Unical DUA plus 30 mtank, Installation And User Instruction Manual, Page: 15 / 28

15
Installation info
Example N.2
Primary air intake from an outer wall and
smoke evacuation through the same wall.
Maximum allowed pressure drop: 50 Pa
fig. 11
CALCULATION OF PRESSURE LOSS
FOR DISCHARGE & SUCTION DUCTS
Bear in mind the following Bear in mind the following
Bear in mind the following Bear in mind the following Bear in mind the following
parameters when calculating
parameters when calculating parameters when calculating parameters when calculating parameters when calculating
pressure losses:
pressure losses:
pressure losses: pressure losses: 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 4 Pa;
- for the Ø 80 L = 0.5 m horizontal air inlet
terminal, the pressure loss is 3 Pa;
Ø 80 L = 0.6 m horizontal discharge end
section, the pressure loss is 5 Pa;
- for the adaptor from coaxial to two separate
ducts, the pressure loss is 4
Pa.
NB:
These values refer to discharges
through original UNICAL non-
flexible and smooth ducts.
In both of the following examples
the hypotized compositions of the
intake and evacuation ducts are
possible because the total pressure
loss is lower than 50 Pa, which is
the maximum allowed pressure loss.
Example of check using wide radius
bends:
- 15 m duct Ø 80 x 2 = 30 Pa
-
2 x 90° Ø 80 long radius bends 2x4= 8 Pa
- horizontal Ø 80 air inlet terminal = 3 Pa
135
45
250 min.
fig. 12
2.2.8 - ON SITE COMBUSTION
EFFICIENCY MEASUREMENT
(Type A accessories))
Coaxial ducts
To determine combustion efficiency the
following measurements must be made:
- the combustion air temperature measured
in hole
2 (see fig. 12).
- the flue gas temperature and CO
2
%
measured in hole 1 (see fig. 12).
Make these measurements with the
boiler running in a steady state
condition.
(Type B accessories))
Separate ducts
To determine combustion efficiency the
following measurements must be made:
- the combustion air temperature measured
in hole
2 (see fig. 12).
- the flue gas temperature and CO
2
%
measured in hole 1 (see fig. 12).
Make these measurements with the
boiler running in a steady state
condition.
A
B
Analyser
probes
2
1
Analyser
probes
1
2
Smokes
Air
- horizontal Ø 80 terminal = 5 Pa
-
adaptor from coaxial to
two separate ducts
Ø 80 = 4 Pa
Total pressure loss = 50 Pa
Example N.2