Function Test; Visual Inspection; Checking The External Gas Duct; Checking The Protective Earth - Bosch ETT 008.31 Repair Instructions

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Function test

5.1 Visual inspection (device is switched off and disconnected from mains)
- Check safety seal on rear wall of housing:
If used in countries with compulsory calibration, the device must be calibrated again if the seal is damaged.
- Check that power cord is in perfect condition, replace if damaged.
- Check that mains jack and female connectors for the clamp-on speed sensor and oil-temperature sensor are secure.
Check that interface connector is secure.
- Check that carry handles on the housing are secure and mechanically safe:
If the handle can be moved in the housing, one of its fastening pins may be broken.
Check the handle fastening from inside for breaks and replace handle if necessary.
5.2

Checking the external gas duct

Exhaust-sample probe
Detach from the hose and blow out with compressed air against the intake direction. Clean encrusted solid dirt from the tip of the probe.
Exhaust-sample intake hose
Remove from the exhaust-gas analyzer, remove coarse filter GF 1 from the hose. Check hose for cracks or other leakage points and
replace if necessary. Blow out intake hose with compressed air.
Replace coarse filter GF 1 if clearly clogged, and re-assemble intake hose, coarse filter and probe.
Condensation tank
Remove carefully. Check edge of condensation tank for cracks, replace if damaged.
Replace coarse filter GF 2 in the condensation tank if seriously clogged.
! Push the coarse filter into the connecting hose as far as the connecting piece which adjoins the head.
Connect condensation tank and check:
The bottom end of the coarse filter must still be 2 to 4 mm from the floor of the condensation tank.
Re-connect the intake hose to the gas inlet.
Fine filter paper
Check and replace filter paper if seriously discoloured grey or if wet. To do so, remove filter cover by turning anti-clockwise. Change
filter paper. The filter paper must lie completely inside the cover (press with the flat of your hand).
Check:
The sealing edge in the filter housing must be absolutely clean (no remains of old paper filter!).
The sealing ring in the filter housing must be undamaged and clean. Screw in the filter cover.
5.3

Checking the protective earth

Remove the mains connector, switch on the mains switch of the specimen device.
Check protective conductor contacts of mains connector to housing:
Check mains connector and contacts L and N to protective conductor: R > 10 MΩ
R < 1Ω
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