Disinfection Procedure - Lancaster 7-LWT-UV009 Installation, Operating And Service Manual

Disinfection Procedure:
UV disinfection is a physical disinfection process and does not add any potentially harmful chemicals to the water. As
UV does not provide a disinfection residual, it is imperative that the entire distribution system located after the UV be
chemically disinfected to ensure that the water is free from any bacteriological contaminants. The disinfection process
must be performed immediately after the UV unit is installed and repeated thereafter whenever the UV is shut down
for service, without power, or inoperative for any reason. The procedure for sanitizing the plumbing system is readily
accomplished as follows:
1. Shut off the upstream water supply that feeds water into the reactor chamber and depressurize water system.
Remove the pre-filter cartridge and fill the sump with 1-2 cups of household (5.25%) bleach (chlorine) - Do NOT use
hydrogen peroxide. At all times during this process, make sure the UV unit (and lamp) is turned on and operational!
2. Repressurize water system, open each faucet and allow cold water to run until you smell chlorine, shut the faucet
off and then repeat the process for each faucet, including hot water. You must ensure that all taps, including outside
faucets, dishwasher, shower heads, washing machines, connection to refrigerators, toilets, etc., pass chlorinated
water.
3. Once all the locations have passed the chlorine disinfection solution, you will need to leave the solution sit for a period
of 20-30 minutes. Reinstall the pre-filter cartridge into the filter, and then flush the chlorine solution from the system
until no chlorine smell is detectable. Make sure that each fixture that was disinfected in step two is completely flushed
of the chlorine solution as the consumption of the water is not advised due to the extremely high concentrations of
chlorine. It is important to remember that in the event that a UV is briefly shut down for a routine cleaning or during
power interruptions where water could have passed through the system, the aforementioned procedure must also be
followed.
Note A: The addition of chlorine (bleach) to a hot water tank that has in the past been fed with untreated raw water with
high levels of other contaminants (iron, manganese, hydrogen sulphide, organics, etc.) will result in oxidation of these
contaminants and may require repeated flushing of the hot water tank. This contingency must be dealt with independently
under the start-up procedure for any other conditioners that may form a part of the pre-treatment for the UV unit.
Note B: The above procedure (Steps 1 to 3) will result in a massive chlorine residual far in excess of the 0.5 to1.0 mg/L
typically present in municipally chlorinated water and of a magnitude consistent with the minimum 50mg/L chlorine
solution recommended for the disinfection of distribution systems known to be contaminated. Do not consume water until
complete system has been flushed.
• Always disconnect power before performing any work on the disinfection system.
• Regularly inspect your disinfection system to ensure that the power indicators are on and no alarms are present.
• Replace the UV lamp annually (or biennially if seasonal home use ) to ensure maximum disinfection.
• Always drain the UV chamber when closing a seasonal home or leaving the unit in an area subject to freezing
temperatures.
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