How The Vitodens 100-W Boiler Operates - Viessmann VITODENS 100-W WB1B Series Installation And Service Instructions Manual

Steps
(continued)
Start-up and Maintenance
Start-up and Maintenance
Fig. 49
Legend
A Inlet gas pressure measurement
port
B Outlet pressure port
C Low-fire adjustment screw / cover
D Hi-fire adjustment screw
Initial Start-up, Inspection and Maintenance

5. How the Vitodens 100-W boiler operates...

The Vitodens 100-W boiler uses a premix combustion system, which is
designed to deliver a measured air-gas mixture to the burner for complete
combustion. The gas is injected upstream of the blower. The burner and
heat exchanger are part of a forced-draft design. The benefits of forced-draft
systems are lower component temperatures, direct air-fuel connection (premix)
for improved mixing, and longer service life of the boiler due to mild
to moderate ambient conditions.
The matrix cylinder burner blower and the combination gas valve are factory
calibrated and pre-adjusted for optimum boiler performance at all firing rates
through a pneumatic link between combustion air and gas flows. Blower
speed is automatically increased or decreased based on heat demand, thereby
regulating the amount of combustion air drawn. The pneumatic link between
air and gas introduces the required amount of gas for correct combustion to
meet the current heat demand, based on a linear relationship between ∆ P air
and ∆ P gas.
49