55/213
Building Technologies Basic documentation LMV37.4... CC1P7546en
HVAC Products 6 Basic unit 01.12.2009
6.5.3.5. Start without prepurging (as per EN 676)
When using valve proving and 2 fuel valves of class A, prepurging is not required (con-
forming to EN 676).
Prepurging can be deactivated per parameter.
No. Parameter
222
Gas: Prepurging
0 = deactivated
1 = activated
When prepurging is activated, it is performed in accordance with the adjusted prepurge
time.
If not activated, it is nevertheless performed if one or several of the following conditions
apply:
• Alterable lockout position
• After an off time of >24 hours
• In the event of a power failure (power-on)
• In the event of shutdown due to an interruption of gas supply (safety shutdown)
No. Parameter
225 Gas: Prepurge time
6.5.3.6. Gas shortage program
Valve proving via pressure switch-min-gas (P236 = 2)
As gas pressure switch-min-gas is located between the valves, the gas shortage test
cannot be made in phase 22. Instead, when performing valve proving on startup, the
gas shortage test is performed at the end of the filling time (end of phase 82). Without
valve proving on startup, the gas shortage test is made directly before safety time 1
commences (end of phase 39).
Standard valve proving (P236 = 1)
If the gas pressure is too low, startup is aborted in phase 22.
No. Parameter
246 Gas: Gas shortage waiting time
If gas shortage occurs with the last of the parameterized number of start attempts, the
system initiates lockout.
No. Parameter
223
Repetition limit pressure switch-min-gas
1 = no repetition
2...15 = number of repetitions
16 = constant repetition
In that case, the system with gas shortage program makes a selectable number of start
attempts until lockout occurs. The waiting time from one start attempt to the next is dou-
bled each time, starting from a waiting time that can be parameterized.
To Next Page
Loading...
