Preventive Checking preventive measures Corrective action Causes measures What to check Signs that action is needed Event: UV DOSE TOO LOW – cont’d C1.7.2 Regularly check Water flow Flows are low or Replace or repair and record water records. very changeable. the flow controller. Germs flow to make sure exposed to Water Reduce the water it meets too little light temperature is flow if the water manufacturer’s because thermometer low enough to temperature is too requirements. water flow is readings of water affect lamp low. too fast or Follow temperature. intensity. Add chlorine to the water is too manufacturer’s storage tank until cold. instructions about satisfactory water adjusting water quality can be flow if the water is restored, or close cold. the supply down and arrange for another supply of water. C1.7.3 Install a filter See C1.5.1–C1.6.1. before the UV Water disinfection unit discoloured or and make sure it cloudy. works (see C1.5.1–C1.6.1). C1.7.4 Install an alarm Alarm. Alarm is triggered Make arrangements that warns that to get a more Power supply Power to UV No electricity the power has reliable power failure. disinfection unit. reaching the UV failed, and shuts supply. unit. off the water flow. Add chlorine to the Install a stand-by storage tank until generator. satisfactory water quality can be Regularly restored, or close maintain the the supply down power supply (if and arrange for you have a diesel another supply of generator, for water. example).
Causes Preventive measures Checking preventive measures Corrective action What to check Signs that action is needed Event: UV DOSE TOO LOW – cont’d C1.7.2 Germs exposed to too little light because water flow is too fast or water is too cold. Regularly check and record water flow to make sure it meets manufacturer’s requirements. Follow manufacturer’s instructions about adjusting water flow if the water is cold. Water flow records. thermometer readings of water temperature. Flows are low or very changeable. Water temperature is low enough to affect lamp intensity. Replace or repair the flow controller. Reduce the water flow if the water temperature is too low. Add chlorine to the storage tank until satisfactory water quality can be restored, or close the supply down and arrange for another supply of water. C1.7.3 Water discoloured or cloudy. Install a filter before the UV disinfection unit and make sure it works (see C1.5.1–C1.6.1). See C1.5.1–C1.6.1. C1.7.4 Power supply failure. Install an alarm that warns that the power has failed, and shuts off the water flow. Install a stand-by generator. Regularly maintain the power supply (if you have a diesel generator, for example). Alarm. Power to UV disinfection unit. Alarm is triggered No electricity reaching the UV unit. Make arrangements to get a more reliable power supply. Add chlorine to the storage tank until satisfactory water quality can be restored, or close the supply down and arrange for another supply of water.