Datex-Ohmeda CAPNOMAC ULTIMA, Service Manual

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CAPNOMAC ULTIMA™ SERVICE MANUAL
7-5
O
2
measurement flow pressure measurement
Gradual decrease of main flow rate due to the water trap filter
clogging can be checked by measuring pressure difference between
the O
2
measurement flow and the O
2
reference flow. Remember
that the sampling line should be attached to the water trap during
test.
The pressure difference is automatically checked after every gas
zeroing.
The pressure difference can be manually calculated as follows:
Enter GAS SERVICE in the Service Mode
a )
Set pump on, both valves closed (this is the normal
operation situation). Check the PRE value. It is the
pressure of the O
2
sensor measurement flow.
b)
Press the 2 key to open the pressure valve. Now the
PRE value shows the pressure of the reference flow.
c )
Subtract the value gained in step 2 from the value
gained in step 1 and you will have the pressure
difference between the O
2
measurement flow and the O
2
reference flow.
The pressure difference should be between 5 to 10 mmHg (factory
adjusted).
If the pressure difference is too large, decrease the measurement
flow rate by changing the cassette no. 21.
When the pressure difference becomes negative, that is, the
pressure in the reference flow gets higher than that of the
measurement flow, and reaches -5 mmHg, then during normal
monitoring the message “REPLACE TRAP” appears and the
audible alarm sounds to indicate that the water trap should be
replaced.
January 15th, 1997/6