Filter Diagnostic

Why does my filter run at a high filter pressure and has reduced water flow to the pool?

A dirty filter maybe the problem. When the filter pressure rises 8-10 PSI over the clean starting pressure, it is time to backwash or clean the filter. If there is algae in the pool, it maybe clogging the filter, keeping the pressure high. The filter cannot kill algae. Contact Excel Pool Service for proper chemical applications. If the filter pressure continues to run high with reduced water flow to the pool, the pump may be moving more water than the filter is designed to handle. Check the flow ratings of both the pump and filter to ensure they are sized correctly.

You may have a blocked or plugged return line. Contact Excel Pool Service.

Why is the filter continuing to run at high pressure even after backwashing?

Make sure you are following the instructions in your Hayward owner’s manual. The sand bed may be clogged with mineral deposits or other material that will not backwash away. Some calcium based chlorines and other alternative sanitizers could cause a build-up in your sand bed. You may need to change the sand.

Before you change the sand in you filter, try removing approximately 1” of the top layer of sand, and replace with the exact amount of sand removed. This sometimes rids the sand bed of the deposits clogging the filter.

You may have to clean you filter system with a special filter cleaner, contact Excel Pool Service for proper procedures.
Check to see if there is a closed or partially closed valve on the return piping.

Your pump may be too small to provide sufficient flow for proper back-washing. Your filter will filter properly, but if your pump does not supply at least 60% of the filter’s designed flow rate, you filter will never backwash completely. Refer to the label on you filter for flow rate requirements. It may be necessary to upgrade the pump or downgrade the filter.

Your pump may also be exceeding the maximum allowed flow rate of you filter causing excessive back-pressure. Check you Hayward filter owners guide or the operations label on you filter for the maximum allowed flow rate. You may have to downsize the impeller or pump to a lower horsepower or change the filter for one that will accommodate the pump’s flow rate. If allowed to continue, a pump that exceeds the recommended flow rate of a sand filter could cause the sand bed to channel (small channels in the sand that allow debris to pass unfiltered). This would cause debris to by-pass the filter.