can be read off on the backwash valve pressure gauge. When the back-pressure has increased by about 0.2 bar since the filter was last backwashed, the filter must be backwashed again. This means reversing the flow through the filter so that the dirt is released from the sand and flushed out via the drain. The filter sand should be changed after 6-8 years. Inlet jets The cleaned and heated water is returned to the pool via the inlet jets. The jets should be aimed slightly upwards to move debris towards the skimmer. | | |