Safety Notes; Warning Notes - Siemens QGO21 Series Basic Documentation

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Building Technologies Division
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Safety notes

1.1 Warning notes

To avoid injury to persons, damage to property or the environment, the following
warning notes must be observed!
It is not permitted to open the sensor incorrectly, interfere with or make changes
to the sensor!

All activities (mounting, installation, service, etc.) must be performed by qualified
staff

Before making any wiring changes in the connection area, completely isolate the
plant from mains supply (all-polar disconnection). Ensure that the plant cannot be
inadvertently switched on again and that it is indeed dead. If not observed, there is
a risk of electric shock hazard

Ensure protection against electric shock hazard by providing adequate protection
for the connection terminals

During operation, the sensor's connecting head must be kept closed; all 3 screws
must be securely tightened

Each time work has been carried out (mounting, installation, service work, etc.);
check to ensure that wiring of connected lines is in an orderly state and make the
safety checks as described in Commissioning notes. Keep cables away from
extremely hot plant equipment or sensor parts

During burner operation, QGO21 must be kept on operating temperature via
associated control unit (LMV52 with PLL52)

Always keep the sinter filter free from dirt, this extended the response time of the
sensor

The maintenance timer of LMV52 must be used to ensure that the maintenance
interval is complied with (see LMV52 User Documentation A7552)

All setting instructions of the LMV52... must be observed (see User Documentation
A7552, chapter O2 control). In particular, we wish to draw your attention to the
manipulated variable limitation that is described there.

The environment must be free from chemicals such as vapors from solvents

Before cleaning the sinter filter, allow the QGO21 to cool down for at least 1 hour.
When using compressed air for cooling (only after the sensor has completely
cooled down), pressures up to 0.5 bar are permitted. If this is not observed, the
sensor can be damaged in a way that inadmissibly high CO levels in the flue gases
can occur
Caution - risk of explosion!
Check that the sintered filter is seated correctly, has been screwed tightly in
place, and inspect the sensor for damage.
If sensors are damaged or not tightly fitted, or if sintered filters are not present,
this may lead to the loss of the flame arrester.
Warning!
The QGO21 must be maintained regularly.
The OEM and the heating engineer are obliged to:

set a maintenance interval suitable for the system and

to carry out the maintenance outlined in the QGO21 Basic Documentation
(P7845), chapter Maintenance instructions.

Fall or shock can adversely affect the safety functions and lead to dangerous
conditions. Such sensors must not be put into operation, even if the measuring cell
does not exhibit any damage

Ensure that air cannot enter the space between burner and measuring parts. In
particular, the mounting flange must be completely gas-tight
Oxygen Sensor QGO21...
1 Safety notes
CC1P7845en
06.12.2017