Today’s Ultraviolet (UV) systems are far superior to yesterday’s legacy systems. All UV systems incorporate a UV lamp(s), quartz sleeve(s), reactor chamber, elastomers and a power supply. Yesterday’s legacy systems are not quite ready to be trashed either. There are many well maintained UV systems still operating as well as they did when they were first installed. Many of these are 20 – 30 years old.
What is the secret to a long-lasting system? The answer is quite simple. A well maintained system is all that is required. A properly maintained UV system goes beyond the obvious semi-annual to annual lamp change out, cleaning of the interior of the quartz sleeve and sensor adjustment. This maintenance plan can be applied to any existing UV system.
Where do you start? First, begin with the owner’s manual. Most reputable UV manufacturers provide an owner’s manual with each unit. Inside the manual there should be a well laid out preventative maintenance (PM) schedule. If not, consider these guidelines.
Design Material – UV light is aggressive. It will oxidize or corrode just about everything it comes in contact with, including stainless steel. If a UV system is not manufactured with high quality material and it is not properly maintained, it will cause maintenance issues down the road.
UV Lamps – All UV units incorporate a single or multiple UV Lamp(s) into their design. The UV lamp is the critical component that makes a UV system. Each unit requires periodic lamp replacement. While many UV lamps will continue to operate well beyond their stated lamp life, a lamp’s performance declines if it is left to operate too long. Typically, lamp replacement should be scheduled no later than 4,000 to 5,000 hours for medium pressure systems and 8,000 to 9,000 hours for low pressure systems. Do not wait for the lamp to burn out before replacement is required. A physical process called solarization blocks the UV light from being emitted into the water stream rendering the UV system ineffective. As a lamp becomes solarized, it turns slightly brown in color and should be replaced.
Quartz Sleeve Replacement – The sleeves are probably the most abused parts within a UV system, yet they are one of the most critical components for delivering UV dosage into the process water. Quartz sleeves provide a protective barrier around the lamp so that it can operate at optimal temperature. Quartz sleeves, just like UV lamps, wear out over time. Quartz will lose its ability to transmit UV light rays into the reactor chamber. To maximize the performance of any UV unit, UV manufacturers recommend that the quartz sleeves be replaced with each lamp replacement.
Reactor Chamber – While virtually all companies that operate or maintain a UV system change out the lamps and quartz sleeves as scheduled, many companies overlook the importance of cleaning the interior of the UV reactor chamber. The inside of the reactor chamber acts as mirror to reflect UV light back into the water stream. When it becomes fouled or scaled, it loses its reflective qualities. Don’t overlook the need to physically clean the interior of a UV reactor chamber. A unit’s performance will suffer if this important step is ignored. Manufacturer’s recommendation is to drain, clean, and inspect the inside of the reactor chamber annually.
Matched Power Supply – A matched power supply is critical to the overall performance of the UV equipment. UV manufacturers have invested significantly to developing power supplies that maximize each UV unit’s output. They want the surface wall temperature of their lamp to operate at a particular temperature for a particular application. That means they have to drive the lamp at a certain voltage and current to achieve that desired temperature. When original ballasts burn out, some choose to replace them with generic ballasts, which can cause the unit’s performance to suffer. One should plan to replace their ballasts every 5 – 7 years.
Lamp Sockets – Lamp sockets are another critical component of the UV unit that is often overlooked. Lamp sockets deliver the necessary voltage to the UV lamp to produce the UV output. Over time, and like everything else, lamp sockets wear out. One should plan on replacing lamp sockets every 3 – 5 years.
O-rings & Gaskets – O-rings and gaskets are designed to maintain the hydraulic integrity of the equipment. Yet, these components are often overlooked in the annual PM schedule. Typically, elastomers are not replaced until the unit starts leaking. O-rings and gaskets are directly exposed to the UV light. In a short period of time elastomers become brittle, crack and leak. Change the O-rings once a year and the gaskets every two years to avoid leaks and any leaching of elastomer materials into your critical process systems.
Dirt & Dust – A UV unit incorporates a number of critical electrical connections into the unit design. In many cases, cooling fans are used to move air across heat sensitive components. After two to three years of continuous operation, the inside of a UV unit’s electrical enclosure will become filled with dust, dirt and grime. Add to that, a small persistent water leak and you will have quite a mess on your hands. Over time, this dirt and dust works itself into the electrical connection reducing the integrity of that connection. Set up an annual PM schedule to vacuum out the inside of each electrical enclosure. For those units that incorporate a built-in dust fan, don’t forget to clean or replace that filter as well. Your unit will be easier to maintain and will operate more efficiently.
UV Intensity Probe – One should plan on replacing their UV intensity probe every 3 – 5 years.
Stock Replacement Parts – Don’t forget to stock a few replacement lamps, quartz sleeves, and O-rings for unexpected emergencies. Quartz sleeves are fragile and tend to break when improperly handled or abused. If replacement quartz sleeves are not readily available, and one breaks, a complete water system could be shut down. Imagine the opportunity cost of lost revenue by not keeping one or more quartz sleeves on hand.
Final Thoughts – A properly maintained UV system will dramatically extend the useful life and provide the best performance of your system. The UV system is one of the most cost effective components of any water treatment system. We encourage you to follow your owner’s manuals for advice on PM schedules. If you have any questions concerning your UV system, contact us. We would be pleased to evaluate your UV equipment along with providing you expertise on your systems preventative maintenance schedule.