Viessmann MatriX Service Instructions Manual page 39

Gas burner control unit flow chart
After the controller issues a heat demand, the following program sequence
will be run:
Phase
01 Test for heat demand
02 Idle state check of the air pressure limiter
and the fan
03 Fan ramp up
(a fault shutdown will be initiated if the air pressure limiter
does not signal that the air pressure has reached
a specified range within this timescale, or
the fan does not reach its set speed)
04 Pre−purge I
05 Pre−purge II
06 Pre−purge III
07 Ignition
(if the fan speed does not achieve the set value,
the gas burner control unit will display a fault)
08 Pre−ignition
09 Start−up safety period (safety period A)
(safety valves enabled at the beginning of
safety period A, safety period operation < 1 s)
10 Stabilising the flame in the ignition position
187 kW:
248 and 314 kW:
11 Changeover to control operation
(up to the programmed set speed)
12 Operation
(the system will be restarted after expiry of this time)
13 Burner run−on time
17 Post−purge
18 Restart lockout time
19 Gas shortage position
20 Standby
(a restart follows a heat demand and the system will be
restarted after expiry of this time)
in case of fault shutdown from phase 09:
21 Fan run−on prior to lockout
Gas burner control unit flow chart
(cont.)
Duration
1 s
1 to 30 s
1 to 30 s
5 s
1 s
30 s
1 to 30 s
2 s
2.8 s
20 s
55 s
1 to 30 s
max. 23:59 h
max. 30 s
1 to 60 s
0 s
max. 30 min
max. 23:59 h
5 s
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