4.4.5Water Out Indicator
This indicates that there is insufficient water in the humidification chamber.
The humidifier measures the amount of power used to obtain the chamber temperature. If a lower than expected amount of power is used, a 'water out' alarm is generated. It may take 15 minutes or longer to generate an alarm especially if there is a disturbance (change in flow).
This alarm can be cancelled by pressing the mute button. If however the water out condition remains, the humidifier will alarm again.
4.5Operational Alarms
These alarms are generated if problems occur with the operation of the humidifier.
4.5.1Temperature Indicator
This alarm will occur if the displayed temperature is too high, or if the delivered temperature (Invasive mode only) has been low for a period of time.
High temperature:
The humidifier will immediately alarm if at any time the displayed temperature exceeds 41 °C, or if the airway temperature exceeds 43 °C. If either of these high temperature alarms occur, the humidifier will immediately shut down the heater wire and heater plate.
Low Temperature:
The low temperature warning (visual only) and alarm (visual and audible) are active only when the humidifier is in Invasive mode. Both are disabled during
The low temperature warning and alarm operate by monitoring the displayed temperature. If the displayed temperature is below 35.5 °C for 25 seconds, the temperature indicator will light, and act as a warning to the user. If the temperature remains below this level for too long, then a Temperature Alarm is activated. The time taken for the humidifier to alarm is dependent on how far below the 35.5 °C threshold the displayed temperature is. Figure 4.3 shows the relationship between temperature, a temperature warning and the time before a temperature alarm:
MR850 Technical Manual * Revision J * Issued November 2005 * Ref. 185041340 (185041713 internal) | 19 |