Technical Support

Every month our customer service department will post one new question that has come up during the month that they believe will may help you troubleshoot an existing product or provide insight on a new product available.

Q: Are there any guidelines on hot water storage temperature and Legionellae?
A: Yes. If you refer to ASHRAE Guideline 12-2000 (“Minimizing the Risk of Legionellosis Associated with Building Water Systems”), in Section 4.1.6, it states "Where practical in health care facilities, nursing homes, and other high-risk situations, cold water should be stored and distributed at temperatures below 20°C (68°F), while hot water should be stored above 60°C (140°F) and circulated with a minimum return temperature of 51°C (124°F). However, great care should be taken to avoid scalding problems. One method is to install preset thermostatic mixing valves." You often see commercial building designs to include an ASSE 1017 approved master mixer to temper from the stored 140°F to 120°F for the domestic hot water loop. Often you will see additional devices, such as an ASSE 1070 approved Temperature Limiting Device at the lav's and an ASSE 1016 approved Shower Valve for their respective applications.

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