A humidification system is provided for a respiratory system is provided with a controller having two processors that monitor the operation of each other and of heating elements in the respiratory system to provide CPU redundancy and heating element control. Each heating element is provided with two control paths, for example a relay and a triac connected in series with the heating element and a power supply. Each heater element has one control path connected to a first one of the processors and at least one heating element has at least one control path connected to a second one of the controllers. A hardware watchdog monitors the operation of the first processor, and can be triggered by a signal from the second processor, in response to which it can disable all heating elements.
