Fresenius Medical Care 5008, Service Manual

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Chapter 4: Installation
4-16 Fresenius Medical Care 5008 SM 1/08.04
Basic requirements:
– Measurement of the protective earth resistance performed.
– Perform the measurement with the hemodialysis system being at operating temperature.
– Dialysate:
Dialysis temperature:
≥
37 °C
Dialysate flow:
≥
300 ml/min
Conductivity:
≥
13 mS/cm
– When performing a direct measurement, the following precautions also must be observed:
The system must be insulated when installed.
All external connections must have been removed from the system.
The line voltage during the measurement will be recorded, as well as the maximum device leakage
current of both mains polarities, scaled to the nominal voltage of the power supply. Maximum device
leakage current: 500
µ A
Example:
Line voltage during the measurement: 225 V
Device leakage current
for mains polarity 1: 180
µ A
for mains polarity 2: 120 µ A
Maximum value of both mains polarities: 180 µ A
Nominal voltage of power supply: 230 V
Scaled to nominal voltage: 184
µ A
(180 µ A: 225 V x 230 V = 184 µ A
Device leakage current < 500 µ A: OK
Additional requirements:
If the device leakage current, scaled to the nominal voltage, is higher than 90 % of the admissible alarm
limit (450
µ A), the last measured value or the first measured value must additionally be considered for
the rating.
If the device leakage current has considerably increased since the last measurement or has continuously
increased since the first measurement (creeping deterioration of the insulation), or if the sum composed
of the current value plus the difference since the last measurement is >500
µ A, the measurement has
not been completed successfully.
Example 1:
Device leakage current: 470
µ A
Last measured value: 450 µ A
470 + (470 – 450) = 470 + 20 = 490; is OK
Example 2:
Device leakage current: 470
µ A
Last measured value: 390 µ A
470 + (470 – 390) = 470 + 80 = 550; not passed
10 Check – zero point arterial/venous pressure display and venous clamp
10.1 Zero point arterial pressure display
Basic requirements:
Blood lines inserted, pressure domes coupled, standby operation.
Check the arterial pressure display.
Desired value: –5 mmHg to +5 mmHg
No. Description