Thanks Chuck.
I would be suspicious of electronics humming or buzzing. Boxes of electronics like central heating control units and consumer units should not hum or buzz? Surely, this is indicative of a fault? But this hum was heard...
HIUs contain some electronics, which need a power supply that may hum all the time but this should be very quiet. There will also be a pump, often inside the HIU, that circulates water through the heat exchanger and around the...
Last year, my wife and I viewed four apartments in a block of apartments that had a district/community heating system. Each apartment therefore had a heat interface unit (HIU). It was my first experience of this type of heating and I...