Viessmann MPA51 Operating And Service Instructions page 25

Flow diagram
(cont.)
After the controller issues a heat
demand, the following program
sequence will be run:
Phase
00 Fault
01 Waiting for heat demand
03 Fan idle state check
04 Air pressure switch idle state check
06 Fan ramp-up
07 Waiting for air pressure
08 VPS decision: Valve tightness check
09 VPS: Clear intermediate valve space
10 VPS test time: Valve 1
11 VPS: Fill intermediate valve space
12 VPS detection: Gas pressure
13 VPS test time: Valve 2
14 Pre-purge time
16 Ignition setting
17 Gas detection: Gas pressure switch min.
18 Pre-ignition time
19 Ignition safety time (SZA)
20 SZA flame recognition
21 Flame stabilising time
23 Changing to control mode
24 Control mode
25 Changing to controlled shutdown
32 Burner run-on time
33 Post-purge time
34 Restart blocking time
01 Waiting for heat demand
In the case of fault shutdown:
35 Gas shortage: Gas pressure switch min.
36 On hold program
Flow diagram
Duration
0 ...
0 ...
max. 2 min
max. 5 s
max. 2 min
max. 5 s
0.1 s
1 to 3 s
1 to 240 s
1 to 3 s
0.1 s
1 to 240 s
0 to 1 h
max. 2 min
0 ...
0 to 1 min
0.5 to 9.4 s
0.5 s
1 to 200 s
max. 2 min
0 ...
1 to 30 s
1 to 60 s
0 to 1 h
0 to 1 h
0 ...
0 ...
0 ...
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