Clock Natural Gas Meter - Viessmann VITODENS 100-W WB1B Series Installation And Service Instructions Manual

Steps
(continued)
Start-up and Maintenance
Start-up and Maintenance
Initial Start-up, Inspection and Maintenance

8. Clock natural gas meter

Clock natural gas meter to verify input
1. Ensure all other gas equipment
served by the meter is turned
off during timing of gas input to
the Vitodens 100-W boiler.
2. Measure the time in seconds it
takes for the boiler to use 10 cu.
ft. of gas. Divide 3600 x 10
by the number of seconds and you
get the number of cu. ft. of gas
used per hour. Multiply this
number by the heating value of
the gas to obtain Btu per hour
input.
For example:
A Vitodens 100-W boiler
(118 000 Btu/h input) requires 305
seconds to use 10 cu. ft. of natural
gas. After contacting the local utility,
you find the heating value is e.g.
1000 Btu per cu. ft.
Therefore,
((3600 x 10)/305) x 1000
118 000 Btu/h input.
Therefore, the boiler input is correct.
Burner input formulas
(up to 4500 ft.):
INPUT=(3600 t) x 1000 where
3
t=TIME (sec.) for 1 ft.
INPUT=(3600 x .01 x 1000 x 35.31)
T where
T = TIME (sec.) for .01 m
IMPORTANT
A boiler underfired by 5% is still
acceptable. Do not overfire the boiler.
CAUTION
Always contact your gas utility to
obtain the correct heating value
before clocking the meter.
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