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Siemens Building Technologies Basic Documentation LMU54... / LMU64... CC1P7494en
HVAC Products 3 Functions 07.11.2002
3 Functions
3.1 Burner control
Parameterization enables certain parts of the burner control program to be changed,
thus permitting a number of different burner control sequences.
The burner control sequences are distinguished by their capacity ranges in which the
boilers shall operate.
In accordance with the standards, there are 3 different capacity ranges:
• < 70 kW
• 70...120 kW
• > 120 kW
For all capacity ranges, there are additional parameterization choices available,
enabling the burner control’s sequence and times to be matched to specific
requirements.
The EEPROM of the LMU... is used to store the burner control’s program sequence and
lockout positions.
Also, control parameters and other setting values are filed in EEPROM.
Forced intermittent operation ensures that the burner control initiates shutdown after no
more than 24 hours of continuous operation.
This enables the burner control to perform the internal self-tests included in the startup
and shutdown sequence.
The burner control’s program ensures orderly operation of the unit including startup and
shutdown as well as flame supervision.
The sequence can be altered by changing certain parameters.
If there are deviations from the defined sequence, or in the case of a reset, the program
initiates safety shutdown (home run) and then - depending on the setting made -
lockout, restart or start prevention.
The program sequence is controlled in accordance with the program’s phases. The
individual phases are grouped and include startup, operation, shutdown and home run.
After a reset (power on), the burner starts its home run. Depending on the available
(parameterized) input / output signals or program times (e.g. prepurging), the individual
program phases will be either executed or skipped.
The burner control’s program is designed for intermittent operation. To verify orderly
functioning (detection of faults), a complete program cycle is required.
In the «Standby» position, the burner control is ready to operate and waits for a heat
demand signal from the controller, or it demands start prevention (no release).
The burner control maintains the «Operation» position until no more heat is demanded
by the controller - but for no more than 24 hours. On completion of that period of time,
the burner control will automatically enforce intermittent operation.
Program selection
EEPROM
Forced intermittent
operation
Burner control program
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