> 50-53C is common to avoid risks of scalding but some are set as low as 45
Wait what, isn't the minimum temperature where Legionella will die around 60°C? Are you talking of a country where they (noticeably) chlorinate the water? I thought that was very uncommon, except for Southern Spain and Italy. If you set your boiler to 45°C in a country with (nearly) unchlorinated water you'll have a nice Legionella culture after your 3 week vacation.
My water tank and hot tub had "self-cleaning" cycle that would heat up and circulate water to prevent bacteria buildup regardless of what temperature it was set to.
Wait what, isn't the minimum temperature where Legionella will die around 60°C? Are you talking of a country where they (noticeably) chlorinate the water? I thought that was very uncommon, except for Southern Spain and Italy. If you set your boiler to 45°C in a country with (nearly) unchlorinated water you'll have a nice Legionella culture after your 3 week vacation.