12
3 Technical description
3.3.4 Program sequence
The burner operating phases are shown on the display, as following:
Phase
Function
TEST
After the power supply is switched on, the combustion manager performs a self-test.
G L
At call for heat, the air and gas stepping motors drive to the reference position.
1
The combustion manager monitors for extraneous light or flame.
2
The air damper stepping motor drives to pre-purge (operating point
P9
). The gas butterfly stepping
motor drives to ignition position (operating point
P0
).
3
The pre-purge is started. The air pressure switch is checked and must be closed.
4
Pre-purge. The remaining pre-purge time is displayed.
5
The air damper stepping motor drives to ignition position (operating point
P0
).
6
Gas valve V1 opens. The low gas pressure switch is checked and must be closed. Ignition spark starts.
7
Gas valve V2 opens. The gas is released. The safety time begins. The display shows the symbol
8
Flame stabilization. The high gas pressure switch is checked and must be closed.
9
The air damper and gas butterfly valve stepping motors drive to low fire.
10
The burner is in operation. Ready for modulation.
11
...
14
Valves proving sequence is activated - optional, for special applications.
15
Following the post-purge, the burner motor is turned off. The air damper and gas butterfly valve are closed.
OFF
Stand-by, no call for heat.
Installation and Operating Instructions
Gas burner WG20.../1-C ZM-LN (W-FM 25)
83055116 • 1/2016-05