- 7 -
4.0 Control Layout and Functioning
The starting point for how the control will act in the various situations depends on the actual plant
temperature, compared with the chosen running temperature. The KSM oxygen control will automatically
adjust the output between full load and 30% load. If the heat consumption drops beneath 30% of full load,
the control will make a pause and start up the plant again when heat is required.
Out of regard for the boiler life, and the upholding of the guarantee, the running temperature should
always be kept at minimum 70
o
C, this temperature is also called the ”set-point” which is the designation
used in the below explanation.
4.1 Opstart.
OPSTART
O
2
: 12%
TEMP 50°C PRG 1
If the plant has stopped due to too high oxygen (lack of fuel or the fire has extinguished for some other
reason) and the display therefore indicates ALARM, press the OPSTART button to re-start the plant. The
display will state the word OPSTART indicating that the plant is in the starting-up mode.
The fan will now pulse i.e. it will blow quite gently. When the fuel has caught fire and the oxygen has
dropped below oxygen limit value (please see section 6.30) - oxygen difference (please see section 6.28),
the control will go into operation.
However, if the starting-up procedure does not succeed sufficiently before the Start-up time has run out
(please see section 6.27), the plant will stop and the display will state ALARM. And it is necessary to
start up the fire again.
4.2 ALARM
ALARM O
2
: 18%
TEMP 30°C PRG 1
If the plant has run for more than 3 minutes with an oxygen percentage higher than Oxygen limit value
(please see section 6.30), the plant will switch into to starting-up mode and try to re-light the fire; and if it
does not succeed to do, so before the start-up time has run out (please see section 16.27), the plant will
stop and the display will state ALARM.
4.3 Steps.
STEP 0 - 3
O2: 12%
TEMP 70°C PRG 1
During normal running, the stoker operates at varying output and the display will indicate the applied
steps. This means that the control adapts the output to the consumption from the heating plant. However,
the control will switch the plant into the pause mode if the consumption drops to less than 25% of full
load. Or in other words, if the temperature rises to more than 5
o
C above the set-point, the plant will
switch to step 0, but if that is not sufficient and the temperature rises to 10
o
C above the set-point, the
control will switch to pause.
The combustion air fan runs in 4 steps, see the following description.
Step 3: The temperature is more than 6°C under the set-point.
The combustion air fan runs constantly.
Step 2: In the interval from 5°C under the set and up to 1°C over the set-point, the combustion air fan
runs at step 2. - The combustion air fan pulses, with a long blow and a short break.
