I have a Vaillant EcoMax Pro condensing boiler and also a Superduty fast recovery hot water cylinder. When the boiler was installed the installer set the boiler temp to 65C. A year later, a different guy from the same firm came round to do the 1 year warranty check and insisted it should be 70C. What is the optimum value, if there is such a thing? Or would I be right in thinking that it's the return temp that's more important, and that it should be 55C or less?
If it's the return temp that's important, then I have a supplementary question... I understand that hot water in a cylinder should be heated to
60C in order to prevent the growth of Legionella bacteria. Is this correct, and if so, how do I reconcile the two requirements -- return at 55C or less, but hot water >= 60C?Ta,
Steve S