19
Installation info
CALCULATION OF PRESSURE LOSSES
FOR DISCHARGE AND SUCTION DUCTS
Bear in mind the following parameters when
calculating pressure losses:
- for each metre of duct with Ø 80 (both
suction and discharge) the pressure loss
is 2 Pa;
- for each 90° Ø 80 (R=D) bend with long
radius, the pressure loss is 2 Pa;
- for each 90° Ø 80 (R=½ D) bend with
short radius, the pressure loss is 6 Pa in
suction and 8 Pa in discharge;
- for the Ø 80 L = 0.5 m horizontal air inlet
terminal, the pressure loss is 3 Pa;
- for the Ø 80 L = 0.6 m horizontal
discharge end section, the pressure loss
is 5 Pa;
- 2 short radius 90° Ø 80 curves + 1
adapter Ø 80, the pressure loss is 14
Pa.
fig. 20
fig. 19
2.2.11- MEASUREMENTS OF
COMBUSTION EFFICIENCY
Ducts Ø 80 type B22 (C)
Coaxial ducts (A)
Dual ducts Ø 80 (B)
To determine combustion efficiency the fol-
lowing measurements must be made:
- the combustion air temperature measured
in hole 2 (see fig. 20).
- the flue gas temperature and CO
2
% mea-
sured in hole 1 (see fig. 20).
Make these measurements with the boiler
running in a steady state condition.
135
45
C
Sonda
analizzatore
2
1
250 min.
Sonda
analizzatore
NB: These values refer to di-
scharges through original UNI-
CAL non-flexible and smooth
ducts.
Example of check using wide radius
bends:
- 2 Ø 80 long radius 90° bends + 1 adapter
Ø 80
(14 Pa)
- (TFS 28) 17 mt duct Ø 80 x 2 =
(34 Pa)
- (TFS 24) 12 mt duct Ø 80 x 2 =
(24 Pa)
- 2 90° Ø 80 long radius bends x 4 =
8 Pa
- horizontal Ø 80 air inlet terminal =
3 Pa
- horizontal Ø 80 terminal =
5 Pa
Tot. pressure loss (TFS 28) = 60 Pa
Tot. pressure loss (TFS 24) = 50 Pa
1
2
Sonda
analizzatore
Sonda
analizzatore
Fumi
Aria
A
Example N.2 (fig. 19)
Primary air suction from perimeter wall and
flue gas discharge from the same outside pe-
rimeter wall.
Maximum allowable pressure loss:
50 Pa (IVEN 04 TFS 24)
60 Pa (IVEN 04 TFS 28)
Example N.2
Aria
Sonda
analizzatore
1
Fumi
B
2
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