Hi - turned thermostat down to shut off furnace but noticed older orange wall (forced hot water) wall Chromalox EDB-2 has light on in 'min to max' range up to 90C. Tried to turn manual knob down (to left to lower the 80ish setting) but it doesn't seem to want to...Temp is showing 124, pressure 18. Is there a danger with light on? How can I turn heat off and will hot water pipes in basebd still feel hot? Much thx!