<P> However, legionella can be safely and easily controlled with good design and engineering protocols . For instance raising the temperature of water heaters once a day or even once every few days to 55 ° C (131 ° F) at the coldest part of the water heater for 30 minutes effectively controls legionella . In all cases and in particular energy efficient applications, Legionnaires' disease is more often than not the result of engineering design issues that do not take into consideration the impact of stratification or low flow . </P> <P> It is also possible to control Legionella risks by chemical treatment of the water . This technique allows lower water temperatures to be maintained in the pipework without the associated Legionella risk . The benefit of lower pipe temperatures is that the heat loss rate is reduced and thus the energy consumption is reduced . </P>

When does a water heater become a boiler