Viessmann VITODENS 200-W WB2B Series Start-Up/Service Instructions page 25

Steps
(continued)
I S
nitial start-up ervice
26. Clock natural gas meter
Clock natural gas meter to verify input.
Ensure all other gas equipment
1.
served by the meter is turned off
during timing of gas input to the
Vitodens 200-W, WB2B boiler.
2.Measure the time in seconds it takes
for the boiler to use 10 ft.
Divide 3600 x 10 by the number of
seconds and you get the number of
3
ft. of gas used per hour. Multiply
this number by the heating value of
the gas to obtain Btu per hour input.
Initial Start-up and Service
For example:
A Vitodens 200-W, WB2B 9-26
boiler (93 000 Btu/h input) requires
387 sec. to use 10 ft.
gas. After contacting the local utility,
you will find the heating value is
3
of gas.
1000 Btu per ft.
Therefore,
3,600 sec./h x 10 revolutions
36,000/387 x 1000
input. The boiler input is correct.
Burner input formulas
(for low altitude only):
INPUT=(3600
t=TIME (sec.) for 1 ft.
INPUT=(3600 x .01 x 1000 x
÷
35.31) T where
T = TIME (sec.) for .01 m
gas
IMPORTANT
A boiler underfired by 5% is
acceptable. Do not overfire the boiler.
CAUTION
Always contact your gas utility to
obtain the correct heating value before
clocking the meter.
3
of natural
3
.
≅
93,000 Btu/h
÷
t) x 1000 where
3
3
natural
25