legionella

Hi, I have a new installation of an Air Source Heat Pump (Grant UK Aerona), and a horizontal Tempest 200l pressurised cylinder. It has a single immersion heater, which is controlled by a Timeguard FST77 7 Day Fused Spur Timeswitch, and the whole system is controlled by a ESI ESCTD Mechanical...

Hi, I've got a rental flat that's been empty 8 months, it's got an electric shower and electric water cylinder. Do I need to drain the system to avoid legionaires disease risk? If so how? Thanks