Teaching an Old Dog New Tricks

May 31, 2006

About the author: Adam Donnellan is vice president at Sunlight Systems Ultraviolet. He can be reached at [email protected].

All water systems need to be maintained, and this is where the true value of having a water treatment professional comes into play.

Similar to any water equipment that requires service and replacement parts, UV systems can present a multitude of issues that require the expertise of a well-prepared technician.

For any UV service call, the technician needs to have access to a variety of parts: lamps, quartz sleeves, O-rings, washers, ballasts, alarm boards, monitors and other unique items. Many of these items are proprietary or difficult to track.

Problems arise because there are hundreds of different systems from different manufacturers, many of whom are no longer in business. Often, these obstacles force technicians to scrap the existing system and install a new one at a great cost to the customer.

As UV systems become more complex in order to meet various regulations, so do the problems associated with their maintenance. Most calls involve preventative maintenance; however, on occasion, the technician will encounter more complicated issues.

A good rule of thumb is that every year (9,000 hours), the UV lamp should to be replaced and the quartz sleeve cleaned. This is usually a simple task if the servicing company installed the original equipment. In the event of a system failure, however, the service technician will need to gather a lot of information in order to determine what is wrong and what parts are needed.

Typical Calls

Case 1. A technician arrives on site to find a lamp out. This will be signified by an extinguished LED, an audible alarm, or if supplied with a solenoid valve, no water.

The first course of action is to try a new lamp. After disconnecting the power, the lamp should be swapped with a new one. Hopefully, this will get the system up and running once re-powered.

If the lamp remains off, then the power supply (ballast) may be damaged. In this case, a new ballast or ballast pack will need to be installed.

Case 2. The system has a UV monitor. The water is off due to the solenoid valve closing. The lamp seems to be on, but it may be old. The technician replaces the lamp, but still, there is no water.

This could be due to an issue with the sensor or the solenoid; either may be damaged. The solenoid can be checked by bringing power to it. Because solenoid valves are normally closed, bringing power to them should open them.

The problem also could have occurred because the water has become too warm. High heat will cause the actual UV output to fall off, and thus close the valve. This happens at many locations where the water is not constantly used. Flushing the water and observing the UV reading can test this.

If none of the above works, the technician will have to install a new sensor, sensor glass and monitor.

Aquiring New Parts

A good UV manufacturer will have access to most commercially available parts even if they are proprietary. Most UV manufacturing companies work together and provide information on authorized resellers and how to source parts. This provides the water treatment professional with a one-stop-source for all parts.

In order to describe what is needed, the technician must gather and record the relevant information for the purchasing department. While having access to the original O&M manual is ideal, in most cases, the manual will have disappeared. The following is a list of items that will need to be recorded.

1. Manufacturer’s name

2. Model number

3. Number of lamps

4. Type of lamp (Photo 1): a) part number on the glass; b) overall length from the base to the pins; c) arc length; d) pin configuration; e) number of wires running down side; f) color of bases; and g) other notations on the glass.

5. Type of quartz sleeve (Photo 2): a) outside diameter; and b) Type: open-ended or closed-ended (domed).

Upgrading Residential & Commercial Systems

In many cases, the UV system will require some type of electrical repair. The UV system is basically made up of a UV lamp and a ballast that powers the lamp. In addition, the UV system may have lamp-out electronics, audible alarms or UV monitoring. In an effort to minimize the electrical aspect of fieldwork, many installers find it easier to retrofit all of the electronics.

Upgrading Industrial Systems

While the majority of systems in the field are single-lamp vessels, there are many commercial and industrial installations that have multiple lamps. The same concepts apply to maintaining and sourcing the lamps and sleeves, but there are other issues that can be addressed.

In a recent application, an end user had an eight-lamp UV system. The electronics were fairly old (eight years), and the ballasts and other electronics started to fail. The actual stainless steel vessel, however, was in excellent condition.

The water treatment professional came up with a plan to keep the existing stainless steel chamber but change the electronics and lamps.

The client decided not only to get new electronics, but also to switch to a more powerful lamp and corresponding electronics. This not only would provide a greater kill, but would actually allow more water to be pumped.

Because the newer lamps were twice as powerful as the originals, the client was able to increase volume and the plant’s overall productivity, and because the vessel did not need to be re-piped, there was limited down time.


A service technician’s time is valuable. Hopefully, the issues outlined in this article have provided some useful tips and new ideas on how to maintain and upgrade existing systems in the field.

About the Author

Adam Donnellan

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