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

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

8. 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 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)
where
3
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.
÷
T
natural gas
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