Siemens LMV 5 Series, Technical Instructions, Page: 144 / 374

Technical Instructions LMV Series
Document No. LV5 ‐ 1000
Section 4 Page 26 SCC Inc.
d. Temperature / Time ‐ based Stepping Start Combination
This method combines methods b and c and if set correctly, is the fastest way to safely
warm the boiler. The settings are similar to method b , but now parameter
MaxTmeMod is set to have an effect (10 minutes for example). When this is done, the
maximum time that a step ‐ up in load will take is 10 minutes, regardless of the
temperature change. If the temperature change defined by StageSetp_Mod happens
before the 10 minutes elapses, then the temperature change will trigger the step ‐ up in
load.
When this mode is used, time usually triggers the load steps at the start of boiler
warming and temperature change usually triggers the load steps closer to the
ThresholdOff temperature. This is due to the more rapid rise in boiler temperature at
higher firing rates.
5.
After parameters are set for one of the methods above, set parameter ColdStartOn to activated.
The next time the burner is started and the water temperature is below the ThresholdOn
temperature, cold start should engage.
Below are typical settings for each of the four ways cold start can be set up.
Example: Steam Boiler with an Additional Temperature Sensor
Parameter Low Fire Hold Temp ‐ based Time ‐ based Temp/time ‐ based
ColdStartOn Activated
ThresholdOn 50% (= 150°F)
StageLoad 0% 5% 5% 5%
StageSetp_Mod N/A 5% 100% 10%
StageSetp_Stage Staged Operation Only
MaxTmeMod N/A 63 min 5 min 10 min
MaxTmeStage Staged Operation Only
ThresholdOff 80% (= 240°F)
AdditionalSens Pt1000
Temp. ColdStart Read Only
Setp AddSensor 300°F
Release Stages Staged Operation Only
Figure 4 ‐ 8: Typical Cold Start Parameter Settings
The following page shows an example of a time ‐ based stepping start.
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