16
E
.0
4.
99
•
G
. 0
8.
08
.1
9
Start-up
Gas flow in operating state (V
B
)
Conversion factor (f)
Annual average air pressure
Key:
Q
n
=
boiler rating [kW]
η
K
=
efficiency [%]
H
i,n
=
lower standard calorific value [kWh/m
3
]
f =
conversion factor
B =
barometric pressure [mbar]
p
G
=
gas pressure at gas counter [mbar]
ϑ
G
=
gas temperature at gas counter [°C]
Flow measurement
Determining flow duration at gas meter.
Calculated flow duration in seconds t
spec
for a flow volume of 200 litres (corresponding to 0.2 m
3
)
for the example given above is:
V
B
= 3,3 m
3
/h
Gas flow setting
Mean geodesic height of
supplied region ASL [m]
from
1
51
101
151
201
251
301
351
401
451
501
551
601
651
701
to
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
Annual average of
air pressure
(mbar) 1016 1013 1007 1001
995
989
983
977
971
965
959
953
947
942
936
930
Measured flow duration in seconds [s]
Measures
Greater than calculated flow duration t
spec
Increase gas flow
Less than calculated flow duration t
spec
Reduce gas flow
Equal to calculated flow duration t
spec
Gas flow achieved
V
B
V
n
f
------
3 1
m
3
h
-------
,
0 94
,
-----------------
=
3 3
m
3
h
-------
,
=
=
f
B P
G
+
1013
--------------
273
273
ϑ
G
+
--------------------
×
=
t
soll
0 2
m
3
3600
s
h
---
×
,
V
B
m
3
h
------
--------------------------------------
720
m
3
s
h
---
V
B
m
3
h
------
--------------------
720
m
3
s
h
---
3 3
m
3
h
------
,
-------------------
218
s
=
=
=
=