Viessmann MatriX radiant burner Service Instructions Manual page 22

Initial start−up, inspection and maintenance
Gas burner control unit
Service display
The service display can only be shown with the burner in operation, i.e. a
heat demand from the control unit must be present.
During the service display, the burner will not respond to output changes
from the control unit (regular stop mode).
Operating display
Status Service
Operating display
22
(cont.)
Activate the service display by simultaneously
pressing keys b and S
Control stop mode
Under Service, the display shows the current level
of modulation in %.
For this: 00 = 0 % = partial load
For this: and
For this: 00. (with decimal point after last figure)
For this: = 100 % = Full load
Reducing the modulation level
Increasing the modulation level
Simultaneously press keys b and S