Am I at risk of legionella related illness with a heat pump?
Legionella bacteria cannot survive at temperatures over 60 degrees. Our normal control systems and immersion heater will raise the temperature of the hot water cylinder to over 60 degrees periodically to pasteurise the tank. To save electricity we time this so that the immersion heater only needs to raise the tank the final 5 degrees (from 55 to 60 degrees).
