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5.2. Troubleshooting
5.2.1. Low Temperature
Condition detected Possible cause Action to take
desired, no alarm.
Airway temperature low
alarm activated.
Temperature probe not in position.
Check position of temperature probe in the
circuit.
Gas flow stopped or interrupted.
Turn humidifier off until gas flow resumed.
Temperature probe not in probe housing.
Increase gas flow to more than 5 liters per
minute.
Chamber temperature
low alarm activated.
Too much distance between end of heater wire
and temperature probe.
Use longer heater wire or shorten
inspiratory hose so that distance is
between 25 (1”) and 100 mm (4”),
ideally 30mm.
Poor thermal contact between base of chamber
and heater plate.
Check that chamber base and heater plate
are clean, smooth and flat.
If necessary clean or replace.
Temperature probe not inserted at chamber
outlet.
Fit temperature probe correctly.
Heater element needs replacement.
5.2.2. High Temperature
high alarm
activated.
Sudden spurious increase in gas flow.
Wait for temperature to fall below
threshold.
Heater wire too close to temperature probe.
Use shorter heater wire or lengthen
inspiratory hose so that distance is between
25 (1”) and 100 mm (4”), ideally 30 mm.
Possibly faulty Airway sensor on temperature
probe (low resistance).
high alarm activated.
Refill humidification chamber.
Possibly faulty Chamber sensor on temperature
probe (low resistance).
5.2.3. Temperature Fluctuating
Condition detected Possible cause Action to take
temperature alarms.
Ventilation rate too low or too erratic for proper
humidifier temperature control.
Ventilation rates below about 6 bpm or of
highly erratic nature may affect the
stability of the temperature control.
Humidifier temperature control influenced by
external heating or cooling such as air
conditioner.
Shield breathing circuit from external
influence.
Temperature probes incorrectly positioned.
Check temperature probe position in the
circuit.
Possibly faulty temperature probe
(Could be intermittent short or open circuit)
(Wriggle probe to pick up intermittent