Oxygen Supply Pressure Alarm Switch (Earlier Machines) - Dräger Narkomed 2B Service Manual

NM2B
4.8

Oxygen Supply Pressure Alarm Switch (earlier machines)

The oxygen supply pressure alarm switch is located behind the gas
instrumentation panel. Access to the switch requires removal of the flowmeter
housing rear cover. The replacement switch must be tested to ensure that its
operating point is set correctly. Figure 4-8 shows the switch assembly on
earlier machines where the switch is supported by the O
On later machines with flowmeter assemblies having an Oxygen Ratio
Controller (ORC), the oxygen supply pressure alarm switch is part of the alarm
channel assembly. Refer to the procedure titled "Alarm Channel and Oxygen
Supply Pressure Alarm Switch" for specific replacement instructions.
4.8.1
4.8.2
4.8.3
4.8.4
4.8.5
4.8.6
4.8.7
4.8.8
4.8.9
4.8.10
4.8.11
4.8.12
4.8.13
4.8.14
Rev. A
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REPLACEMENT PROCEDURES (continued)
Disconnect all pipeline hoses and set the System Power switch to ON.
Close all cylinder valves except the O
Set the oxygen flow to 5 liters per min.
Open the other gas flow control valves to drain pressure from the
system.
Close the O cylinder valve and the O
2
O Flush valve to drain oxygen pressure from the system.
2
Set the System Power switch to STANDBY.
Remove the screws holding the rear cover, and remove the cover.
Disconnect the two compression fittings at the TEE.
Note the position of the wires on the switch so that the replacement
unit can be connected in the same manner. Disconnect the wires from
the switch and remove the assembly.
Connect the wires to the replacement assembly; connect and tighten
the compression fittings on the O
Remove the screws holding the table top to the machine and lift out
the table top.
Pull the writing or keyboard tray out to its fully extended position.
Locate the TEE fitting in the ¼ in. diameter output line of the O
regulator and remove the plug from the TEE fitting.
Connect a dedicated O
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valve.
2
flow control valve. Press the
2
lines.
2
test gauge to the TEE fitting.
2
tubing.
2
2