A UV disinfection unit does its job only while the lamp is producing enough light and the quartz sleeve around it is clean. Most of the upkeep is simple, but it is easy to forget because the unit often gives no obvious sign that it has stopped working well. This guide lists what you own between service visits and what to write down so the record is useful.
Know what the unit reports
Find the indicator light or display on the unit and learn what each state means from the manual. Many units show lamp status, power, and sometimes an alarm when lamp output drops. Read the display once a month and note any change. An alarm is not a diagnosis, but it is a reason to call the service provider rather than wait for the next scheduled visit.
The lamp and the sleeve
The lamp sits inside a quartz sleeve that keeps the water from touching it directly. Over time, minerals and deposits can build up on the sleeve and block light. The manufacturer will list a lamp replacement interval and a cleaning approach for the sleeve, so follow that list. Do not substitute a lamp of a different type or wattage unless the manufacturer's documentation says it is equivalent. Ask the service provider to confirm the correct lamp part number and record it with your paperwork.
Flow and water quality
UV units are rated for a maximum flow. If flow regularly runs above that rating, the water may not receive enough light exposure. Check whether the design includes a flow restrictor or a pressure setting, and whether your household uses water in bursts that exceed the rating, such as filling a large tub while running a laundry cycle. Upstream filtration matters too. If the water becomes cloudy or carries more sediment, the sleeve can foul faster, so note any change you see at the tap.
Keep a log that is actually useful
A useful log has five columns: the date of each check, the indicator reading, any alarm, what you cleaned or changed, and who did it. Keep the install paperwork and the lamp part number with the log. When a technician asks what has happened since the last visit, the log answers the question. Store it where you will find it, such as in the same folder as the warranty and the service contact.
When to call the provider
Call if the alarm stays on after a documented cleaning, if the lamp fails earlier than the manufacturer's listed interval, if the water changes in taste or clarity after service, or if the power supply to the unit flickers. Do not open the unit or handle the lamp while the unit is powered. Confirm the lamp is off and cool before any work.