Datex-Ohmeda Aestiva 7900 SmartVent, Service Manual

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4/Tests and Troubleshooting
4-12 1503-0151-000 5/26/0
Test Gas Inlet Valve (GIV)
To test the gas inlet valve the software first closes the GIV. It then reads the A/D
for the GIV. If the A/D for the GIV does not read closed, the test fails. The software
then opens the flow valve to the calibrated flow of the bleed resistor. Then it waits
for the flow to stabilize (about 2 seconds). Once the flow is stabilized the software
checks to see if manifold pressure has dropped to less then 0.5 cmH
2
O. If manifold
pressure does not drop below 0.5 cmH
2
O, the test fails. The software then closes
the flow valve and opens the GIV. It then reads the A/D for the GIV and if the A/D
for the GIV does not read open, the test fails.
Gas Inlet Valve FAIL Instructions:
Failure can be caused by the valve malfunctioning or the microcontroller board.
Use a multimeter to measure the resistance of the GIV solenoid. It should be ap-
proximately 25 ohms. If necessary, replace the GIV solenoid.
Use a multimeter to measure the voltage at the inlet valve connector which plugs
into the microcontroller board. The voltage should be 4.5 volts when the GIV is
open. If the voltage is 4.5 volts or greater, rebuild the GIV. If the voltage is less
than 4.5 volts replace the microcontroller board.