Other Malfunctions; Leakage Faults; Flow Faults (With Zero-Gas And Test-Gas Flow) - Bosch ETT 008.31 Repair Instructions

7.4

Other malfunctions

Malfunction
Control-panel keys defective,
appropriate LED does not light
up.
Pump does not start up.
Function switch S 60
appears defective.
Main switch appears defective.
8 Trouble-shooting
8.1

Leakage faults

(Also see gas-route diagram in Section 12.3)
In the course of leak testing, if an error message appears as a result of insufficient tightness, this means that the gas pump is sucking
up unclean outside air and the test gas in the receiving chambers is being diluted.
Check: Is the fine filter correctly fitted?
Is the condensation tank correctly mounted?
Remedy existing faults and perform leak test again.
If leakage is still present, open the analyzer.
For trouble-shooting, carry out further leak tests to determine whether:
- the solenoid valve is letting in unwanted air through the blocked-off zero-gas duct
- the blocked-off test-gas duct (condensation tank, hose 4, fine filter and safety filter or hose 6) is leaky
- hose 9 to the gas pump or the gas pump itself is leaky.
- To remedy:
- if during further leak tests the sealing prompt "Abd.
- in the next seal test hose 6
- then hose 9 or - if the test still produces incorrect results - seal hose 16 as well (the pump could also be leaky and suck up outside
air!)
Replace faulty components
8.2

Flow faults (with zero-gas and test-gas flow)

The error message "Flow fault during zero adjustment" or "Flow fault in test-gas line" occurs when one of the pressure switches
DS 1 or DS 2 is defective or detects inadequate pressure.
Also see gas-route diagram in Section 12.3.
. One gas pump sucks up zero gas via the solenoid valve MV 1 during zero adjustment, and test gas via hose 6 during measurement.
In the upper safety tank, pressure builds up which is monitored by pressure switch DS 1 via hose 17.
. The second pump sucks up test gas and condensation via hose 7. The restrictor ∅ 1.7 causes pressure to build up in the lower safety
tank, and this is monitored by pressure switch DS 2.
Both pumps always run together. During zero adjustment, only the results from pressure switch DS 1 are retrieved. If analysis then
follows (MV 1 has switched to the test-gas inlet), the results from both pressure switches are retrieved. Thus, if the error message
"Flow fault in test-gas line" appears, then the fault may have occurred in either of the pressure switches.
Check: to Section 8.2.1, whether an obstruction (clogging with dirt) is preventing the build-up of pressure in the test-gas
to Section 8.2.2, whether a pressure switch is defective
to Section 8.2.3, wether leakiness after the pumps is preventing the build-up of pressure, or
to Section 8.2.4, whether a pump is defective (unsatisfactory delivery rate).
34
Trouble-shooting to Section:
8.3 "Indicating faults" or replace display module.
8.14 "Faulty pump actuation"
8.15 "Checking the sensor-board"
8.17"Power supply to motherboard", check in accor-
dance with circuit diagram, Sections 12.1 and 12.2.
Abd." appears on the display, seal hose 8 with a hose clamp Abd. Abd. Abd.
or zero-gas lines