Domestic Hot Water Return Temperature
In these cases consider sizing the piping to keep velocities lower than two feet per second.
Domestic hot water return temperature. Domestic hot water recirculation steps. Typically for systems where the distance from the hot water heater to the consumption fixtures exceeds 25 30 m. Calculate the gpm required using a 10 f δt or other value as determined by the engineer. Part 1 find the pump gpm determine the heat loss of the total supply pipe using tables or rules of thumb.
Even as clean water is a typical family of three wastes 16 000 litres of water and spends a whole 24 hours a year waiting for hot water at the tap or in the shower. Hot water water at a temperature greater than or equal to 110 f 43 c. The recirculating pump keeps hot water moving through your home s hot water pipes at all times on demand or set for specific hours via a timer. Hot water should not be stored at temperatures below 60 oc 140 of to avoid the risk of legionella contamination.
In some unique cases domestic hot water temperatures can go higher than 180 f booster heaters and steam heat exchangers or with some types of heat recovery systems or other industrial or institutional piping systems. Time for hot water to reach fixture without circulation pump. But if a 45 c return temperature can be achieved along with the specification of pipes two sizes smaller then heat losses are reduced by 43 for an unchanged insulation specification. A return circulation pipe is sometimes provided in a hot water system where it is desirable to have hot water available continuously at the fixtures.
Typically most new heat networks operate at around 5k delta t commonly 80 75 c because of poor design and or commissioning. The plumbing codes define hot water as follows. This does not mean it is good design to store the hot water at 110 f. 1 us gpm 0 0630.
For canteens and professional kitchen temperatures of 65 oc are often required to satisfy hygienic standards. Hold the thermometer in the hot water flow for one minute record the temperature on the thermometer it should be a minimum of 50 degrees celsius after one minute if it is below this advise whoever oversees the site so the necessary actions can be taken to remedy the issue. With a hot water recirculation system you can guarantee your customers the luxury of hot water in an instant becoming an increasingly scarce resource we waste millions of m3 every. No there is no code language addressing a minimum domestic hot water storage temperature.