Siemens LMV5 Series Basic Documentation

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Siemens Building Technologies Basic Documentation LMV51... CC1P7550en
HVAC Products 4 Burner control 01.10.2003
When gas pressure is insufficient (input PSmin-gas), the LMV5... ensures that a
selectable number of start attempts will be made while observing a selectable waiting
time.
The waiting time between the start attempts is automatically doubled (based on the
value parameterized for the first waiting time).
The basic time is «DelayLackGas».
Parameter: DelayLackGas
If, with the last of the parameterized start attempts, there is still a shortage of gas, the
burner control will initiate lockout.
Parameter: StartPrev
Phase
PSmin-Gas
12
Standby
1. tDelay_G
10 s
12
Standby
21
10
tmax2
(e.g. 60 s)
Test repetition counter
< n
Home run
21
10
tmax2
Test repetition counter
< n
Home run
2. tDelay_G
10 s x 2
1
= 20 s
8. tDelay_G
12
Standby
21
10
tmax2
Test repetition counter
< n
Home run
9. tDelay_G 12
Standby
21 01
tmax2
Test repetition counter
= n = 10
Safety phase
Alarm
00
7550f22E/0502
Start conditions must be satisfied.
n = Limitation of the number of start repetitions
(StartPrev). Example: 10
tDelay_G = Delay time gas shortage program
(DelayLackGas). Example: 10 s
Signal «OFF»
Signal «ON»
- Repetition counter will be reset after controlled shutdown
- When phase 22 is reached for the first time, delay time
will be reset to the selected parameter value
10 s x 2
7
= 1280 s
10 s x 2
8
= 2560 s
To prevent the boiler from shutting down when operating at high-fire, FARC will first
change to low-fire when there is no more demand from the controller.
Only then will the valves be closed.
The maximum time «MaxTmeLowFire» for changing to low-fire operation can be
parameterized.
If the time is set to 0.2 seconds, part load shutdown will be deactivated.
Parameter: MaxTmeLowFire
Gas shortage program
Sequence diagram
Part load shutdown

Siemens LMV5 Series Specifications

General

Brand	Siemens
Model	LMV5 Series
Category	Control Systems
Language	English