Viessmann Vitogas 100 GS1 Series Start-Up/Service Instructions page 11

Procedures
(continued)
I S
nitial start-up ervice
Fig. 2
Measuring manifold gas pressure using outlet pressure tap
WARNING
Ensure there are no gas leaks at inlet
pressure tap of gas valve.
IMPORTANT
A 1/8" male NPT to 1/4" barb adaptor is
required to insert in gas valve outlet
pressure tap. This adaptor is used to
connect tubing from gas valve outlet
pressure tap to manometer.
Clock natural gas meter to verify input
Ensure all other gas equipment served
1.
by the meter is turned off during
timing of gas input to Vitogas 100,
GS1 boiler.
2.Measure the time in seconds it takes
for the boiler to use 10 cu. ft. of gas.
Divide 36,000 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.
3. Check static, running and manifold gas supply pressure (continued)
For example: A Vitogas 100, GS1
(240,000 Btu/h input) requires 2
minutes 30 seconds (150 seconds) to
use 10 cu. ft. of natural gas. After
contacting the local utility, you find the
heating value is 1000 Btu per cu. ft.
Therefore,
36,000/150 x 1000 = 240,000 Btu/h
input.
Therefore, the boiler input is correct.
Burner input formulas (for low altitude
only):
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
Initial Start-up and Service Initial Start-up and Service
Manifold pressure:
9. Remove gas valve outlet pressure tap
and connect U-tube manometer or
non-electric Magnehelic
10.Open manual gas shut-off valve.
11.Activate boiler control as described in
separate Operating Instructions.
12.Measure manifold pressure. Manifold
pressure must be:
natural gas 3.5" w.c.
propane gas 10" w.c.
for normal operation at sea level. To
increase gas pressure (and flow), turn
pressure regulator adjustment screw
clockwise; to decrease gas pressure
(and flow), turn pressure regulator
adjustment screw counterclockwise.
13.Close main gas shut-off valve,
deactivate power on control via on/off
switch (boiler shuts down), disconnect
manometer, and close outlet
screw.
14.Install front boiler panel and fasten with
screw provided.
15.For natural gas, the gas meter must be
clocked to verify input. Manifold
pressure may need to be adjusted to
obtain proper input.
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.
÷
T
natural gas
®
manometer.
with
11