Datex-Ohmeda 7900 - Page 87

4/Tests and Troubleshooting
1503-0151-000 5/26/0 4-41
Alarm
Message/Symptom
Condition/Probable Cause Service Action
Inspiratory flow sensor
Fail
Expiratory flow sensor Fail
EEPROM cal data read failure
(using default cal data
Remove flow sensor from breath-
ing circuit.
Disconnect from patient interface
panel and reconnect sensor. If
error message goes away, sensor
OK. If error message reappears,
replace bad flow sensor
Insp. V
T
/V
TE
volume Mis-
match
V
TE greater than
V
TI
(Circle) or
V
TI
greater than V delivered
(Bain or Circle)
1. Check system tubing for leak-
age. Refer to Pressure Sensitivity
CAL Fail in Section 4.
2. Check the flow sensor
3. Replace the flow sensor
1. No Insp Flow Sensor
2. No Exp Flow Sensor
3. Inspiratory Reverse
Flow
4. Expiratory Reverse Flow
5. Check Flow Sensors
1. No inspiratory flow sensor
connected
2. No expiratory flow sensor con-
nected
3. Negative flow on inspiratory
flow sensor during inspiration
4. Negative flow on expiratory
flow sensor
5. Incorrect connection, 0 flow on
Insp sensor during inspiration, or
0 flow on Exp sensor in expira-
tion after seeing flow in inspira-
tion
1. Examine check valves, free
breathing valve and MOBO
2. Check flow sensor locations
and tubing connections
3. Check breathing circuit configu-
ration
O
2
calibration error O
2
not equal to set O
2
f± 1%
O
2
greater than 110%
Calibrate O
2
sensor
On Battery Status line indicates "on battery",
or battery current test greater
than 300 mA
1. Is AC LED off?
2. Check system power cord and
fuses
3. Check AC wall power, if o.k
replace battery - replace CPU
Be aware of a 30 min. max. of
batt. operation
Sans Gas Frais Patient breathing in DCGO Operator has attempted to turn on
the ventilator with the dual com-
mon gas outlet in the auxiliary
position
A/D Converter Failure
Minimum System Shut-
down
ADC time out, monitoring is not
functioning or it is unreliable
Reboot ventilator, if problem con-
tinues replace CPU board
Bootup Memory Failure
Minimum System Shut-
down
Bootup memory CRC failure,
monitoring is not functioning or it
is unreliable
Reboot ventilator, if problem con-
tinues replace CPU board