Table 31. Troubleshooting general filter issues
| Probable causes | Preventive measures | Checking preventive measures | Corrective action | |
|---|---|---|---|---|
| What to check | Signs that action is needed | |||
| Observation: Rapid increase in head loss and short filter runs Possible hazards: Reduced efficacy of pre-treatment |
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| Incoming water too dirty | Monitor effectiveness of pre-treatment | Water pressure Water flow | Increase in head loss | Install or improve pre-treatment. Consider putting a coarse cartridge filter upstream. |
| Observation: One filter blocking much earlier than the others Possible hazards: Reduced efficacy of pre-treatment |
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| Excessive flows to an individual filter | Monitor effectiveness of pre-treatment | Colour Water flow | One filter needs replacing sooner than others | The flow split may need better control. |
| Observation: Spikes in filtered water turbidity during a filter run Possible hazards: Reduced efficacy of pre-treatment |
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| Sudden changes in flow rate to a filter or filters are causing them to unload, particularly where high pressures are allowed to build-up | Monitor effectiveness of pre-treatment | Colour Turbidity | Filter unloading, i.e. releasing organic matter | Look for causes of sudden changes in the flow to the filters. |
| Observation: Flow declining and possible increase in treated water turbidity Possible hazards: Reduced efficacy of pre-treatment |
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| Changing cartridges too late | Change cartridges more regularly | Flow Pressure | Pressure is high | Is the pressure differential being checked regularly enough? |
| Observation: High filtered water turbidity Possible hazards: Reduced efficacy of pre-treatment |
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| Cartridge pores too large | Smaller cartridge pores | Colour Turbidity | Turbidity and colour are high after filter | Investigate reducing the cartridge pore size or changing from a nominal size to an absolute size. |
| Cartridge starting to unload | Replace cartridge regularly | Colour Turbidity | Turbidity and colour are high after filter | Replace cartridge. |
| Ruptured cartridge | Ensure upstream pressure is not too high. Ensure cartridge is not damaged before installation. | Colour Turbidity | Turbidity and colour are high after filter | Replace cartridge |
| Observation: Initial pressure differential is low Possible hazards: Reduced efficacy of pre-treatment |
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| Cartridge is not sitting on the seal properly | Ensure the filter is fitted properly | Water flow Water pressure | Water pressure low | Refit cartridge |
