Frequently Asked Questions

How do I size a UV system into my home?

If you need to figure out the flow rate in gallons per minute of a steady flow in to a holding tank, or open discharge:

To estimate the flow rate of water into your home:

Make sure no water is running in the house
Use the faucet closest to the water source (pump, tank or pipe)
Open the faucet completely and measure the time it takes to fill a one US gallon container
Divide 60 seconds by the time it took to fill the container flow rate

EXAMPLE: If it takes 20 seconds to fill a 1 gallon container, the flow rate is 3 gallons per minute.

All Sterilight system can be installed both vertically and horizontally. Care must be taken however, when orienting the reactor.

If you have a "U-shaped" style reactor (ex. Sterilight system with both the inlet & outlet port on the side of the chamber - the "Q" series) please see the diagram below:

If you have an "axial" style reactor (ex. Platinum, Cobalt or Copper series) please see the diagram below:

As the UV lamps and /or sleeves need to be periodically removed from the reactor chamber, you must leave at least double the length of the disinfection system to facilitate removal. A typical 5 USGPM UV system would require approximately 45" of space either vertically or horizontally.

We do recommend that you install a flow restrictor on your Sterilight system, that way you can be sure that your disinfection is not being compromised.

A Sterilight system requires two water connections and one electrical. Very simple. You can install any of the Sterilight systems either vertically or horizontally HOWEVER there is a right and a wrong way to do this. If you are going to install a Sterilight system vertically please have the system set up so that the lamp slides down into the system (in other words the lamp goes in at the top) or if you are going to install the system horizontally, ensure that the inlet/outlet ports are facing up (toward the ceiling). Please ensure that the UV system is installed prior to the branching off of hot and cold water lines.

The following picture is an example of how you should install your Sterilight system. Please keep in mind that in the picture below all different kinds of options are indicated. This is merely a RECOMMENDATION. What we would like to get across is that the UV must be the very LAST piece of water treatment equipment.

No, Sterilight systems are designed with inlet/outlet ports correctly sized for the specific application. As an example, the 8 USGPM system comes with 3/4" ports. The typical pressure drop on this system would be 2-3 psi.

Although not essential, the installation of a simle by-pass assembly would allow for emergency use of the water in case the UV unit was required to be removed from service. A simple by-pass assembly with three isolation valves can be installed quite easily.

UV systems are extremely economical to operate. A typical 8 USGPM whole house UV system operates on the same power requirements as a 40 WATT light bulb.

The UV system does require constant power, both voltage and frequency, for the system to operate effectively. To compensate for variations in power supplies, the Sterilight systems incorporate proprietary ICE ballast technology. The ICE ballast provides a constant output voltage regardless of variations in input frequency or voltage. This results in consistent UV ouput and consistent UV dose. It is recommended to install the UV on a separate outlet protected by GFI (ground fault interrupter).

A solenoid valve is an electrically-activated mechanical valve that opens and closes when power is applied to it. This kind of valve can be installed and wired into a Sterilight system which is monitored. If the UV intensity were to drop below the recommended level the solenoid would then be activated and automatically shut down the flow of water. This will keep contaminated water from getting through the UV system. A solenoid can be hooked up to a Sterilight system either by dry contacts (the Platinum, SUV and SUVAM systems all come equipped with dry contacts), or directly into the Sterilight system (Silver and GOLD series can be hooked up directly to a solenoid; outside power does NOT need to be brought to the solenoid).

A Sterilight UV system is there to protect your water from pathogenic microorganisms, BUT there is the potential for harmful microorganisms to already be present in the water lines. The water lines then need to be disinfected upon installation of the UV system.

A simple way to introduce a disinfectant (chlorine) into the lines is via the filter. Once the Sterilight system has been plumbed in simply remove the cartridge from the filter housing and fill the housing halfway with household bleach (bleach contains 5.25% chlorine). With the Sterilight system ON, turn the water on and ensure that at each and every tap a chlorine smell is detected. Leave the bleach in the lines for at least one hour. Drain the chlorine from the lines.

Detailed Disinfection Procedure

Does my water need pretreatment?

It is very important to reduce the turbidity levels in the water prior to the Sterilight UV system.

What is turbidity? Turbidity consists of small suspended particles that eventually fall out of solution. If you ever draw a glass of water from a faucet and you see those very small particles floating to the bottom of the glass, that's turbidity. You are more likely to see high levels of turbidity in surface water than in ground water.

Turbidity is a huge concern when it comes to disinfection as these small suspended particles can shield microorganisms from disinfection, whether it's physical disinfection or a chemical type of disinfection. We recommend that the turbidity level be below 1 NTU (nephelometric turbidity units).

Turbidity levels less than 5 NTU's do not necessarily affect UVT levels but it will affect disinfection efficacy.

R-Can offers a number of water filters that can reduce the UVT levels to acceptable levels.

UV transmittance at 254 nm (which is the wavelength of light that UV lamps operate at) is a measure of the fraction of incident light transmitted through the water column. The UV transmittance is the ratio of the light entering the water to that exiting the water. The UVT is usually reported for a pathlength of 1 cm. As UV absorbance increases, the UV transmittance decreases (USEPA UVDGM 2003).

UVT is measured using a spectrophotometer. High levels of color &/or tannins will cause a decrease in the UVT level. If the water cannot transmit the UV light, than the UV cannot disinfect efficiently

If you have high colour in your water it is most likely a concentration of tannins. High tannin levels are found in most surface water supplies and some groundwater or simply in waters where large quantities of vegetation have decayed. Unfortunately tannins cannot simply be removed from water by a physical means of filtration.

Tannins can be described as a colloidal suspension as it carries a negative charge and therefore will not simply fall out of solution like turbidity does. Tannins are water soluble, organic compounds formed in the decomposition of organics. It can cause a slight yellowish color to the water and will rapidly decrease the level of UVT in your water as the tannin level increases.

The most efficient way to remove tannins from drinking water is by way of an anion exchange system. Hardness is removed from water via a cation exchange system or softener, as the hardness compounds need to be exchanged with sodium ions in order for the hardness to be removed. Tannin removal systems work the same way but with a slightly different resin than a softener. Softeners exchange cations for cations (positively charged ions, like calcium and magnesium in exchange for sodium ions) and tannin removal systems exchange anions for anions (negatively charged ions like tannins in exchange for chloride ions).

With chemical disinfection, such as chlorination, the taste and odor of your water will change (depending on chlorine levels water can smell and taste of bleach) and disinfection by-products will be produced. A few examples of chemical disinfection by-products (DBP) are trihalomethanes and haloacetic acid. Both of these DBP's can be carcinogenic when ingested at high levels. The pH and conductivity of drinking water also changes when chlorine is added.

UV is a physical type of disinfection. This means that the UV will have an effect on the microorganisms in the water only. The water will not change chemically, nor will the taste and odor change. The water may elevate in temperature if the water has been left stagnant in the UV reactor (ie. During times of little or no use - during the night).

What is UV light?

UV dose is the energy that is coming off the UV lamp over a specific time period. Therefore, UV dose (or fluence) is a product of UV intensity and time. Dose is usually measured in milli joules per square centimeter. Each Sterilight system is rated to disinfect your water at specific flowrate, under specific water quality conditions to give a UV dose of 30 mJ/cm² at the end of the lamp life (which is one year).

If you were to run say 10 USGPM through a 5 USGPM Sterilight system (ie. S5Q-PA) then you would only be receiving HALF the dose that the system is rated at because you doubled the flow. It works the other way as well. If you were to have a 12 USGPM Sterilight system installed (ie. S12Q-PA) but you were only running 6 USGPM through it then you would be receiving double the UV dose as you are increasing the water's exposure time to the UV light.

The UV industry standard for dose is 30 mJ/cm² at the end of lamp life (EOL) however different validation protocols will specify different dose values. Please refer to the compliance page for more information on the various validation dose requirements.

Log inactivation is the inactivation of microorganisms on a logarithmic scale. Microorganisms must be considered on a logarithmic scale due to their high numbers.

A bioassay test is a "comparison of disinfection achieved in a UV reactor with that achieved under well controlled bench conditions" (Tom Hargy, IUVA presentation 2003).

The use of UV technology for drinking water disinfection does come with limitations. In order for a particular system to be used for the treatment of drinking water, in regulated applications, it must have proof of performance. Proof of performance can be described as third party validation. This type of validation requires a third party expert to witness a bioassay test on the UV system in question, according to a specific UV testing protocol. There are several different UV validation protocols available depending on the type of UV system being considered.

You never want to expose your skin or eyes to the light from a UV system. UV light is non-visible however it can be harmful, similar to the harmful effects of UV light from the sun. UV lamps can actually cause a severe sunburn-like effect if skin is exposed for long periods of time.

Always ensure that you are wearing some type of protective glasses (ie. Safety glasses or sunglasses) when working on a UV system and the lamp is exposed. You want to make sure that you do not touch the UV lamp with your fingers as the oil from your hands will form a residue on the lamp and can potentially block UV light.

Are Sterilight systems difficult to maintain?

This will depend on the model of Sterilight that you have purchased. R-Can sells UV system from 0.5 USGPM to 1,000 USGPM and with a variety of different options. We offer:

base models: these systems have an audible and visual alarm for lamp failure
monitored systems: these systems come equipped with a UV sensor so if the intensity drops below a safe level the customer will get an audible and visual alarm
Platinum systems: these systems equipped with both a UV sensor and a controller which gives a digital display of all aspects of your system
Municipal systems: these are equipped with a PLC and touchscreen

Therefore, depending on the model will depend on how you will know that your system is working. Please keep in mind, if the Sterilight system that you have does NOT have a UV sensor then your system is only monitoring the operation of the UV lamp. You could technically paint the quartz sleeve black on a non-monitored system, and you would never know. It only is monitoring whether or not the lamp is on.

The UV light that is inactivating microorganisms in water is non-visible light, therefore the blue light that you see coming off a UV lamp is not what's doing the work. A UV lamp can be described as a low pressure mercury vapor lamp, which means it fires via mercury vapor. Over the course of a year that mercury is being used up resulting in a slight decrease of UV intensity. At the end of one year a Sterilight UV lamp has decreased in it's intensity by approximately 20%. We strongly recommend that UV lamps be changed on an annual basis.

R-Can has technical assistance on hand 5 days a week from 8-5pm Eastern Standard time. It would be most helpful if you call when you are actually standing in front of the system as this will make troubleshooting much easier. You can also send an email to our technical department. If you are sending an email about a technical problem and you do have a picture of the system handy, that would also help. If you would like to try and troubleshoot on your own please refer to the service page for your product.

If the quartz becomes stained, remove the sleeve from the reactor chamber and clean the OUTSIDE with a commercially available scale remover, such as Lime-Away or CLR. If the inside of the quartz sleeve does become wet, ensure that it is thoroughly dried before putting the Sterilight system back together.

All Sterilight systems are rated for a 4-log inactivation of bacteria, viruses and protozoan cysts under specific conditions. This rating is at a specific flow rate, and water quality. It is a good idea to have your water microbiologically tested prior to installing a UV system. We do suggest that if your water has bacteria counts in excess of 1000 CFU/10 mL that you do a bit of research with regards to what could be causing such high bacteria counts and that you oversize your UV in order to ensure a high UV dose being delivered to your water supply.

Microorganism Destruction Chart

Cryptosporidium and Giardia are what is called a protozoan cyst. Protozoa can be described as microscopic, single celled microorganisms which live in water and are quite a bit larger in comparison to other microbes. The majority of protozoan cysts are parasitic. Both Cryptosporidium and Giardia are parasitic. These organisms are in a dormant phase when in water but when they enter a host (being any kind of mammal) they release colonies and begin to breed, ultimately causing severe diarrhea and dehydration over a prolonged period of time.

Cryptosporidium and Giardia were not microorganisms of concern until approximately 10 years ago when Milwaukee was hit with a waterborne disease epidemic. Milwaukee drinking water is surface water, which had become contaminated with high concentrations of Cryptosporidium at the time. Over 100,000 people came down with Cryptosporidiosis and over 400 people died. The USEPA recognized that they needed to consider these organisms and include them within their drinking water guidelines. Testing was done and it was found that chlorine was NOT effective against either of the protozoa. Testing was then conducted using UV technology with initial failure due to improper test procedures. Ultimately it was proven that UV is in fact very effective against Cryptosporidium and Giardia. The dose levels required to inactivate these cysts are actually quite low; less than 10 mJ/cm² for 99.9% reduction of both Cryptosporidium parvum and Giardia lamblia.

Protozoan Cyst Article

UV does not kill microorganisms like chlorine does, but instead UV inactivates them. UV light at a specific wavelength of 254 nm is readily absorbed by the genetic material of microorganisms. The DNA strand is coded with a specific sequence of something called base pairs. The sequence of these base pairs codes for certain characteristics. UV light at 254 nm is readily absorbed at the point on the microorganism's DNA strand which codes for reproduction. A microorganism that cannot reproduce, cannot make colonies and therefore cannot infect when consumed. In other words, the microorganisms have been sterilized or neutered. They will eventually die off.

The picture on the left shows a DNA strand of a microorganism. You can see where the UV light is absorbed and how a blockage is formed, causing the microorganism to become sterile.

If you have a private well the Ontario Health Board will test your water for bacteriological safety free of charge. The results will simply consist of counts of Total Coliforms and E.coli. If there are counts of either, your water will be deemed "unsafe". You can pick up bottles at the various locations of the Health labs.

There are many analytical laboratories available for the analysis of chemical parameters in your water. Simply look up 'analytical laboratories' in the phone book or on-line. Keep in mind that you will have to advise the lab as to what parameters that you want tested. If you have questions with regards to which parameters you need to have tested, please contact R-Can directly.

Why do I need to disinfect my water supply?

Our municipalities work very hard to provide safe, disinfected water for their customers. This is quite evident when you consider the difficulties involved in providing safe drinking water through a vast distribution network. If you use water that comes from a municipal water supply and wish to provide your family with an added "peace of mind", then we believe a UV system acts as an inexpensive insurance policy against the possibility of drinking bacteriologically contaminated water.