A boiler interlock is a mechanism that allows the boiler to shut off when it does not need to release heat. It is both a method of controlling heat and a safety feature.
Where the system has a thermostat that measures the temperature, it will activate the boiler interlock so that the boiler will stop functioning when the room achieves a certain temperature. If there is no thermostat, a boiler interlock can be created by using motorized valves or a boiler energy manager. Traditional radiator controls cannot prevent the boiler from releasing heat the same way that boiler interlock can.