- Alarm contact terminals 16 and 6 (normally closed and common) can be used to break the red 24V power wire to the thermostat. 16 and 6 effectively works as a switch, in a normal condition 16 is connected to 6 and when in alarm 16 is disconnected from 6.
- Some residential furnaces have a fan rundown mode where the fan will run even after a signal from the thermostat, these furnaces sometimes have a DIL switch to program this feature or alternatively power can be broken to the furnace alternate to the thermostat by breaking the neutral power to the furnace through terminals 16 and 6.
