Well, all this got me thinking. I got the following off the OSHA web site. Based on this, I am going to do a good flush and then increase temperture 5 degrees. I don't have a real concern about contamination, but flushing the heater should be done periodically to keep the heater operting efficiently and 5 degrees will not cost that much. Concern goes to zero. Also, I'm not crazy about adding chemicals to my water system, so no 'deep cleaning' for me.
Q. Can Legionnaires' disease be prevented?
A. Yes. Avoiding water conditions that allow the organism to grow to high levels is the best means of prevention. Specific preventive steps include:
Regularly maintain and clean cooling towers and evaporative condensers to prevent growth of LDB. This should include twice-yearly cleaning and periodic use of chlorine or other effective biocide.
Maintain domestic water heaters at 60°C (140°F). The temperature of the water should be 50°C (122°F) or higher at the faucet.
Avoid conditions that allow water to stagnate. Large water-storage tanks exposed to sunlight can produce warm conditions favorable to high levels of LDB. Frequent flushing of unused water lines will help alleviate stagnation.
Q. Do you recommend that I operate my home water heater at 60°C (140°F)?
A. Probably not if you have small children or infirm elderly persons who could be at serious risk of being scalded by the hot water. However, if you have people living with you who are at high risk of contracting the disease, then operating the water heater at a minimum temperature of 60°C (140°F) is probably a good idea. Consider installing a scald-prevention device.
Q. What can be done if a water system is already contaminated or is suspected of being contaminated?
A. Special cleaning procedures and water treatment can reduce LDB in water systems. In many cases, these procedures involve the use of chlorine-producing chemicals or high water temperatures. Seek professional assistance before attempting to clean a contaminated water system.
Q. Can my home water heater also be a source of LDB contamination?
A. Yes, but evidence indicates that smaller water systems such as those used in homes are not as likely to be infected with LDB as larger systems in workplaces and public buildings.
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