NTI S Series Installation And Operation Instructions Manual

Contents

Trin & Stor │ Installation and Operation Instructions Indirect Water Heaters6Legislation and Guidelines - At the time this document was written, standards andguidelines regulating the prevention of Legionella in the United States and Canada weremostly voluntary. The American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.(ASHRAE) is currently in the process of converting its guideline entitled "Minimizing the Risk of LegionellosisAssociated with Building Water Systems" (ASHRAE Guideline 12-2000) into an official standard. Consult withyour local authorities as to recommended guidelines for controlling Legionella in potable water systems.Storing water at temperatures >140°F may not be permitted in some States, so check withthe authorities having jurisdictions. In Canada, recent changes to the National PlumbingCode requires that domestic hot water be stored at or above 61oC (140oF) and then mixed down to safetemperatures at the tank outlet.General Guidelines - In the absence of a National standard or local codes, the following are general guidelinesfor “good practice” on maintaining, monitoring and operating your potable water system:• Store domestic hot water at temperatures > 61oC (140oF).• Store and distribute cold water at temperatures below 20oC (68oF).• System supply for uses other than high temperature applications typically greater than 46oC (115oF) shall beequipped with a thermostatic mixing valve on the hot water outlet to reduce potential scald hazards.• Clean aerators and nozzles on water fixtures on a regular basis to reduce scale build-up.• Clean storage tanks and remove sediment. Flush storage tanks and piping systems regularly for 10-30minutes at high water temperatures (depending on guidelines used) to rid the system of sediment and scalethat develops, typically in the bottom of storage tanks where water temperature is coolest; and piping runswhere water can stagnate.• Abandoned water lines should be capped off at the distribution main, not at the most convenient place.• Avoid dead-ends in piping system. If unavoidable, provide a drainage port in these areas at the lowest pointto flush out stagnant water regularity.• Insulate Domestic Hot Water recirculation lines and keep pipe runs as short as possible.• Recommend annual water testing of water in your tank and piping system(s) to monitor water conditions.• Keep a maintenance record of when your indirect water heater and storage tank were cleaned, pipingsystems flushed and who did the service work.Table 1-4 How Water Temperature relates to Legionella and Scald HazardWater Temperature 1 Legionella Bacteria 1 Water Temperature 2,5 Exposure Time vs Burn 5158-176oF 70-80oC Disinfection range 158oF 70oC 1 second - 2nd or 3rd degree burn140-149oF 60-65oC Bacteria die within minutes 140oF 60oC 5 seconds - 2nd or 3rd degree burn122-131oF 50-55oC Bacteria die within hours 131oF 55oC 5 seconds - 1st degree burn68-113oF 20-45oC Bacteria thrive and multiply 122oF 50oC 1 minute - 1st degree burnbelow 68oF below 20oC Bacteria is dormant 111oF 44oC 5 hours - 1st degree burn 3,4Notes:1 Published by Chartered Institute of Plumbing and Heating Engineering, Databyte series, "Safe Hot Water Temperatures".2 The elderly and small children are susceptible to bad burns at shorter exposure times than listed in this table.3 A thermostatic mixing valve should be installed on DHW storage tanks when outlet temperatures exceed 115oF [46oC].4 Typical water temperature for bathing or showering range between 98-113oF [37-45oC].5 Temperature-Time-Burn Chart published by John Hopkins University, excluding notes.