Why Are the Baseboards or Radiators Hot Even Though the Thermostat is Set Higher than Room Temperature?
If electrical power switch to a hot water heating boiler is in the “on” position (see ELECTRICAL POWER SWITCH FOR HEAT) and the room thermostat is set above room temperature, the heating system (hot water or steam) boiler or (warm air) furnace should not run. But for hot water heating systems (baseboards, radiators), other defects could cause or permit hot water to circulate through the heating system by “gravity” (convection, warm water rising on its own through the heating piping) even though the thermostat is not calling for heat. The problem, if this is occurring, is usually that a check valve (photo above-left) (found internal to some circulator pumps, or external as a physical device) intended to prevent hot water from circulating on its own – when the circulator pump is off – is either set to a “forced open” position, or it has become defective (less likely). If that’s the problem (diagnosed by a heating and service technician) then the valve or circulator needs to be replaced.