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Building Technologies Division
Basic documentation LMV36...
CC1P7544en
Infrastructure & Citiies Sector
1 Safety notes
25.09.2013
The functions of the following available or required input status signals must be
checked:
Air
pressure
Minimum gas pressure / maximum gas pressure or POC
Gas pressure valve proving
Minimum oil pressure and maximum oil pressure
Safety loop (e.g. safety limiter)
Duties of the expert when making the approval tests
Action
Check / response
a)
Burner startup with flame detector
darkened
Lockout at the end of safety time 1 (TSA1)
b)
Burner startup with flame detector exposed to
extraneous light, e.g. to incandescent light with
detectors for visible radiation, quartz-halogen bulb
or cigarette lighter flame with detectors for UV
radiation
Lockout at prepurge time (t1)
c)
Simulation of loss of flame during operation. For
that, darken the flame detector in the operating
position and maintain that state
Lockout or restart, depending on the basic unit’s
configuration
d)
Check the plant’s response time with loss of flame
during operation. For that purpose, manually
disconnect the fuel valves from power and check
the time from this moment the basic unit requires to
turn off power to the valve
Turning off power to the valves by the basic unit within
the period of time permitted for the respective type of
plant
e)
Check the safe operation of the burner while giving
consideration to system tolerances
System tolerances are the result of a number of factors,
such as:
-
Tolerances of actuators plus mechanical linkage to
the controlling elements
-
Environmental
conditions
(temperature, air conditions)
-
Type of fuel (calorific value / pressure)
-
Type of supply air path and flue ways
Example of procedure for checking the burner’s
response to actuator tolerances:
-
Approach a output point in programming mode (e.g.
low-fire or high-fire)
-
Change the actuator’s position against the optimum
fuel-air ratio setting as can be expected in the case
of tolerances
-
Check the flue gas values with a flue gas analyzer
Recommendation:
Make this readjustment against the optimum fuel-air
ratio setting for one actuator at a time!
Further checks may be required, depending on the field of use and the relevant
standards.